medical research vocabulary

• U.S. Department of Health & Human Services

• Virtual Tour
• Staff Directory
• En Español

You are here

Nih clinical research trials and you, glossary of common terms, clinical research.

Clinical research is medical research that involves people to test new treatments and therapies.

Clinical Trial

A research study in which one or more human subjects are prospectively assigned to one or more interventions (which may include placebo or other control) to evaluate the effects of those interventions on health-related biomedical or behavioral outcomes.

Healthy Volunteer

A Healthy volunteer is a person with no known significant health problems who participates in clinical research to test a new drug, device, or intervention.

Inclusion/Exclusion Criteria

Inclusion/Exclusion Criteria are factors that allow someone to participate in a clinical trial are inclusion criteria . Those that exclude or not allow participation are exclusion criteria .

Informed Consent

Informed consent explains risks and potential benefits about a clinical trial before someone decides whether to participate.

Patient Volunteer

A patient volunteer has a known health problem and participates in research to better understand, diagnose, treat, or cure that disease or condition.

Phases of Clinical Trials

Clinical trials are conducted in “phases.” The trials at each phase have a different purpose and help researchers answer different questions.

• Phase I trials — An experimental drug or treatment in a small group of people (20–80) for the first time. The purpose is to evaluate its safety and identify side effects.
• Phase II trials — The experimental drug or treatment is administered to a larger group of people (100–300) to determine its effectiveness and to further evaluate its safety.
• Phase III trials — The experimental drug or treatment is administered to large groups of people (1,000–3,000) to confirm its effectiveness, monitor side effects, compare it with standard or equivalent treatments.
• Phase IV trials — After a drug is licensed and approved by the FDA researchers track its safety, seeking more information about its risks, benefits, and optimal use.

A placebo is a pill or liquid that looks like the new treatment but does not have any treatment value from active ingredients.

A Protocol is a carefully designed plan to safeguard the participants’ health and answer specific research questions.

Principal Investigator

A Principal Investigator is a doctor who leads the clinical research team and, along with the other members of the research team, regularly monitors study participants’ health to determine the study’s safety and effectiveness.

Randomization

Randomization is the process by which two or more alternative treatments are assigned to volunteers by chance rather than by choice.

Single- or Double-Blind Studies

Single- or double-blind studies (also called single- or double-masked studies) are studies in which the participants do not know which medicine is being used, so they can describe what happens without bias. In single-blind ("single-masked") studies, you are not told what is being given, but the research team knows. In a double-blind study, neither you nor the research team are told what you are given; only the pharmacist knows. Members of the research team are not told which participants are receiving which treatment, in order to reduce bias. If medically necessary, however, it is always possible to find out which treatment you are receiving.

Types of Clinical Trials

• Diagnostic trials determine better tests or procedures for diagnosing a particular disease or condition.
• Natural history studies provide valuable information about how disease and health progress.
• Prevention trials look for better ways to prevent a disease in people who have never had the disease or to prevent the disease from returning.
• Quality of life trials (or supportive care trials) explore and measure ways to improve the comfort and quality of life of people with a chronic illness.
• Screening trials test the best way to detect certain diseases or health conditions.
• Treatment trials test new treatments, new combinations of drugs, or new approaches to surgery or radiation therapy.

This page last reviewed on April 20, 2023

Connect with Us

• More Social Media from NIH

An official website of the United States government

Here's how you know

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

NIA Glossary of Clinical Research Terms

Adverse Event (AE) – Any untoward or unfavorable medical occurrence in a clinical research study participant, including any abnormal sign (e.g. abnormal physical exam or laboratory finding), symptom, or disease, temporally associated with the participants’ involvement in the research, whether or not considered related to participation in the research.

Baseline – The initial time point in a clinical trial that provides a basis for assessing changes in subsequent assessments or observations. At this reference point, measurable values such as physical exam, laboratory tests, and outcome assessments are recorded.

Bias – A point of view or preference which prevents impartial judgment in the way in which a measurement, assessment, procedure, or analysis is carried out or reported.

Case Report Form (CRF) – A printed, optical, or electronic (eCRF) document designed to capture all protocol-required information for a study.

Coordinating Center (CC) – A group organized to coordinate the planning and operational aspects of a multi-center clinical trial. CCs may also be referred to as Data Coordinating Centers (DCCs) or Data Management Centers (DMCs).

Clinical Research or Study Coordinator (CRC) – An individual that handles the administrative and day-to-day responsibilities of a clinical trial and acts as a liaison for the clinical site. This person may collect the data or review it before it is entered into a study database.

Clinical Research – NIH defines clinical research as:

• Patient-oriented research. Research conducted with human subjects (or on material of human origin such as tissues, specimens and cognitive phenomena) for which an investigator directly interacts with human subjects. Excluded from this definition are in vitro studies that utilize human tissues that cannot be linked to a living individual. Patient-oriented research includes: (a) mechanisms of human disease, (b) therapeutic interventions, (c) clinical trials, or (d) development of new technologies.
• Epidemiologic and behavioral studies .
• Outcomes research and health services research.

Clinical Trial – NIH defines a clinical trial as a research study in which one or more human subjects are prospectively assigned to one or more interventions (which may include placebo or other control) to evaluate the effects of those interventions on health-related biomedical or behavioral outcomes. Clinical trials are used to determine whether new biomedical or behavioral interventions are safe, efficacious, and effective. Behavioral clinical trials involving an intervention to modify behavior (diet, physical activity, cognitive therapy, etc.) fit this definition of a clinical trial.

Concomitant Medication – Prescription and over-the-counter drugs and supplements a study participant has taken along with the study intervention. This information may be collected as a history item as well as during the study. Some studies may collect only those medications that may interact with the study or intervention or that may exclude an individual from participating in a study.

Conflict of Interest – A conflict of interest occurs when individuals involved with the conduct, reporting, oversight, or review of research also have financial or other interests, from which they can benefit, depending on the results of the research. Control Group – The group of individuals in a clinical trial assigned to a comparison intervention.

Controlled Clinical Trial – A clinical trial in which at least one group of participants is given a test intervention, while at least one other group concurrently receives a control intervention.

Data Management – The processes of handling the data collected during a clinical trial from development of the study forms/CRFs through the database locking process and transmission to statistician for final analysis.

Data Management Plan (DMP) – A plan that documents the processes for handling the flow of data from collection through analysis. Software and hardware systems along with quality control and validation of these systems, as relevant are described.

Data and Safety Monitoring Board (DSMB) –A group of individuals independent of the study investigators that is appointed by the NIA to monitor participant safety, data quality and to assess clinical trial progress.

Data and Safety Monitoring Plan (DSMP) – Plan included with the grant application for clinical trials which establishes the overall framework for data and safety monitoring, how adverse events will be reported to the IRB and the NIH and, when appropriate, how the NIH Guidelines and FDA regulations for INDs and IDEs will be satisfied. 

Efficacy – Indication that the clinical trial intervention produces a desired therapeutic effect on the disease or condition under investigation.

Eligibility Criteria – List of criteria guiding enrollment of participants into a study. The criteria describe both inclusionary and exclusionary factors, (e.g. inclusion criterion - participants must be between 55 and 85 years old; exclusion criterion – must not take drug X three month prior to the study). Food and Drug Administration (FDA)  – An agency within the U.S. Department of Health and Human Services (DHHS) responsible for protecting the public health by assuring the safety, efficacy, and security of human and veterinary drugs, biological products, medical devices, nation’s food supply, cosmetics, and products that emit radiation.

Good Clinical Practice – A standard for the design, conduct, performance, monitoring, auditing, recording, analyses, and reporting of clinical trials that provides assurance that the data and reported results are credible and accurate, and that the rights, integrity, and confidentiality of trial participants are protected.

Health Insurance Portability and Accountability Act (HIPAA) Privacy Rule – The first comprehensive Federal protection for the privacy of personal health information. The Privacy Rule regulates the way certain health care groups, organizations, or businesses, called covered entities under the Rule, handle the individually identifiable health information known as protected health information (PHI).

Human Subject – A patient or healthy individual who is or becomes a participant in research, either as a recipient of the intervention or as a control.

Informed Consent – A process by which a participant or legal guardian voluntarily confirms his or her willingness to participate in a particular trial, after having been informed of all aspects of the trial that are relevant to the participant’s decision to take part in the clinical trial. Informed consent is usually documented by means of a written, signed, and dated informed consent form, which has been approved by an IRB/IEC .

Informed Consent Form – A document that describes the rights of a study participant and provides details about the study, such as its purpose, duration, required procedures, and key contacts. Risks and potential benefits are explained in the informed consent document. Institutional Review Board (IRB)/Independent Ethics Committee (IEC) – An independent body constituted of medical, scientific, and nonscientific members whose responsibility it is to ensure the protection of the rights, safety, and well-being of human subjects involved in a trial by, among other things, reviewing, approving, and providing continuing review of trials, protocols and amendments, and of the methods and material to be used to obtaining and documenting informed consent of the trial participant.

Intervention – A procedure or treatment such as a drug, nutritional supplement, gene transfer, vaccine, behavior or device modification that is performed for clinical research purposes.

Investigational New Drug Application (IND) – An IND is a request for authorization from the Food and Drug Administration (FDA) to administer an investigational drug or biological product to humans. Such authorization must be secured prior to interstate shipment and administration of any new drug or biological product that is not the subject of an approved New Drug Application or Biologics/Product License Application (21 CFR 312).

Masking/Blinding – A procedure in which the investigator administering the assessments and intervention as well as the participants in a clinical trial are kept unaware of the treatment assignment(s). Single blinding usually refers to the study participant(s) being unaware, and double blinding usually refers to the study participant(s) and any of the following being unaware of the treatment assignment(s): investigator(s), monitor, and data analyst(s).

Manual of Procedures (MOP) – A set of procedures describing study conduct. A MOP is developed to facilitate consistency in protocol implementation and data collection across study participants and clinical sites.

N ew Drug Application (NDA) – An application submitted by the manufacturer of a drug to the FDA, after the clinical trial has been completed, for a license to market the drug for a specified indication.

Observational Study Monitoring Board (OSMB)  – The safety and data monitoring body for observational studies with large or vulnerable populations or risks associated with tests or standard of care.  

Office for Human Research Protection (OHRP) – A federal government agency within the Department of Health and Human Services (DHHS) charged with the protection of human subjects participating in government funded research. It issues assurances and oversees compliance of regulatory guidelines by research institutions.

Open-Label Trial – A clinical trial in which investigators and participants know which intervention is being administered.

Pharmacokinetics – The process (in a living organism) of absorption, distribution, metabolism, and excretion of a drug or vaccine.

Phase I – clinical trials to test a new biomedical intervention in a small group of people (e.g., 20-80) for the first time to evaluate safety (e.g., to determine a safe dosage range and to identify side effects). It can include healthy participants or patients.

Phase II – clinical trials to study the biomedical or behavioral intervention in a larger group of people (several hundred) to determine efficacy and to further evaluate its safety. It is conducted in participants with the condition or disease under study and will determine common short-term side effects and risks.

Phase III – studies to investigate the efficacy of the biomedical or behavioral intervention in large groups of human subjects (from several hundred to several thousand) by comparing the intervention to other standard or experimental interventions as well as to monitor adverse effects, and to collect information that will allow the intervention to be used safely.

An NIH-defined Phase III clinical trial is a broadly based prospective Phase III clinical investigation, usually involving several hundred or more human subjects, for the purpose of evaluating an experimental intervention in comparison with a standard or controlled intervention or comparing two or more existing treatments. Often the aim of such investigation is to provide evidence leading to a scientific basis for consideration of a change in health policy or standard of care. The definition includes pharmacologic, non-pharmacologic, and behavioral interventions given for disease prevention, prophylaxis, diagnosis, or therapy. Community trials and other population-based intervention trials are also included.

Phase IV – studies conducted after the intervention has been marketed. These studies are designed to monitor effectiveness of the approved intervention in the general population and to collect information about any adverse effects associated with widespread use.

Placebo – A placebo is an inactive pill, liquid, powder, or other intervention that has no treatment value. In clinical trials, experimental treatments are often compared with placebos to assess the treatment's effectiveness.

Placebo Controlled Study  – A method of investigation in which an inactive substance/treatment (the placebo) is given to one group of participants, while the test article is given to another group. The results obtained in the two groups are then compared to see if the investigational treatment is more effective in treating the condition.

Protocol – A document that describes the objective(s), design, methodology, statistical consideration, and organization of a trial.

Protocol Amendments – A written description of a change(s) to or formal clarification of a protocol.

Protocol Deviations – Failure to conduct a study as described in the protocol. The failure may be accidental or due to negligence and in either case, the protocol deviation should be documented. This also includes failure to comply with federal laws and regulations, the institution's commitments and policies, and standards of professional conduct and practice. Examples of noncompliance include:

• failure to obtain/maintain approval for research,
• failure to obtain informed consent when required,
• failure to file adverse event reports,
• performance of an unapproved study procedure,
• performance of research at an unapproved site,
• failure to file protocol modifications and
• failure to adhere to an approved protocol.

Protocol Deviations Report – Internal document created as part of the ongoing quality control process summarizing compliance with the protocol and listing protocol deviations and/or violations.

Prospectively Assigned  – A pre-defined process (e.g., randomization) specified in an approved protocol that stipulates the assignment of research subjects (individually or in clusters) to one or more arms (e.g., intervention, placebo or other control) of the clinical trial. 

Quality Assurance (QA) – Systematic approach to ensure that the data are generated, documented (recorded), and reported in compliance with the protocol and good clinical practice (GCP) standards.

Quality Control (QC) – The internal operational techniques and activities undertaken within the quality assurance system to verify that the requirements for quality of trial related activities have been fulfilled (e.g., data and form checks, monitoring by study staff, routine reports, correction actions, etc.).

Randomization – The process of assigning clinical trial participants to treatment or control groups using an element of chance to determine the assignments in order to reduce bias.

Recruitment Plan – The plan that outlines how individuals will be recruited for the study and how the study will reach the recruitment goal.

Retention Plan – The plan that details the methods in which the study will use in order to retain study participation in the clinical trial.

Safety Monitoring Plan – A plan that outlines the oversight of a clinical trial.

Safety Officer (SO)  – An independent individual, often a clinician who is appointed by the NIA and performs data and safety monitoring activities in low-risk, single site clinical studies. The SO advises the NIA regarding participant safety, scientific integrity, and ethical conduct of a study. The SO is advisory to the Institute Director. 

Screening Log – An essential document that records all individuals who entered the screening process. The screening log demonstrates the investigator’s attempt to enroll a representative sample of participants.

Screening Process – A process designed to determine individual’s eligibility for participation in a clinical research study.

Serious Adverse Event (SAE) – Any adverse event that:

• Results in death
• Is life threatening, or places the participant at immediate risk of death from the event as it occurred
• Requires or prolongs hospitalization
• Causes persistent or significant disability or incapacity
• Results in congenital anomalies or birth defects
• Is another condition which investigators judge to represent significant hazards

Source Document – Original documents, data, and records (e.g., hospital records, clinical and office charts, laboratory notes, memoranda, participant diaries, recorded data from automated instruments, x-rays, etc.) that are used in a clinical trial.

Standard Operating Procedure (SOPs) – Detailed written instructions to achieve uniformity of the performance of a specific function across studies and patients at an individual site.

Stopping Rules –Established safety criteria that would either pause or halt a study due to reasons including but not limited to futility or risk(s) to the participants.

Stratification – Separation of a study cohort into subgroups or strata according to specific characteristics such as age, gender, etc., so that factors which might affect the outcome of the study, can be taken into account.

Unanticipated Problems (UAPs) – Unanticipated problems involving risks to subjects or others, which meet all of the following criteria:

• Unexpected in terms of nature, severity, or frequency;
• Related or possibly related to participation in the research, and;
• Suggests that the research placces subjects or others at a greater risk of harm (including physical, psychological, economic, or social harm) than was previously known or recognized.

Unmasking/Unblinding – A procedure in which one or more parties to the trial are made aware of the treatment assignment(s).

Unanticipated Adverse Device Effects (UADEs) – Any serious adverse effect on health or safety or any life-threatening problem or death caused by, or associated with, a device, if that effect, problem, or death was not previously identified in a nature, severity, or degree of incidence in the investigational plan or application (including a supplementary plan or application) or any other unanticipated serious problem associated with a device that relates to the rights, safety, or welfare of subjects.

Glossary Sources:

Clinical Trials.gov NINDS Glossary of Clinical Research Terms CenterWatch, Inc. Patient Resources: Glossary. OHRP website NIH Definitions Friedman LM, Furberg CD, DeMets DL. Fundamentals of Clinical Trials (3 ed.). Missouri: Mosby-Year Book Inc., 1996. Meinert CL. Clinical Trials: Design, Conduct, and Analysis . New York: Oxford University Press, Inc., 1986.

Return to the NIA Clinical Research Investigator's Toolbox .

Last updated: February 22, 2023

Related Content

Approved Concepts

Grants & Funding

Research Resources

nia.nih.gov

An official website of the National Institutes of Health

Welcome to the SOM Clinical Research Glossary

Quickly look up the meaning of words, acronyms, or abbreviations commonly used in clinical research:

• Narrow your search by typing the word you are looking for in the search box. Clear the search box to start a new search.
• Use the alphabet bar for quick filtering of words by first letter or select a word category to explore words that are related. Remove the letter or word filters by clicking the respective ALL button.

Return to the glossary index page after each word search using the « Back to Glossary Index link.

• Adverse Drug Reaction (ADR)
• Adverse Event (AE)
• Adverse Reaction (AR)
• Age of majority
• AIR (Activities Interests and Relationships)
• ALCOA (Attributable, Legible, Contemporaneous, Original, Accurate)
• ALCOA Plus, ALCOA+
• Ancillary review
• Applicable Clinical Trial (ACT)
• Applicable regulatory requirements
• Approved drug
• Aspirational benefit
• Association for Clinical and Translational Science (ACTS)
• Association for the Accreditation of Human Research Protection Programs (AAHRPP)
• Association of Clinical Research Professionals (ACRP)
• Audit report
• Audit trail
• Baseline assessment
• Billing Coverage Analysis (BCA)
• Biological Product
• Biological specimen
• Biologics License Application (BLA)
• Biomedical Research Imaging Center (BRIC)
• Biospecimen
• Biospecimen Processing Facility (BSP)
• Breach of confidentiality
• Budget justification
• Budget period
• Budget revision
• Business Associate
• Business Associate Agreement (BAA)
• Carolina Data Warehouse for Health (CDW-H)
• Case Report Form (CRF)
• Ceded review
• Centers for Disease Control and Prevention (CDC)
• Centers for Medicare & Medicaid Services (CMS)
• Centralized monitoring
• Certificate of Confidentiality (CoC)
• Certified copy
• Clinical and Translational Research Center (CTRC)
• Clinical and Translational Science Awards (CTSA) Program
• Clinical development
• Clinical investigation
• Clinical monitor
• Clinical research
• Clinical Research Accountability Unit (CRAU)
• Clinical Research Associate (CRA)
• Clinical Research Coordinator (CRC)
• Clinical Research Management System (CRMS)
• Clinical Research Support Office (CRSO)
• Clinical significance
• Clinical study
• Clinical trial
• Clinical Trial Agreement (CTA)
• ClinicalTrials.gov
• Clinical Trials Quality Assurance (CTQA) Program
• Code of Federal Regulations (CFR)
• Co-investigator
• Collaborative Institutional Training Initiative (CITI)
• Collateral benefit
• Commercial Institutional Review Board (IRB)
• Common data model
• Common Rule
• Common Terminology Criteria for Adverse Events (CTCAE)
• Compensation
• Competitive Renewal
• Computable Phenotype
• Concomitant medication
• Confidential Disclosure Agreement (CDA)
• Confidentiality
• Conflict of Interest (COI)
• Conflict of Interest Office
• Consent capacity
• Continuing noncompliance
• Continuing review
• Contract Research Organization (CRO)
• Control group
• Coordinating Center (CC)
• Corrective and Preventive Action (CAPA) Plan
• Data acquisition
• Data and Safety Monitoring Board (DSMB)
• Data and Safety Monitoring Committee (DSMC)
• Data and Safety Monitoring Plan (DSMP)
• Database Management System (DBMS)
• Data encryption
• Data Integrity
• Data management
• Data Management and Sharing Plan (DMS Plan)
• Data Management Plan (DMP)
• Data Management System (DMS)
• Data Monitoring Committee (DMC)
• Data Use Agreement (DUA)
• Delegation of Authority (DOA) Log
• Demographic data
• Department of Health and Human Services (DHHS)
• Direct benefit
• Direct cost
• Disapproval
• Discontinue
• Disease registry
• Dosage regimen
• Dose Limiting Toxicity (DLT)
• Double blinding
• Drug toxicity
• ECRT (Effort Certification and Reporting Technology)
• Electronic Case Report Form (eCRF)
• Electronic Data Capture (EDC)
• Electronic Health Record (EHR)
• Electronic Informed Consent (eIC)
• Electronic Medical Record (EMR)
• Elements of informed consent
• Eligibility criteria
• Embryonic Stem Cell Research Oversight (ESCRO) Committee
• Encounter Level Data
• Environment, Health and Safety (EHS)
• Essential document
• Exclusion criteria
• Exculpatory language
• Exempt review
• Expanded access
• Expedited review
• Experimental drug
• Experimental group
• Export Compliance Office
• Export control
• Fabrication
• Falsification
• Family Educational Rights and Privacy Act (FERPA)
• FDA Form 482
• FDA Form 483
• FDA Form 1571
• FDA Form 1572
• Feasibility assessment
• Federalwide Assurance (FWA)
• Food and Drug Administration (FDA)
• Food, Drug and Cosmetics Act
• Free text data
• Full board review
• Generalizability, Generalization
• Good Clinical Practice (GCP)
• Grant application
• Grant Number
• Greater than minimal risk
• Health literacy
• Healthy volunteer
• HIPAA authorization
• HIPAA covered entity
• HIPAA (Health Insurance Portability and Accountability Act)
• HIPAA Privacy Rule
• Humanitarian Device Exemption (HDE)
• Humanitarian Use Device (HUD)
• Human Research Protection Program (HRPP)
• Human subject
• Human Subjects Research (HSR)
• Identifiable biospecimen
• Identifiable private information
• Impartial witness
• Inclusion criteria
• Inclusion/Exclusion (I/E) criteria
• Independent Ethics Committee (IEC)
• Independent IRB
• Indirect benefit
• Indirect Facility & Administrative (F&A) costs
• Individual Conflict of Interest (COI)
• Industry Contracting (IC)
• Industry sponsored study
• Informed Consent Form (ICF)
• Informed Consent (IC)
• Institution
• Institutional Biosafety Committee (IBC)
• Institutional Conflict of Interest (COI)
• Institutional Integrity and Risk Management (IIRM)
• Institutional Official (IO)
• Institutional Privacy Office (IPO)
• Institutional Privacy Officer
• Institutional Review Board Information System (IRBIS)
• Institutional Review Board (IRB)
• Interaction
• International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9CM)
• International Council for Harmonisation (ICH)
• Intervention
• Interventional study
• Investigation
• Investigational device
• Investigational Device Exemption (IDE)
• Investigational drug
• Investigational Drug Service (IDS)
• Investigational New Drug (IND)
• Investigational New Drug (IND) safety report
• Investigational plan
• Investigational product (IP)
• Investigator
• Investigator agreement
• Investigator-initiated study
• Investigator's Brochure (IB)
• IRB application
• IRB approval
• IRB Authorization Agreement (IAA)
• IRB expiration
• IRB of record
• Just-in-Time (JIT)
• Key information
• Legally Authorized Representative (LAR)
• Legally effective informed consent
• Letter of intent
• Life-threatening adverse event
• Limited dataset
• Lineberger Comprehensive Cancer Center (LCCC)
• Local considerations
• Longitudinal study
• Long Term Follow-Up (LTFU)
• Lost to Follow Up (LTFU)
• Manual of procedures (MOP)
• Material transfer agreement (MTA)
• Medical device
• Medical monitor
• Medical record
• Medical Record Number (MRN)
• Memorandum of understanding (MOU)
• Minimal risk
• Monitoring plan
• Monitoring report
• Multicenter study
• Multisite study
• National Institutes of Health (NIH)
• New Drug Application (NDA)
• NIH National Library of Medicine (NLM)
• NIH Public Access Policy
• No Cost Extension (NCE)
• Nonclinical study
• Noncompliance
• Nondisclosure agreement (NDA)
• Nonsignificant Risk (NSR) medical device
• Nonsignificant Risk (NSR) medical device study
• North Carolina Translational and Clinical Sciences (NC TraCS) Institute
• Not Human Subjects Research (NHSR)
• Notice of Award (NOA)
• Notice of privacy practices
• Not reasonably available (as it applies to locating a parent)
• Observational study
• Observational Study Monitoring Board (OSMB)
• Office for Human Research Protections (OHRP)
• Office for Innovation, Entrepreneurship and Economic Development (IEED)
• Office of Clinical Trials (OCT)
• Office of Human Research Ethics (OHRE)
• Office of Research Communications (ORC)
• Office of Research Development (ORD)
• Office of Research Information Systems (ORIS)
• Office of Research (OoR)
• Office of Research Support and Compliance (ORSC)
• Office of Sponsored Research (OSR)
• Office of Technology Commercialization (OTC)
• Office of the Vice Chancellor for Research (OVCR)
• Office of University Counsel (OUC)
• Off-label use
• On-site monitoring
• Open-label trial
• Organizational Conflict of Interest (COI)
• Package insert
• Parental permission
• Participant
• Participant engagement
• Participant partners
• Participating site
• Patient Centered Outcomes Research Network (PCORnet)
• Patient level data
• Patient registry
• Personnel Profile and Training System (PaTS)
• Pharmacogenomics
• Pharmacokinetics (PK)
• Pilot study
• Placebo effect
• Plain language
• Possibly related to the research
• Pragmatic trial
• Preclinical research
• Principal Investigator (PI)
• Privacy board
• Privacy Rule
• Private information
• Program announcement
• Program officer
• Promptly Reportable Information (PRI)
• Prospective study
• Protected Health Information (PHI)
• Protocol amendment
• Protocol deviation
• Protocol Review Committee (PRC)
• PubMed Central (PMC)
• Quality Assurance (QA)
• Quality Control (QC)
• Quality Improvement (QI)
• Questionnaire
• Radiation Safety Committee (RSC)
• Radiation Safety Subcommittee (RSS)
• Radioactive Drug Research Committee (RDRC)
• RAMSeS (Research Administration Management System & electronic Submission)
• Randomization
• Reasonable possibility
• Recruitment
• Recruitment period
• Recruitment plan
• Recruitment status
• REDCap (Research Electronic Data Capture)
• Registry study
• Regulatory binder
• Reliance agreement
• Relying Institution
• Research administrator
• Research Compliance Program (RCP)
• Research Coordination & Management Unit (RCMU)
• Research misconduct
• Research personnel
• Research plan
• Research registry
• Research study
• Research team
• Research team members
• Responsible conduct of research
• Retention plan
• Retrospective study
• Reviewing IRB
• Reviewing IRB Institution
• Risk-based monitoring
• Root Cause Analysis (RCA)
• Safety and Security Committee
• Schedule of activities (SOA)
• Schedule of Assessments
• School of Medicine (SOM)
• Scientific Review Committee (SRC)
• Screen failure
• Screening log
• Sensitive Information (SI)
• Serious Adverse Event (SAE)
• Serious and Unexpected Suspected Adverse Reaction (SUSAR)
• Serious noncompliance
• Short form consent
• Side effects
• Significant Risk (SR) medical device
• Significant Risk (SR) medical device study
• Single blinding
• Single IRB (sIRB)
• Site Initiation Visit (SIV)
• Site investigator
• Site Master File (SMF)
• Society of Clinical Research Associates (SoCRA)
• SOM Conflict of Interest Committee (COIC)
• Source data
• Source documents
• Sponsored Program Office (SPO)
• Sponsored Research Agreement (SRA)
• Sponsor-investigator
• Standard of Care (SOC)
• Standard Operating Procedure (SOP)
• Stopping rules
• Stratification
• Structured data
• Study Coordinator (SC)
• Study design
• Study documentation
• Study monitor
• Study population
• Sub-investigator
• Subject binder
• Subject chart
• Subject identification number/code
• Suspected Adverse Reaction
• Target enrollment
• Termination
• Test article
• Therapeutic misconception
• Tolerability
• Trial Master File (TMF)
• Unanticipated Adverse Device Effect (UADE)
• Unanticipated Problem Involving Risk to Subjects or Others (UPIRSO)
• UNC Health Network Entities
• UNC Health Privacy Office
• Underserved population
• Unexpected adverse event
• University of North Carolina at Chapel Hill
• Vulnerable populations
• Washout Period
• Work Instruction (WI)

We appreciate your input!

Working together, we can reimagine medicine to improve and extend people’s lives.

Glossary of Clinical Trial Terms

There are a lot of words and terms about clinical research that may be new to you. This section provides definitions for words and terms you may want to know.

A  -  B  -  C  -  D  -  E  -  F  - G -  H  -  I  - J - K - L -  M  - N -  O  -  P  - Q -  R  -  S  - T - U -  V  -  W  - X - U - Z

Adverse Event

A negative change or medical occurrence that happens during a clinical trial or within a certain time period after the trial has ended. An adverse event may or may not be caused by the treatment being studied.

Arm assignment

The assignment of a group or subgroup of participants in a clinical trial to receive interventions, or no interventions, as specified in the study protocol.

A procedure (e.g. a blood test, scan, etc.) used to generate data required by the trial.

Background therapy

Background therapy is the current medication that is routinely taken as a standard of care for a particular condition/disease.

A type of clinical trial design in which one or more parties involved with the trial, such as the research team or participant, do not know which treatments have been assigned to which participants. See Double-blind and Single-blind below.

Control 

The control or “standard” treatment is compared against the investigational treatment. It is there to show that an approved treatment in the trial works, and the investigational treatment is compared against it.

Clinical study

A research study conducted in human volunteers to answer specific health questions. Interventional studies determine whether experimental treatments or new ways of using known therapies are safe and effective under controlled environments. 

Cross-over trial

A clinical trial where groups of volunteers are administered two or more interventions in a specific order. For example, a “two-by-two” cross-over trial design is where one group receives drug A at the beginning of the trial and then receives drug B for the rest of the trial. In the second group, participants receive drug B first and then drug A. Thus, the term “cross-over” is used to describe the order in which they are assigned; for example drug A and then drug B, or drug B and then drug A. All participants receive both drugs during the study.

Dosing discontinuation

Point/time when a patient volunteer permanently stops taking study drug for any reason. This may be at the end of the study or before the end if the patient wants to stop taking the medicine for some reason.

Double-blind

In a double-blind trial, only the study pharmacist knows what study medication a participant is receiving; the participants, doctors, nurses, and other clinical trial staff are not informed.

Early patient withdrawal (premature withdrawal) 

Point/time when a patient exits from a trial prior to the planned completion of all investigational/trial drug administration and all assessments (including follow-up).

Eligibility Criteria

The requirements that people who want to participate in a clinical study must meet. Eligibility Criteria include both inclusion criteria and exclusion criteria and are defined in the protocol.

European Medicines Agency (EMA)

European Medicines Agency. An agency of the European Union that oversees the use of medicinal products. 

The point, or time, of a volunteer’s entry into the trial, after informed consent has been obtained. The same term may also be used to define the number of participants in a clinical trial. 

Epoch 

The planned stage of the volunteers’ participation in the trial. Typical epochs are: determination of subject eligibility, wash-out of previous treatments (i.e., a period of time when previous treatments are stopped), exposure of subject to treatment, or the follow-up on subjects after treatment has ended.

Food and Drug Administration (FDA)

Food and Drug Administration. A government agency within the U.S. Department of Health and Human Services that oversees the Nation's public health by making sure that human and veterinary drugs, vaccines, biological products, medical devices, cosmetics, dietary supplements, the food supply, and any products that give off radiation are safe, effective, and secure.

Health Authority

A national or international health agency that has authority over and regulates a clinical study.

A disease, symptom, or particular set of circumstances that make a particular test, medication, procedure, or surgery advisable. For a treatment, an indication refers to the use of that treatment in treating a particular disease.

Informed consent

Informed consent is used by researchers to explain the clinical trial to potential volunteers. Its purpose is to protect the participant. It is used when somebody who is interested in participating first asks about the study and it continues throughout the study, until the study ends. The research team will review the details of the trial with the potential participant and will answer any questions. This information is also written in a document, known as the informed consent form, which is designed to be clear and easy to understand. If a person decides to enrol in a clinical trial, they will sign the informed consent form to acknowledge that they understand the details of the trial and consent to participating. The informed consent form is not a contract and the participant can withdraw from the trial at any time, and for any reason. 

Institutional Review Board (IRB)

An IRB (also known as an independent ethics committee (IEC), ethical review board (ERB) or research ethics board (REB)) is a group of doctors, scientists, advocates, researchers, and members of the community that has been formally designated to review and monitor all research involving humans. IRBs are in place to provide ethical oversight and to minimize risk to participants.

Interventional study 

Also known as a clinical trial, a type of clinical study in which participants receive one or more interventions, according to the protocol and group that they are assigned to, so that researchers can evaluate the effects of the intervention on a health condition.

Investigational drug 

The drug being evaluated in the trial; this definition is synonymous with “investigational new drug” or “investigational medicinal product.”

Medication number 

A unique number on the label of each investigational drug package that is used in a trial to dispense and track medication. The number is used to make sure the drug is supplied in the right quantities to different research centers.

Observational study

An observational study investigates health outcomes amongst groups of people in the course of their everyday life at home, work, or the doctor’s office, where assignment of treatments or other procedures is as part of their regular medical care (not assigned by an investigator).

Outcome measure

In clinical trials, a set measurement that is described in the protocol and is used to evaluate the effect of an intervention on participants.

A subdivision of a single protocol into major building blocks. These parts often are independent of each other and have different objectives or different groups of volunteers. For example, a single-dose design and a multiple-dose design may be combined into one protocol (a protocol with two parts) or the same study design could be used with different groups of patients with different severity of a disease.

Categories, defined by the Food and Drug Administration (FDA), for describing the clinical trial of a drug based on the study's characteristics, such as the objective and number of participants. There are four phases:

• Phase I trials test an experimental drug, vaccine or device in a small group of people to evaluate safety, identify side effects and determine safe dosages. 
• Phase II trials involve larger groups of people than Phase I and they are designed to assess whether an experimental treatment is safe and whether it works. This phase can last several years. 
• Phase III trials are usually large studies comparing the experimental drug or vaccine to a placebo or standard treatment, to evaluate whether the drug works and collect information to allow it to be used safely. 
• Phase IV trials are performed once a drug has reached the market, to provide additional information about the best use of the drug.

Placebos are inactive substances. In a clinical trial a placebo, made to look like the investigational treatment, is sometimes used to compare against the actual investigational treatment to evaluate effectiveness. 

Principal Investigator

The person who is responsible for the scientific and technical direction of the clinical trial at a specific clinical site. In most cases the principal investigator will be a leading physician in the disease area being studied. 

A written study plan on which the clinical trial is based. A protocol describes what types of people may or may not participate in the trial; the schedule of tests, procedures, medications, and dosages to be administered; the outcome measures that will be evaluated; and the length of the study.

Randomized allocation

A strategy in which participants are randomly assigned to study arms of a clinical trial by computer.

Randomization number 

A unique number assigned to each randomized patient that is used to identify individuals but maintain anonymity, corresponding to a specific study arm assignment.

Run-in period 

The elapsed time before a trial starts when no investigational drug is given to trial participants. During this time patients may still receive standard treatments for their disease if these treatments are allowed within the trial period.

Serious adverse event

An adverse event that is life-threatening, requires hospitalization or extended hospital stay, results in ongoing or significant incapacity, causes congenital anomalies or birth defects, or results in death.

The Sponsor is the organization or person who oversees multiple sites conducting the clinical trial. 

Study completed date

The date on which the last trial participant made the final visit to the study location (that is, "last subject, last visit") and the last samples were collected or last tests performed. 

An individual (either a healthy volunteer or a patient volunteer) whose reactions or responses to certain interventions are evaluated during a clinical trial. May also be referred to as a trial participant.

Subject number

A unique number assigned to each participant who enrols into a clinical trial.

Variable 

Information collected during a clinical trial either from direct or indirect data. For example, one variable might be “weight,” which would then be checked at specified time points throughout the trial.

Wash-out period

The period of time allowed for all of the administered drug to be eliminated from the body.

AddToAny buttons

Printable links block (content).

• Health Literacy Home

Clinical Research Glossary

• Best Practices

Using plain language definitions can make research materials easier to read and understand.

In Spring 2020, the MRCT Center launched a small pilot project with patients and participants and other stakeholders across the research industry, to develop plain language definitions of clinical research words.

The resulting Clinical Research Glossary is now available for use!

You can find other potentially helpful glossaries here .

Don’t forget about your verbs!

Phrasal verbs like “turn in your survey” can be confusing.  What it means to “turn in” is often not clear and may be better stated as “submit” or “return” .  Guidance and appropriate substitutions can be found here .

Clinical Trials

INTERNATIONAL VERSIONS OF THE SITE

Merck & Co, Inc, Rahway, NJ, USA, known as MSD outside of the United States and Canada, provides international versions of this site for both healthcare professionals and the general public.

Select a language below to be redirected to the MSD version of the site in your chosen language.

LATIN AMERICA

CENTRAL AMERICA

Asia Pacific

Glossary of clinical trial terms

The glossary below will help you understand clinical research terms often used by researchers and other scientists.

Active, not recruiting

The clinical trial is happening, but researchers are not looking for more participants at this time.

Adverse event

A medical problem that happens or worsens during a clinical trial or within a certain time period after the trial is over. An adverse event may or may not be caused by the investigational treatment a person took.

Clinical trial (or research study)

A clinical trial is a research study designed to learn how our bodies respond to investigational medicines or other investigational treatments. During the clinical trial, participants are assigned to get a treatment or sometimes, no treatment. The purpose of a trial is usually to find ways to prevent, diagnose, or treat a disease or other health condition.

Clinical trial phases

Any treatment (vaccine, medicine, medical device, or procedure) must go through 3 phases of clinical trials. Each phase tests the treatment’s safety, how well it works, amount (dose), and side effects.

A disease, disorder, syndrome, illness, or injury that researchers are studying.

Controlled trial

A type of clinical trial that compares one treatment to another treatment. Often, a new investigational treatment is compared to a standard or usual treatment (called the control). The control may be a group of participants in the same trial or a group of participants from an earlier trial or study.

Eligibility criteria

A clinical trial’s requirements for people who want to join. These include inclusion criteria (factors that allow a person to join a trial) and exclusion criteria (factors that prevent a person from joining a trial). For example, a trial might only accept participants who are above or below certain ages.

The number of participants in a clinical trial. The “estimated enrollment” is the number of participants that the researchers need for the trial.

Exclusion criteria

The factors (or reasons) that prevent a person from joining a clinical trial.

Expanded access

A process regulated by the federal agencies that allows pharmaceutical companies to provide a new investigational treatment (before it’s approved) to patients with serious diseases or conditions who cannot take part in a clinical trial.

Inclusion criteria

The factors (or reasons) that allow a person to join a clinical trial.

Informed consent

Informed consent is the process in which researchers talk with people who are thinking about enrolling, or have enrolled, in a clinical trial. They will have you read an informed consent form (ICF) that describes the possible benefits and risks. It tells you that taking part in the trial is voluntary, and that you may leave the trial at any time.

The goal of the informed consent process is to protect the participants who enroll in clinical trials. The informed consent process starts when a possible participant first asks for information about a trial and continues until the trial ends.

Informed consent form (ICF)

The document used in the informed consent process.

Investigational medication

A drug or biological product that is used in a clinical trial but has not been approved by health authorities (the drug is either not available for a doctor to prescribe or is available but not approved by the health authority for the use being studied).

Institutional Review Board (IRB)

A committee of doctors, data experts, community advocates, and others who help ensure that a trial is done in an ethical manner and the rights of participants are protected. They review, approve, and check on the trial’s plan (protocol) that explains what researchers will do during the trial. For example, they will review the informed consent form. Also called an ethics committee.

Open studies

Studies that are enrolling participants now or in the future, or involve drugs that are available for expanded access (may be used by certain patients before federal agency approval).

A look-alike substance that does not contain an active drug or treatment. A placebo is made to look, taste, and be given like the actual drug being studied.

The written description of a clinical trial. It includes the trial’s goals, design, and methods. It may also include data and science-related background information.

The organization or person who starts the trial, pays for it, and has authority and control over it.

A treatment that helps provide protection to certain infections, usually given as a shot.

Still have questions?

Our FAQ section has answers to commonly asked questions and a glossary of words to know.

Frequently asked questions

• UNC Chapel Hill

Clinical Research Glossary

Expand your clinical research word power with the som clinical research glossary.

Clinical research has a highly specialized vocabulary with a vast number of acronyms and abbreviations that help facilitate scientific communication. Whether you are new to clinical research or an experienced member of the research team, understanding and remembering the nuances of clinical research vocabulary can be challenging.

To ensure a consistent and clear clinical research communication, the CRSO has created the SOM Clinical Research Glossary , a comprehensive clinical research glossary in clear and plain language that aligns with industry and regulatory standards. As the glossary is intended to be broadly applicable to various types of research and audiences, its definitions provide nuances of usage. If there are variations in how key agencies are defining a term, each definition is provided.

We need your feedback

The SOM Clinical Research Glossary is intended to be a living resource that will be periodically updated with new terms and clarifications. Please let us know, if there is a word, acronym, or abbreviation you see regularly in clinical research that is not included in the glossary or if you want to propose an alternative definition.

Research Terminology

Refer to this page for definitions and explanations of common terms used in research. This list is not exhaustive and is intended as a quick reference. Main menu | Comments/Suggestions

• Education Home
• Medical Education Technology Support
• Graduate Medical Education
• Medical Scientist Training Program
• Public Health Sciences Program
• Continuing Medical Education
• Clinical Performance Education Center
• Center for Excellence in Education
• Research Home
• Biochemistry & Molecular Genetics
• Biomedical Engineering
• Cell Biology
• Genome Sciences
• Microbiology, Immunology, & Cancer Biology (MIC)
• Molecular Physiology & Biological Physics
• Neuroscience
• Pharmacology
• Public Health Sciences
• Office for Research
• Clinical Research
• Clinical Trials Office
• Funding Opportunities
• Grants & Contracts
• Research Faculty Directory
• Cancer Center
• Cardiovascular Research Center
• Carter Immunology Center
• Center for Behavioral Health & Technology
• Center for Brain Immunology & Glia
• Center for Diabetes Technology
• Center for Immunity, Inflammation & Regenerative Medicine
• Center for Membrane & Cell Physiology
• Center for Research in Reproduction
• Myles H. Thaler Center for AIDS & Human Retrovirus Research
• Child Health Research Center (Pediatrics)
• Division of Perceptual Studies
• Research News: The Making of Medicine
• Core Facilities
• Virginia Research Resources Consortium
• Center for Advanced Vision Science
• Charles O. Strickler Transplant Center
• Keck Center for Cellular Imaging
• Institute of Law, Psychiatry & Public Policy
• Translational Health Research Institute of Virginia
• Clinical Home
• Anesthesiology
• Dermatology
• Emergency Medicine
• Family Medicine
• Neurosurgery
• Obstetrics & Gynecology
• Ophthalmology
• Orthopaedic Surgery
• Otolaryngology
• Physical Medicine & Rehabilitation
• Plastic Surgery, Maxillofacial, & Oral Health
• Psychiatry & Neurobehavioral Sciences
• Radiation Oncology
• Radiology & Medical Imaging
• UVA Health: Patient Care
• Diversity Home
• Diversity Overview
• Student Resources
• GME Trainee Resources
• Faculty Resources
• Community Resources
• Glossary of Research Terms

General Research Glossary

A-110 .  “Uniform Administrative Requirements for Grants and Agreements with Institutions of Higher Education, Hospitals, and Other Non-Profit Organizations,” an OMB circular covering the award of grants and contracts, post-award requirements, and property standards.

A-133 .  “Audits of States, Local Governments, and Non-Profit Organizations,” an OMB circular setting standards for obtaining consistency and uniformity among federal agencies for the audit of recipients of federal awards.

A-21 .  “Cost Principles for Educational Institutions,” an OMB circular describing financial management procedures relevant to federal agreements with academic institutions and represent the “Cost Accounting Standards” for federal awards.

AAALAC .  American Association for the Accreditation of Lab Animal Care :  an organization that accredits research animal facilities.

Advance spending .  Authorization to expend funds on a project prior to receipt of the sponsor’s notice of award, e.g., to hire staff and purchase materials required to perform the scope of work.

Agency .  Synonym for “sponsor.”

Allowable costs .  Costs that may be charged to a grant, such as salaries and equipment, that meet the requirements of being reasonable, allocable to the project, and treated consistently at the institution, and not excluded by Circular A-21.

Audit .  A formal examination of an organization’s or individual’s accounts, financial situation, or compliance with applicable terms, laws, and regulations.

Authorized signature .  Signature of the person authorized to commit funds and facilities on grants and contracts.

AUTM .  Association of University Technology Managers .  Its mission is “to promote, support and improve academic technology transfer worldwide and demonstrate its benefits globally through education, advocacy, networking and communication.”

Award .  Funds provided by a sponsor to support a particular project.

Bequest .  An award given with few or no conditions specified, for instance to establish an endowment or to provide direct support for existing programs.

Broad Agency Announcement (BAA) .  An announcement describing a federal agency’s general research interest, soliciting proposals, and specifying the criteria for selecting proposals.

Budget .  The detailed estimate of the expenditures to be made under a project’s scope of work.

Budget category .  A section of the budget that includes a defined type of expenditure (e.g., salaries, fringe benefits, travel, patient costs).

Budget justification .  A description of the individual cost elements that together comprise the budget and the estimation methods used in costing the project.

Budget period .  The interval of time into which the project period is divided for budgetary and funding purposes:  generally one year.

CAS .  See Cost Accounting Standards

CDC .  Centers for Disease Control and Prevention (DHHS)

CFDA .  Catalog of Federal Domestic Assistance , a listing of all programs available to state and local governments, organizations, individuals, etc.

CFR .  Code of Federal Regulations:  general and permanent rules established by the Executive branch of the Federal Government.

Change order .  A written order signed by the contracting officer, modifying contract clauses or scope of work without the consent of the contractor.

Classified research .   Research sponsored by the federal government involving restrictions on the distribution or publication of the research findings or results following completion.

Close-out .  Completion of internal procedures and sponsor requirements to terminate or complete a research project.

Cognizant audit agency .  The federal office that is designated to perform audits for sponsored projects at a university (at UVA, the Department of Health and Human Services [DHHS]).

COGR .   Council on Governmental Relations , an association of colleges and universities that advise the government on the impact of its regulations on their business practices.

Competing proposal .  A proposal (1) submitted for the first time, (2) that was unfunded but is being re-submitted, or (3) for an ongoing project after the term of the original award expired.

Compliances and certifications .  Federal and state rules and requirements concerning the responsible handling of research involving human subjects, vertebrate animal care, and hazardous substances, as well as other legal issues (such as conflict of interest, drug-free workplace, etc.). Administrative officers of an institution must regularly certify, by their signature, compliance with these rules and regulations; individual investigators must comply with institutional requirements and must sign to that effect on the proposal cover sheet.

Confidentiality agreement .  A legal agreement preventing one or both party from disclosing confidential information belonging to the other party.  Also called a nondisclosure agreement.

Conflict of commitment .  Any situation in which non-university activities are sufficiently demanding of time and attention that they interfere with assigned duties or with responsibilities to students or the university.

Conflict of interest .  Situations in which employees use their positions for purposes that are, or give the appearance of being, motivated by a desire for private gain for themselves or others, such as those with whom they have family, business or other ties.

Consideration .  Anything of value that changes hands between the parties of contract.

Consortium agreement .  A document formalizing the terms and conditions under which a group of collaborative investigators (i.e., a consortium) at different institutions collaborate on a project.

Consultant .  An individual whose expertise is required by the PI to perform the research project. Consultant may be a paid or unpaid.

Continuation project (non-competing) .  A subsequent award on a project after the previous budget period has expired, on multi-year projects.  These do not compete with other proposals:  rather, satisfactory progress is assessed in determining whether to provide the next period’s funding.

Contract .  Agreement to provide services that primarily benefit the sponsor. For an award to be considered a contract, it normally must contain all of the following: detailed financial and legal requirements; specific statement of work to be performed; deliverables and/or reports required by the sponsor; accounting procedures to be followed; legally binding contract clauses.

Contract/grant officer .  A sponsor’s designee who is responsible for the business management aspects of an award.  In general, this individual works with the project (scientific) officer.

Cooperative Agreement .  An award involving greater agency involvement than a grant, during proposal preparation or in carrying out the scope of work.

Co-Principal Investigator (Co-PI) .  An investigator sharing responsibility for the direction of a research program. PHS/NIH does not recognize the concept of co-principal investigator, but does recognize multiple-PI projects.

Copyright .  A government grant of exclusivity in reproduction and sale of creative (e.g., literary, artistic, computer programs) inventions.

Cost Accounting Standards (CAS) .  Federally mandated accounting standards intended to ensure uniformity in budgeting and spending funds.

Cost-reimbursement contract/grant.   A contract or grant for which the sponsor reimburses the actual allowable costs incurred during the conduct of the work.

Cost-sharing.   University and nonfederal sponsor resources provided in support of sponsored programs; includes contributed effort and matching funds.  Cost-sharing contributions must meet the following criteria:  verifiability in University records; contributions are allowable, allocable, reasonable, and necessary to accomplish the scope of work; shared costs are not also used for other projects; and shared costs are identifiable in the proposal budget or justification.

Cover sheet .  The first page of a proposal, often in a format supplied by an agency, showing summary data on the proposal and PI, plus all required compliance check-offs

CRADA or CRDA.   Cooperative Research and Development Agreement.  A document allowing government investigators to collaborate with non-government scientists on common research projects.

CSR.   Center for Scientific Review (National Institutes of Health).  

DARPA.  Defense Advanced Research Projects Agency , the central R&D arm of the Department of Defense.

Data.  Recorded information, regardless of form or characteristic, describing the design or resulting from a scientific project.

Defense Acquisition Regulations (DAR) .  The regulations governing research projects sponsored by the Department of Defense.

Deficit.   Expenditures exceeding available funds.

Deliverable .  Items to be delivered to the sponsor, generally as required by contracts.  These might include technical reports, reagents, computer programs, etc.

DFARS.   Defense Federal Acquisition Regulation Supplement

DHHS.   Department of Health and Human Services

Direct costs.   Costs that are identified specifically with a sponsored project, such as salaries/fringe benefits, supplies, equipment, etc.

DOD.   Department of Defense (includes Air Force, Army, ARPA, and Navy)

Donation.   Transfer of equipment, money, goods, services, and property, much like a gift except often with more specific intent than the latter.

DRG .  Division of Research Grants (National Institutes of Health)

EDISON .   Interagency Extramural Invention Information Management System (for reporting of inventions created under federal funding)

Effort .  The amount of time (usually a percent of total professional effort) that individual expends on a project.

Effort report .   Periodic report of the time (as a percent of total) expended by an employee on sponsored projects and other professional activities.  The employee must sign the effort report, as required by law.

Effort, contributed .  Effort expended on a sponsored project that the sponsor does not compensate for; a form of cost sharing.

Encumbrance.   Funds set aside for a projected expense prior to their actual expenditure.

Endowment.   An income-generating fund usually provided as a gift in order to generate long-term support for faculty positions or research activities.

Equipment .  Property having a useful life of more than one year and an acquisition cost of more than $5,000 per unit on federal grants (exclusive of taxes and shipping).

Equipment, general purpose .  Equipment that can be utilized for activities other than the specific scope of work supported by a grant or contract (e.g., office equipment and furniture, computers, and photocopiers).

Equipment, government-furnished ,  Equipment provided to the university by the federal government or a government contractor; title may or may not remain with the government.

Equipment, special purpose .  Equipment that can be utilized only for research, medical, scientific, or technical activities.

Expanded authorities .  A policy of some federal granting agencies, which delegate prior approval authorities to awardees.

Expiration date.   The end of the performance period for a sponsored award.

Extension.   A delay of the expiration date by the sponsor to the awardee in order to complete the scope of work.  These generally are no-cost (no additional funds provided by the sponsor).

Facilities and Administrative (F&A) costs .  Also referred to as indirect costs, overhead, or administrative costs. These are incurred to conduct normal business activities of the organization receiving support that cannot be readily identified or directly charged to a particular project or activity (e.g., library, depreciation of facilities, heat).

Federal Acquisition Regulations (FAR) .  The policies and procedures for acquisition by federal executive agencies.

FDA .  Food and Drug Administration

FDP .  A cooperative effort among several 10 federal agencies to reduce the administrative burdens associated with research grants and contracts.

Federal Commons .  An on-line grants management system offering grants processing to awardees.  Includes funding opportunities, proposal submission, and award management modules.

Fellowship .  An award directly to an individual rather than an institution.

FIC .  Fogarty International Center (NIH)

Final report.   The technical or financial report required by the sponsor to complete a research project.

Fiscal Year (FY) .  The period for which annual accounts are kept (UVA:  July 1 through June 30; federal government:  October 1 through September 30).

Fixed-price contract/grant.   A contract or grant for which payment is based on a predetermined price, regardless of actual costs.

FOIA .  Freedom of Information Act

Fringe benefits .  Employee benefits paid by the employer. (e.g., FICA, workers’ compensation, medical insurance).  UVA has a negotiated fringe benefits rate with the federal government.

Funding cycle .  Periodic deadlines and review and award dates, which may occur either cyclically or throughout the year.

GCP .  Good Clinical Practices.

Gift .  Awards given with no restrictions specified. Gifts allow the recipient can manage their use, are not associated with deliverables, and are not overseen by the donor.

GLP .  Good Laboratory Practices.

GMP .  Good Manufacturing Practices.

Goldenrod .  UVA’s internal proposal routing form documenting PI assurances and institutional approval.

Governing law .  UVA, as a Virginia state agency, cannot accept a contract governed by the laws of another state or other jurisdiction:  contracts must be governed by the laws of the Commonwealth of Virginia or silent on the governing law.

Grant .  A type of financial assistance awarded to an organization for the conduct of research or other program as specified in an approved proposal. A grant, as opposed to a cooperative agreement, is used whenever the agency anticipates no substantial programmatic involvement during the performance of the activities.

Grant/Contract Officer.   A sponsor’s designee who is responsible for the business management aspects of an award.  In general, this individual works with the project (scientific) officer.

Grantee .  The recipient of a grant.

GSA .  General Services Administration

IACUC (Animal Care and Use Committee) .  An institutional  committee that reviews and approves the use of animal subjects in all research projects. It also oversees institutional animal facilities.

IBC .  Institutional Biosafety Committee

IDC.   Indirect Costs (= F&A costs)

Incremental funding.   A method of funding contracts that by the agency provides specific spending limits below the total estimated cost of the project. These interim limits may be exceeded at the contractor’s own risk.

Indemnification .  An agreement to hold harmless the other party in a contract, from legal actions or claims for damages. State agencies such as UVA cannot indemnify other parties, but can offer insurance clauses.

Indirect cost rate .  The rate established by negotiation with the cognizant federal agency (DHHS for UVA) on the basis of the institution’s projected costs for the year and distributed as prescribed in OMB Circular A-21.  Various rates exist for sponsored research, service, other projects, and on- vs. off-site activities.

Indirect costs .  Also referred to as facilities and administrative costs, overhead, or administrative costs. These are incurred to conduct normal business activities of the organization receiving support that cannot be readily identified or directly charged to a particular project or activity (e.g., library, depreciation of facilities, heating).

In-kind .  Contributions other than money, such as equipment, materials, or services of recognized value.

Institutional Authorized Official .  An individuals authorized by the Board of Regents to sign grants, contracts, and agreements on behalf of The University of Virginia.

Intellectual property (IP) .  Creations of the mind that include inventions, know-how, copyrightable works, or creative or artistic works. Intellectual property may be protected legally via patents, copyrights, and so on, or protected as trade secrets.

Invention .  A process, machine, manufacture, composition of matter, or design, or any new or useful improvement thereof, and any variety of plant which is or may be patentable under the laws of the United States or any other country.

Investigator-initiated proposal.   A submitted proposal that is not in response to an RFP or RFA.

Intergovernmental Personnel Agreement (IPA) .  A mechanism by which state employees may be assigned to work for a federal agency, or vice-versa, while remaining on the payroll of the “home” agency. Often used for a temporary assignment of a faculty member to a federal agency, with the faculty retaining his/her university benefits.

IRB .  Institutional Review Board (charged with ethical review and oversight of human subjects research).

Key personnel.   The personnel considered to be of primary importance to the successful conduct of a research project. The term usually refers to doctoral-level contributors, but may also include other individuals with specialized expertise.  In contracts, replacement of key personnel may require approval of the funding agency.

Letter of intent .  A document advising a funding agency that an application will be submitted in response to a specific solicitation. These letters often are used to guide the creation of a peer review committee.

Limitation of cost (LOC) .  A mandatory clause for cost-reimbursement type contracts stating that the sponsor is not obligated to reimburse the contractor for costs in excess of the stated amount. Similarly, the contractor is not obligated to continue performance once expenses reach the stated amount.

Line item budget .  A budget that lists the cost of individual project personnel and itemizes the costs for all other budgeted categories such as travel, supplies, equipment, etc. Also known as a detailed budget.

Lobbying certification .  An assurance that no federal funds have been used to influence federal officials in the award of a grant or contract.

Matching funds .  Funds obligated by the institution that are required by the granting or contracting agency.

Matching grant.   A grant requiring that a portion of the cost be obtained from other sources.

Materials transfer agreement .  A legally binding document in which one party releases a proprietary reagent, organism, or other item to another party for the purposes of research. It defines the field of use by the recipient and describes the intellectual property rights of sending and receiving parties.

Misconduct in science.   Fabrication, plagiarism, or other practices that seriously deviate from those that are commonly accepted within the scientific community for proposing, conducting, or reporting research. It does not include honest error or honest differences in interpretations or judgments of data.

Modification .  A document changing an existing award, such as approvals to carry over funds among project periods, changes in funding levels or in key personnel, etc.

Modified Total Direct Costs (MTDC) .  For federal awards, these are a subset of direct costs, normally excluding equipment, patient care, space rental, alterations and renovations, and subcontract costs in excess of the first $25,000.  These are the base on which F&A (indirect) costs are calculated.

NACUBO .  National Association of College and University Business Officers

NASA .  National Aeronautics and Space Administration

NCI .  National Cancer Institute (NIH)

NCRR .   National Center for Research Resources (NIH)

NCURA .  National Council of University Research Administrators

NEI .  National Eye Institute (NIH)

New award .  A grant, cooperative agreement, or contract that had not previously been awarded.

New proposal .  Proposals that are submitted to a particular sponsor for the first time.

NHGRI .  National Human Genome Research Institute (NIH)

NHLBI .  National Heart, Lung, and Blood Institute (NIH)

NIA .  National Institute on Aging (NIH)

NIAAA .  National Institute on Alcohol Abuse and Alcoholism (NIH)

NIAID .  National Institute of Allergy and Infectious Diseases (NIH)

NIAMS .  National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIH)

NICHD .  National Institute of Child Health and Human Development (NIH)

NIDA .  National Institute on Drug Abuse (NIH)

NIDCD .  National Institute on Deafness and other Communication Disorders (NIH)

NIDDK .  National Institute of Diabetes and Digestive and Kidney Diseases (NIH)

NIDR .  National Institute of Dental Research (NIH)

NIEHS .  National Institute of Environmental Health Sciences (NIH)

NIGMS .  National Institute of General Medical Sciences (NIH)

NIH .  National Institutes of Health

NIMH .  National Institute of Mental Health (NIH)

NINDS .  National Institute of Neurological Disorders and Stroke (NIH)

NINR .  National Institute for Nursing Research (NIH)

NLM .  National Library of Medicine

No-cost extension .  An extension of the period of performance beyond the expiration data to accomplish the scope of work.  By definition, no additional costs are provided.

Non-competing continuation .  A report on project progress that requests continuation funding for the next portion of the project period.

Non-compliance .  Failure to adhere to applicable regulations, policies, procedures or special conditions related to the conduct of research. These might include unapproved changes in project work scope, use of animals without IACUC approval, and breaches of clinical protocol methodology.

Nondisclosure agreement .  A legal agreement preventing one or both party from disclosing confidential information belonging to the other party.  Also called a confidentiality agreement.

Notice of grant award .  Also called “Notice of award.”  The legally binding document that serves as a notification to the recipient that a grant or cooperative agreement has been made.  The document lists or references the terms of the award and obligates sponsor funds.

NSF .  National Science Foundation

Off-campus .  Sponsored activities, less than 50% of which are conducted on university property or which charge rent to the project as a direct cost.

OHRP .  Office for Human Research Protections (DHHS).  This unit oversees DHHS Regulations for the Protection of Human Subjects (45 CFR 46), and offers guidance on ethical issues in biomedical and behavioral research.

OMB .  Office of Management and Budget.  OMB establishes government grants management policies and guidelines through circulars and common rules.

OMB circulars .  See A-21, A-110, and A-133 above.

On-campus (also on-site) .  Sponsored activities conducted on university property.  In general, when over 50% of such activity takes place within the University, the on-campus F&A rate will be applied to the project.

ONR .  Office of Naval Research

ORI .  Office of Research Integrity (in DHHS).  This office promotes research integrity in projects supported by the PHS, monitors institutional investigations of research misconduct, and facilitates the responsible conduct of research (RCR) through educational, preventive, and regulatory activities.

Patent .  A government grant of the right to stop others from making, using, offering for sale, or selling an invention.

Patent infringement .  Violation of the rights covered by a patent.

Patent prosecution .   Filing of a patent application and the subsequent actions required in order to obtain a granted patent and the maintenance thereof after the award.

Peer review .  A process by which committees of researchers from several institutions review and recommend applications to the funding agency.

Per diem .  A daily allowance paid to personnel working on a sponsored project to cover meals and lodging while traveling.

PHS .  Public Health Service

PHS 2590 .  Application for Continuation of a PHS Grant (National Institutes of Health )

PHS 398 .  Application Form for a PHS Grant (NIH, in the process of being replaced by the SF 424).

PRDA .  Program Research and Development Announcement:  a competitive solicitation for research, development, and related projects in a specified area of interest.

Pre-proposal .  A preliminary proposal of a research project and its estimated budget.  Successful PIs are asked by the sponsor to submit full proposals.

Principal Investigator (PI) .  The individual responsible for the conduct of research or other activity described in a proposal for an award.  The PI has primary responsibility for technical compliance, completion of programmatic work, and fiscal stewardship of sponsor funds.

Prior approval .  The requirement for written sponsor permission for changes in the scope of work, key personnel, use of funds for a project, etc., beyond the original proposal/approval.

Priority score .  A numerical value representing the rating given a proposal by a review committee. Grants are ordered on the basis of their priority scores in order for funding decisions to be made.

Program Announcement.   Notification of a research opportunity that will be available for several years.  Renewed in 3 years at NIH.

Program income .  Gross income earned by the recipient for activities supported by an award.

Program/Project Officer.   A sponsor’s technical officially overseeing an award.  This person works with the Principal Investigator of the awardee and with the sponsor’s grant/contract officer in overseeing the project.

Progress report.   A periodic summary of research progress required by the sponsor.

Project period .  The total time for which support of a project has been approved by the sponsor.

Proposal.   An application for funding including the technical description of the project, personnel, available resources, and funds requested.

Proprietary research .  Sponsored research involving restrictions placed by the sponsor on the distribution or publication of the research findings.

Rebudget .  The movement of funds from one budget category to another.  May require approval of the sponsor’s grant/contract officer.

Regulations .  The contractual rules and procedures governing sponsored research projects.

Renewal .  A competitively reviewed grant and cooperative agreement proposal requesting additional funds extending the scope of work and project period.

Representations and certifications (Reps & Certs) .  Statements of policies, practices, and commitments (e.g., conflict of interest, misconduct in science, debarment/suspension, delinquent federal debt, drug-free workplace, assurances on lobbying) which must be signed as part of some proposals, and especially for federal contract proposals.

Request for Applications (RFA) .  Focused programmatic announcement of a grant opportunity, for a topic of specific interest to a sponsor.  Usually a one-time solicitation, as opposed to a program announcement.

Request for Proposal (RFP) .  Announcement of a contract opportunity that specifies the anticipated area of research, methods to be used, deliverables, and characteristics of allowable applicants (e.g., small business concerns).

Research .  Systematic investigation aimed at the discovery, interpretation, or revision of facts or accepted theories or to make practical applications with the help of such knowledge.

Research, applied .  The systemic, intensive study directed toward producing results that are applicable to a particular problem.

Research, basic .  A systemic, intensive study designed to increase the body of knowledge in a particular field, rather than to develop specific, practical applications.

Responsible conduct of research .  As described by the DHHS Office of Research Integrity, this is comprised of the following components:  honest in conveying information and keeping commitments; accuracy and precision in reporting findings; using resources wisely; avoiding improper bias.

Revised proposal .  A modified request for funding for a project that previously was not funded by the sponsor.

SBIR .  Small Business Innovative Research

Scope of work .  The description of the work to be performed on a research project.

SF 424 .    Standard Form 424 (R&R).

Site visit .  An agency-initiated review of a proposed project conducted at the applicant’s institution.

Small Business Innovative Research (SBIR) .  A program under which a federal agency provides funds to small businesses.

Small Business Technology Transfer (STTR) .  A federal program providing funds to small businesses that are “teamed” with research institutions.

Sole source acquisition .  A procurement that does not provide full and open competition, but rather because one source is available.

Sponsor .  The organization or agency funding research project.

Sponsored project .  A research, training, or service activity supported by an external agency by means of a grant or contract.

Sponsored research .  Research supported by outside sources that is conducted by University employees using any University space or facilities.

SRA .  Society of Research Administrators

Stipend .  A payment made to an individual under a fellowship or training grant in accordance with pre-established levels to provide for the individual’s living expenses during the period of training.  Such individuals are not University employees but are covered by University policies and regulations.

Subcontract, subgrant, or subagreement .  A contract issued under a prime contract, agreement, purchase order, or grant for the procurement of services or program-related tasks over $10,000.  Subcontracts must be consistent with the terms and conditions of the master award, transferring a portion of the research or substantive effort of the prime award to another institution or organization.

Supplemental proposal .  A request to the sponsor for additional funds for an existing project:  may result, for example, from increased costs or changes in project design.

Task order .  A contractual document authorizing work and appropriating funds in a supplement to an existing contract or master agreement.

Teaming agreement .  An agreement between two or more parties to participate in a research teaching activity.

Terms of award .  Requirements imposed by the sponsor on the recipient by policy, statute, or regulations.

Total Direct Costs (TDC) .  The total of all direct costs of a project.

Total project costs .  Also known as total costs.  The allowable direct and indirect costs to carry out an approved project.

Unallowable costs .  Specific expenditures that cannot be charged, directly or indirectly, to federally sponsored agreements.

Unrestricted funds .  Monies with no requirements as to their use or disposition.  Gifts represent such funds.

Unsolicited proposal .  Proposals submitted to a sponsor that are not in response to an RFP or RFA. (See also Investigator-Initiated Proposal.

• Post-award Administration
• Contracts and Clinical Trials Agreements
• Getting Started in Clinical Research
• Intellectual Property (IP) and Entrepreneurial Activities
• Material Transfer Agreements
• Medical Student Research Programs at UVA
• Medical Student Research Symposium
• MSSRP On-Line Preceptor Form
• MSSRP On-Line Student Match Form
• On-line Systems
• Other Medical Student Research Opportunities
• Research: Financial Interest of Faculty
• Review of Proposed Consulting Agreements
• Transfers of NIH/Public Health Service awards
• Unmatched MSSRP projects – 2024
• Research Centers and Programs
• Roles and responsibilities in research administration
• Other Offices Supporting Research
• SBIR and STTR Awards
• Information for students and postdoctoral trainees
• For Research Administrators
• For New Research Faculty
• Funding Programs for Junior Faculty
• NIH for new faculty
• School of Medicine surplus equipment site
• Forms and Documents
• FAQs – SOM offices supporting research
• 2024 Faculty Research Retreat
• Anderson Lecture and Symposia

Why Is Medical Terminology Important?

Medical terminology is the backbone of healthcare communication, promoting accuracy, safety, and efficiency in patient care while facilitating global collaboration and advancing medical science. This standardized language enables healthcare professionals to quickly and accurately assess a patient’s needs and communicate with their care team, resulting in overall better patient outcomes.

The Role of Medical Terminology in Healthcare

Medical terminology serves as the universal language that allows healthcare professionals to communicate effectively and accurately. This language consists of official terms and abbreviations that describe anatomy, bodily functions, diseases, diagnoses, treatments, procedures, and more.

It’s important for healthcare professionals — including physician assistants, occupational therapists, and physical therapists — to learn and understand the formal names for medical conditions and procedures. Many terms are often abbreviated for efficiency, lending an additional collection of acronyms to this universal language.

When Is Medical Terminology Used?

Medical terminology is used extensively and in various contexts throughout the healthcare industry. Not only is it critical in the surgical ward or the emergency room, but it’s also useful for medical receptionists, health insurance agents, health information technicians , and more.

The following are the most common uses for medical terminology:

• Patient care: When used during patient assessments, diagnoses, and treatment planning, medical terminology enables healthcare providers to accurately describe symptoms, conditions, and procedures, ensuring that patient care is well-informed and consistent.
• Medical records: Healthcare facilities maintain detailed medical records for each patient they serve. These records are filled with medical terminology to document a patient’s medical history, medications, lab results, and treatment plans comprehensively.
• Prescriptions: Doctors use medical terminology when writing prescriptions, specifying the medication, dosage, and administration instructions clearly and unambiguously.
• Medical billing: Billing specialists use medical codes to denote conditions, medications, and treatments for a patient’s insurance provider, ensuring that the patient is covered or billed accordingly for the care they receive.
• Consultations and referrals: When physicians consult with specialists or refer patients to other healthcare providers, they rely on medical terminology to convey vital and accurate information about the patient’s condition and requirements.
• Medical imaging: Radiologists and other healthcare technicians use medical terminology to describe findings on X-rays, MRIs, CT scans, and other imaging studies, ensuring precise reporting and treatment recommendations.
• Medical research: Scientists and researchers use medical terminology in scholarly articles, clinical trials, and research papers to share their findings with colleagues and contribute to the global body of medical knowledge.
• Education and training: Medical terminology is a fundamental component of healthcare education. It equips students with the vocabulary needed to understand and communicate effectively in clinical settings.
• Health information systems: Electronic health records (EHRs) and healthcare IT systems rely heavily on medical terminology for data input, retrieval, and exchanges between healthcare providers and facilities.

Who Needs to Understand Medical Terminology?

Of course, it’s critical for doctors, nurses, and those in other clinical roles to understand medical terminology so they can administer proper care and communicate with their colleagues. Aspiring medical practitioners are almost always required to be proficient in medical terminology for admission into graduate programs. It’s even important for some non-clinical healthcare professionals to become familiar with common terms.   

Looking to deepen your knowledge? Check out our Medical Terminology course! >

The following individuals are typically required (or at least strongly encouraged) to learn medical terminology.

Clinical roles:

• General practitioners
• Physician assistants
• Medical trainees
• Occupational therapists
• Physical therapists
• Emergency medical technicians (EMTs)
• Emergency responders (911 operators)
• Nursing students & aides
• Social workers
• Home healthcare providers

Non-clinical roles:

• Medical receptionists / office managers
• Medical researchers
• Pharmacists
• Insurance companies
• Billing specialists
• Medical coders
• Healthcare informaticists
• Medical compliance officers

It’s typically not necessary for patients to understand medical terminology; doing so will not affect their care. However, some patients like to understand what certain terms or abbreviations indicate on their charts or in their records, since it helps them feel more engaged in their own care, which can contribute to increased compliance. 

A MEDICAL TERMINOLOGY COURSE IS VALUABLE TO YOUR CAREER

Taking a medical terminology course is a great first step to equip you with the skills and knowledge you’ll need to be successful.

Examples of Medical Terminology

Often, when we talk about health conditions in a non-clinical setting, we use common terms that might describe a collection of symptoms, rather than the formal name for a specific disease, condition, or type of injury. For example, you might tell a coworker that you were out sick with a cold and a bad sore throat; your healthcare provider would have recorded that you had an upper respiratory tract infection (URI) with acute pharyngitis.

Medical terms usually consist of a root word, a prefix, and/or a suffix that lends specificity to the description of a health condition. Many terms originate from Greek or Latin, which is why they might sound unfamiliar or obscure to the untrained ear. Once you become familiar with enough common prefixes, roots, and suffixes, you can begin to understand how the language of medicine is constructed.

Here are five examples of common medical terms, defined and broken into their discrete parts:

• pharyng- = pharynx, or throat
• -itis = disease or inflammation
• ante = before
• cibum = food
• intra- = within
• -venous = relating to a vein
• myo- = muscle
• -cardial = of the heart
• infarction = tissue death
• append- = appendix
• -ectomy = removal

Importance of Knowing Medical Terminology

The ability for all members of a healthcare team to understand and communicate using medical terminology is important for a number of reasons:

It promotes clarity and precision.

Medical terminology eliminates ambiguity by providing precise words and phrases to describe conditions and procedures. This clarity is vital to prevent misunderstandings that could have serious consequences for both patients and care providers.

It standardizes healthcare around the world.

Healthcare is a global industry, and standardized medical terminology ensures that professionals worldwide can understand each other. This is especially important in today’s interconnected healthcare systems.

It supports efficiency.

In fast-paced healthcare settings, concise and standardized language helps healthcare providers save time. It allows for quick, accurate documentation of patient information and facilitates efficient communication between care team members.

It ensures patient safety.

Medical terminology helps prevent errors in diagnoses and treatments by ensuring that everyone involved in a patient’s care understands the same information, reducing the risk of mistakes.

It contributes to furthering medical research.

Medical terminology is the foundation of medical literature and research. It enables healthcare professionals to access, understand, and contribute to ever-expanding medical knowledge.

It supports career advancement.

As with any type of professional and continuing education, building your medical terminology skills can lead to promotions and increase your hireability in the healthcare field. Even if you don’t work in a clinical role, being able to list this as a skill on your resume can make you stand out as a particularly valuable asset.

How to Improve Your Medical Terminology Skills

If you are an aspiring doctor, nurse, physician’s assistant, physical or occupational therapist, or even veterinary student, medical terminology is a cornerstone of your profession, and is a skill you will likely need to advance to graduate school. The good news (especially if you are a non-clinical healthcare worker) is that you do not need to attend medical or nursing school to become proficient in medical terminology.

Courses are available through many colleges and universities, often in a convenient online format. The online Medical Terminology course from the University of San Diego (USD) School of Professional and Continuing Education, for example, is a self-paced course that gives students six months to complete all units. You may also be able to find medical terminology courses through local trade schools, adult education programs, training manuals and textbooks, and even trade publications.

Proficiency in medical terminology can open up many new career possibilities — plus, it helps both clinical and non-clinical professionals become stronger members of their teams. For more convenient, practical continuing education programs, explore USD’s catalog of healthcare courses and certificates .

Where can I learn medical terminology?

Medical terminology courses are available through many colleges and universities, often in a convenient online format. You may also be able to find medical terminology courses through local trade schools, adult education programs, training manuals and textbooks, and even trade publications.

Who needs to know medical terminology?

Doctors, nurses, and other medical professionals must learn medical terminology so they can administer proper patient care and communicate with their colleagues. Additionally, many non-clinical roles are typically required (or at least strongly encouraged) to learn common terms, including healthcare informaticists, billing specialists, medical receptionists, pharmacists, medical researchers, and healthcare compliance officers.

Curriculum covered in this article

Start your medical terminology course today..

Become Versed in Medical Language and Terminology

Start date:

Start now, you have 180 days to complete this course once enrolled

What you will learn:

• List, define and identify medical terms for different body systems, as well as the components of these terms
• Identify the most common word parts for medical terms
• Interpret important medical, diagnostic and laboratory abbreviations and terms
• Construct medical terms using root words, combining forms, prefixes and suffixes
• Distinguish between singular and plural forms of selected medical terms
• Classify word parts for medical terms for numbers, positions and directions

Be Sure To Share This Article

• Share on Twitter
• Share on Facebook
• Share on LinkedIn

Your health care career

Improve your medical terminology, mental health, and more with 100% online courses.

Related Posts

Warning: The NCBI web site requires JavaScript to function. more...

An official website of the United States government

The .gov means it's official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings
• Browse Titles

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

Institute of Medicine (US) Committee on Strategies for Small-Number-Participant Clinical Research Trials; Evans CH Jr., Ildstad ST, editors. Small Clinical Trials: Issues and Challenges. Washington (DC): National Academies Press (US); 2001.

Small Clinical Trials: Issues and Challenges.

• Hardcopy Version at National Academies Press

Appendix B Glossary of Statistical and Clinical Trials Terms

Dorland's Illustrated Medical Dictionary , 28th edition . 1994 . Philadelphia : W. B. Saunders .

Eddy, D. M. , V. Hasselblad , and R. Shacther . 1992 . Meta-Analysis by the Confidence Profile Method . San Diego : Academic Press .

Everitt, B. S. 1995 . The Cambridge Dictionary of Statistics in the Medical Sciences . Cambridge, United Kingdom : Cambridge University Press .

Hirsch, R. P. , and R. Riegelman . 1996 . Statistical Operations . Analysis of Health Research Data . Cambridge, MA : Blackwell Science .

Last, J. M. , ed. 1995 . A Dictionary of Epidemiology . Oxford : Oxford University Press .

The set of values of a test statistic for which the null hypothesis is not rejected.

A sampling method by which the sample is taken from groups or batches as they pass a specified time point, e.g., age, followed by sampling of individuals within the sampled groups.

The late clinical stage of infection with human immunodeficiency virus ( HIV ), recognized as a distinct syndrome in 1981.The surveillance definition includes HIV-infected persons who have less than 200 CD4 + T lymphocytes per μL or a CD4 + T lymphocyte percentage of total lymphocytes of less than 14 percent, accompanied by any of 26 clinical conditions (e.g., opportunistic infection, Kaposi's sarcoma, wasting syndrome).

A procedure in which an initial set of subjects is selected by a sampling procedure and, whenever the variable of interest of a selected subject satisfies a given criterion, additional subjects whose values are in the neighborhood of those for that subject are added to the sample.

A sampling procedure in which the selection process depends on the observed values of some variables of interest.

A term used when the effect of administering two treatments together is the sum of their separate effects.

A model in which the combined effect of several factors is the sum of the effects that would be produced by each of the factors in the absence of the others.

A procedure for summarization of a statistical measure in which the effects of differences in composition of the population being compared have been minimized by statistical methods. Examples are adjustment by regression analysis and by standardization. See standardization.

An undesirable or unwanted consequence experienced by a subject during a clinical trial irrespective of the relationship to the study treatment.

A procedure for adjusting rates, e.g., death rates, designed to minimize the effects of differences in age composition when comparing rates for different populations.

Any systematic process that consists of an ordered sequence of steps in which each step depends on the outcome of the previous one.

An explicit description of steps to be taken in patient care in specified circumstances.

(α) The probability of a Type I error . The value of a is usually 0.05. See significance level.

The hypothesis against which the null hypothesis is tested.

An extension of the analysis of variance that allows consideration of the possible effects of covariates on the response variable, in addition to the effects of the factor or treatment variables. The covariates are assumed to be unaffected by treatments, and in general, their relationship to the response is assumed to be linear.

A statistical technique that isolates and assesses the contributions of categorical independent variables to variations in the mean value of a continuous dependent variable. The total variance of a set of observations are partitioned according to different factors, e.g., sex, age, treatment groups, and compared by way of F tests. Differences between means can then be assessed.

A sampling method in which a geographical region is subdivided into smaller areas (counties, villages, city blocks, etc.), some of which are selected at random, and the chosen areas are then subsampled or completely surveyed. See cluster sampling.

A useful way of summarizing the information from a series of measurements made on an individual over time or for a doseresponse curve. Calculated by adding the areas under the curve between each pair of consecutive observations, using for example, the trapezium rule.

The sum of all the values in a set of measurements divided by the number of values in the set.

The treatment designated to be given to a patient in a clinical trial as indicated at the time of enrollment.

Statistical dependence between two or more events, characteristics, or other variables. Most often applied in the context of binary variables forming a two-by-two contingency table. A positive association between two variables exists when the occurrence of higher values of a variable is associated with the occurrence of higher values of another variable. A negative association exists when the occurrence of higher values of one variable is associated with lower values of the other variable.

The conditions under which statistical techniques give valid results.

The cumulative incidence of a disease or condition in a particular group, during a limited period of time, or under special circumstances such as an epidemic.

The loss of subjects over the period of a longitudinal study. See missing values.

An average value represents or summarizes the relevant features of a set of values, and in this sense the term includes the median and the mode.

An experimental design in which the same number of observations is taken for each combination of the experimental factors.

A graphical representation for displaying discrete data organized in such a way that each observation can fall into one and only one category of the variable. Frequencies are listed along one axis, and categories of the variable are listed along the other axis. The frequencies of each group of observations are represented by the lengths of the corresponding bars. See histogram.

A set of data collected at the beginning of a study.

The shape taken by the hazard rate for the event of death in humans. It is relatively high during the first year of life, decreases fairly soon to a minimum, and begins to climb again sometime around ages 45 to 50.

An interval of a posterior distribution such that the density at any point inside the interval is greater than the density at any point outside. For any probability level, there is generally only one such interval, which is often known as the highest posterior density region.

Statistical inference based on Bayes's theorem . The focus of the Bayesian approach is the probability distribution of any unknowns, given available information. The process deals with probabilities of hypotheses and probability distributions of parameters, which are not taken into account in classical statistical inference.

A probability distribution having the overall shape of a vertical cross-section of a bell. Examples are normal distribution and Student's t distribution.

The ratio of net present value of measurable benefits to costs. Calculation of a benefit-cost ratio is used to determine the economic feasibility or success of a program.

The probability of a Type II error .

Deviation of results or inferences from the truth or processes leading to such a deviation. Any trend in the collection, analysis, interpretation, publication, or review of data that can lead to conclusions that are systematically different from the truth. Statistical bias occurs when the extent to which the statistical method used in a study does not estimate the quantity thought to be estimated or does not test the hypothesis to be tested.

A probability distribution or a frequency distribution with two modes.

A sequence whose elements take one of only two possible values, usually denoted 0 or 1.

A variable having only two possible values, usually labeled 0 or 1. Data involving this type of variable often require specialized statistical techniques such as logistic regression.

The probability distribution of the number of occurrences of a binary event in a sample of n independent observations. The distribution is associated with two mutually exclusive outcomes, e.g., death or survival, success or failure.

The quantitative evaluation of the potency of a substance by assessing its effects on tissues, cells, live experimental animals, or humans.

The degree to which clinically important outcomes of treatment by a new preparation resemble those of a previously established preparation.

Trials carried out to compare two or more formulations of a drug containing the same active ingredient to determine whether the different formulations give rise to comparable levels in blood.

The effect of treatment for all persons who receive the therapeutic agent to which they were assigned. It measures the biological action of a treatment among compliant persons.

The criterion that an observed, presumably or putatively causal association fits previously existing biological or medical knowledge.

The application of statistical methods to the study of numerical data on the basis of observations of biological phenomena.

The application of statistical methods to biological and medical problems.

A graphical display of multivariate data designed to show any structure, pattern, or relationship between variables.

A unit of information consisting of one binary digit.

Data in which the subjects each have measurements on two variables.

The joint distribution of two random variables, x and y.

A procedure used in clinical trials to avoid the possible bias that might be introduced if the patient or doctor, or both, knew which treatment the patient would be receiving. A trial is double blind if both patient and doctor are not aware of treatment given; if either the doctor or the patient is not aware of treatment given, the trial is single blind. Also called masking.

A term used in experimental design to refer to a homogeneous grouping of experimental units designed to enable the experimenter to isolate and, if necessary, eliminate variability due to extraneous causes.

A random allocation procedure used to keep the numbers of subjects in the different groups of a clinical trial closely balanced at all times.

Varieties of tests using electrophoresis, nucleic acid base pairing, or protein-antibody interaction to detect and identify DNA or RNA in samples. The Southern blot is used to identify a specific segment of DNA in a sample. The Northern blot detects and identifies samples of RNA. The Western blot is widely used in a test for detection of human immunodeficiency virus infection.

A data-based simulation method for statistical inference that can be used to study the variability of estimated characteristics of the probability distribution of a set of observations and provide confidence intervals for parameters in situations in which these are difficult or impossible to derive in the usual way.

A procedure for guarding against an increase in the Type I error when performing multiple significance tests. To maintain the Type I error at some selected value, a, each of the m tests to be performed is judged against a significance level, a/m. This method is acceptable for a small number of simultaneous tests to be performed (up to five).

The relating of causes to the effects that they produce. A cause is termed “necessary” when it must always precede an effect. This effect need not be the sole result of the one cause. A cause is termed “sufficient” when it inevitably initiates or produces an effect. Any given cause may be necessary, sufficient, neither necessary nor sufficient, or both necessary and sufficient.

Observation with an unknown value due to the occurrence of an event (e.g., death, loss to follow-up, or termination of study) before the occurrence of the event of interest in the study.

The tendency for the sampling distribution of means to be a normal (Gaussian) distribution, even if the data do not have a Gaussian distribution , for sufficiently large numbers of subjects.

The range within which the central 90 percent of values of a set of observations lie.

A property of the distribution of a variable usually measured by statistics such as the mean, median, and mode.

In genetics, the presence in an individual of cells of different origin, such as of blood cells derived from a dizygotic cotwin.

The probability distribution of the sum of squares of a number of independent standard normal variables.

Any statistical test based on comparison of a test statistic to a chi-square distribution. The most common chi-square tests (e.g., the Mantel-Haenszel and Pearson chi-square tests) are used to detect whether two or more population distributions differ from one another. These tests usually involve counts of data and may involve comparison of samples from the distribution under study or comparison of a sample to a theoretically expected distribution.

A test applied to a two-dimensional contingency table in which one variable has two categories and the other has k ordered categories to assess whether there is a difference in the trend of the proportions in the two groups.

A procedure designed to provide insight into the structure of a clinical problem and to identify the main determinants of diagnostic and therapeutic choice. This procedure is useful to small numbers of clinical cases, even to a single patient (see n -of-1 study). The procedure has four stages: 1. Definition of the clinical problem and structuring it as a decision tree. This includes description of the patient, of the possible diagnostic and therapeutic actions, and of the possible outcomes after treatment. 2. Estimation of probabilities for diagnostic and therapeutic outcomes. 3. Performance of the requisite computations for determination of the preferred course of action. 4. Presentation of the results of the analysis in a clinically useful way.

Epidemiological study conducted in a clinical setting, usually by clinicians, with patients as the subjects of study. It uses the information from classic epidemiology to aid decision making about identified cases of disease.

A prospective study that involves human subjects, designed to determine the effectiveness of a treatment, a surgical procedure, or a therapeutic regimen administered to patients with a specific disease. Clinical trials have four phases:

Safety and pharmacologic profiles. This involves the initial introduction of a candidate vaccine or drug into a human population to determine its safety and mode of action. In drug trials, this phase may include studies of dose and route of administration. Phase I trials usually involve less than 100 healthy volunteers.

Pilot efficacy studies. This initial trial aims to examine efficacy in about 200 to 500 volunteers. The focus of vaccine trials is immunogenicity, whereas with drugs the focus is on the demonstration of safety and efficacy in comparison with those of other existing regimens. Often, subjects are randomly allocated to study and control groups.

Extensive clinical trial. This phase aims to complete assessment of safety and efficacy. It involves large numbers, possibly thousands, of volunteers from one center or many centers (a multicenter trial), usually with random allocation to study and control groups.

This phase is conducted after the national drug registration authority (the Food and Drug Administration in the United States) has approved the drug for distribution or marketing. The trial is designed to determine a specific pharmacological effect or the effects of long-term use or to establish the incidence of adverse reactions. Ethical review is required in phase IV trials.

The distinction between results in terms of their possible clinical importance rather than simply in terms of their statistical significance. For example, very small differences that have little or no clinical importance may turn out to be statistically significant. The implications of any finding in a medical investigation must be judged on both clinical and statistical grounds.

The study of indices and rating scales used to describe or measure symptoms, physical signs, and other clinical phenomena in clinical medicine.

See sequential analysis.

A set of statistical methods for constructing a sensible and informative classification of an initially unclassified set of data using the variable values observed on each individual or item.

A sampling method in which each unit (cluster) selected is a group of persons (all persons in a city block, a family, a school, or a hospital) rather than an individual.

A formal statement of desirable conduct that research workers or practitioners are expected to honor. Examples are the Hippocratic Oath, the Nuremberg Code, and the Helsinki Declaration.

A measure of the agreement among several rankings or categories.

The square of the correlation coefficient between two variables. It gives the proportion of the variation in one variable that is accounted for by the other.

A measure of spread for a set of data, defined as 100 x standard deviation / mean. Originally proposed as a way of comparing the variability in different distributions but found to be sensitive to errors in the mean.

Very high correlation between variables. See multicollinearity.

A disease(s) that coexist(s) in a study participant in addition to the index condition that is the subject of study.

The probability that event A occurs given the outcome of some other event, event B ; usually written P (A|B). Conditional probabilities obey all the axioms of probability theory. See Bayes's theorem .

The computed interval with a given probability, e.g., 95 percent, that the true value of a variable such as a mean, proportion, or rate is contained within the interval.

The upper and lower boundaries of the confidence interval.

A method of meta-analysis that uses a set of quantitative techniques that include parameters, functions, and prior distributions (in a Bayesian application). Its goal is to use evidence to derive maximum likelihood estimates and covariances (in a non-Bayesian application) or joint probability distributions (in a Bayesian application) for parameters of interest. Distributions and estimates can be used to make decisions about interventions or calculations of other parameters or to plan research to gather additional information about any parameter.

A process observed in some factorial designs in which a measure of the effect of an exposure on risk is distorted because of the association of the exposure with some other factor(s) that influences the outcome under study.

A variable that can cause or prevent the outcome of interest, is not an intermediate variable, and is associated with the factor under investigation.

A tabular cross-classification of data such that subcategories of one characteristic are indicated horizontally (in rows) and subcategories of another characteristic are indicated vertically (in columns). The simplest contingency table is the fourfold or two-by-two table analyzed by using the chi-square statistic. Three- and higher-dimensional tables are analyzed by using log-linear models.

An approach that applies Bayesian inference to determine the maximum tolerated dose in a phase I trial. The method begins by assuming a logistic regression model for the dosetoxicity relationship and a prior distribution for the parameters. After each patient's toxicity result becomes available, the posterior distribution of the parameters is recomputed and used to estimate the probability of toxicity at each of a series of dose levels.

Subjects with whom comparison is made in a case-control study, randomized controlled trial, or some other variety of epidemiological study.

A phase III clinical trial in which an experimental treatment is compared with a control treatment, the latter being either the current standard treatment or a placebo.

Statistics calculated from sample values X 1 , X 2 , . . . , X n that elicit information about some characteristic of a process that is being monitored.

The degree to which variables change together.

An index that quantifies the linear relationship between a pair of variables. The coefficient takes values between −1 and 1, with the sign indicating the direction of the relationship and the numerical magnitude indicating its strength. A value of zero indicates the lack of any linear relationship between two variables.

A square, symmetric matrix with rows and columns corresponding to variables in which the off-diagonal elements are correlations between pairs of variables and the elements on the main diagonal are unity.

An economic analysis in which the costs of medical care and the benefits of reduced loss of net earnings due to the prevention of premature death or disability are considered. The general rule for the allocation of funds in a cost-benefit analysis is that the ratio of marginal benefit (the benefit of preventing an additional case) to marginal cost (the cost of preventing an additional case) should be equal to or greater than 1.

A method that allows the hazard function to be modeled on a set of explanatory variables without making restrictive assumptions about the dependence of the hazard function on time. Estimates of the parameters in the model, i.e., β 1 , β 2 , . . ., β p , are usually obtained by maximum likelihood estimation and depend only on the order in which events occur, not on the exact time of their occurrences.

The values of a test statistic that lead to rejection of a null hypothesis. The size of the critical region is the probability of obtaining an outcome belonging to this region when the null hypothesis is true, i.e., the probability of a Type I error . See also acceptance region.

The value with which a statistic calculated from sample data is compared to determine whether a null hypothesis should be rejected. The value is related to the particular significance level chosen.

The division of data into two subsets of approximately equal size, one of which is used to estimate the parameters in some model of interest and the other of which is used to assess whether the model with these parameter values fits adequately.

A listing of the sample values of a variable together with the proportion of the observations less than or equal to each value.

An approach that involves identification of all available choices and the potential outcomes of each in a series of decisions that must be made about aspects of patient care: diagnostic procedures, therapeutic regimens, and prognostic expectations. The range of choices can be plotted on a decision tree, where at each branch or decision node the probabilities of each outcome are displayed.

A concept used in decision analysis that tells the experimenter how to conduct the statistical aspects of an experiment and what action to take for each possible outcome. See also loss function.

A graphical representation of the alternatives available at each stage in the process of decision making, where decision options are represented as branches and subsequent possible outcomes are represented as further branches. The decisions and the eventualities are presented in the order in which they are likely to occur. The junction at which a decision must be taken is called a “decision node.”

The number of independent units of information in a sample relevant to the estimation of a parameter or calculation of a statistic. For example, in a contingency table it is one less than the number of row categories multiplied by one less than the number of column categories. Also used to refer to a parameter of various families of distributions, such as chi-square, Student's t , and F distributions.

A variable whose value is dependent on the effect of another variable(s)—an independent variable(s)—in the relationship under study. In statistics, it is the variable predicted by a regression equation.

A general term for methods of summarizing and tabulating data that make their main features more transparent, for example, calculating means and variances and plotting histograms.

A measure of the extent to which a particular model differs from the saturated model for a data set.

Synonym for binary variable.

The direction of inference of a study, i.e., retrospective or prospective, or of the relationship between variables, such as a negative or a positive association indicated by a correlation coefficient.

Variables having only integer values, e.g., number of births or number of pregnancies.

A statistical analytical technique used on multivariate data that aims to assess whether or not a set of variables distinguish or discriminate between two (or more) groups of individuals. It separates sets of observed values and allocates new values from two (or more) discrete populations to the correct population with minimal probability of classification.

The complete summary of the frequencies of the values or categories of a measurement obtained for a group of persons. It tells either how many or what proportion of the group was found to have each value (or each range of values) out of all the possible values that the quantitative measure can have.

A function that gives the relative frequency with which a random variable falls at or below each of a series of values. Examples include normal distribution, lognormal distribution, chi-square distribution, t distribution, F distribution, and binomial distribution.

A clinical trial, usually undertaken at a late stage in the development of a drug, to obtain information about the appropriate magnitude of initial and subsequent doses. Most common is the parallel-dose design, in which one group of subjects is given a placebo and other groups are given different doses of the active treatment.

A plot of the values of a response variable against the corresponding values of the dose of drug received or level of exposure endured.

A relationship in which a change in amount, intensity, or duration of exposure is associated with a change—either an increase or a decrease—in the risk of a specified outcome.

A procedure of blind assignment to study and control groups and blind assessment of outcome, designed to ensure that ascertainment of outcome is not biased by knowledge of the group to which an individual was assigned. Double refers to both subjects or patients and observers or clinicians.

The variables resulting from recording of categorical variables with more than two categories into a series of binary variables.

A quantity that measures the effect of a factor on the frequency or risk of health outcome. Three such measures are attributable fractions, which measure the fraction of cases due to a factor; risk and rate differences, which measure the amount a factor adds to the risk or rate of a disease; and risk and rate ratios, which measure the amount by which a factor multiplies the risk or rate of disease.

A factor that modifies the effect of a putative causal factor under study. For example, age is an effect modifier for many conditions, and immunization status is an effect modifier for the consequences of exposure to pathogenic organisms. Effect modification is detected by varying the selected effect measure for the factor under study across levels of another factor.

The effect of a treatment relative to the effect a control treatment in the ideal situation in which all persons fully comply with the treatment regimen to which they were assigned by random allocation.

A clearly defined outcome or event associated with an individual in a medical investigation. An example is the eath of a patient.

A state of genuine uncertainty about the benefits or harms that may result from each of two or more regimens. A state of equipoise is an indication for a randomized controlled trial because there are no ethical concerns about one regimen being better for a particular patient.

The error of rejecting a true null hypothesis, i.e., declaring that a difference exists when it does not.

The error of failing to reject a false null hypothesis, i.e., declaring that a difference does not exist when in fact it does.

Either a single number (point estimate) or a range of numbers (interval estimate) which is inferred to be plausible for some parameter of interest.

The process of providing a numerical value for a population parameter on the basis of information collected from a sample. If a single figure for the unknown parameter is calculated, the process is called “point estimation.” If an interval within which the parameter is likely to fall is calculated, the procedure is called “interval estimation.”

A statistical method based on the actual, i.e., “exact,” probability distribution of the study data rather than on an approximation such as the normal or chi-square distribution, e.g., Fisher's exact test .

A study in which conditions are under the direct control of the investigator. A population is selected for a planned trial of a regimen whose effects are measured by comparing the outcome of the regimen in the experimental group with the outcome of another regimen in a control group. Clinical trials fall under this heading.

A clinical trial designed to explain how a treatment works.

A term that is used in a variety of ways in statistics but that is most commonly used to refer to a categorical variable, with a smaller number of levels, under investigation in an experiment as a possible source of variation.

A set of statistical methods for analysis of the correlations among several variables to estimate the number of fundamental dimensions that underlie the observed data and to describe and measure those dimensions.

A method of setting up an experiment or study to ensure that all levels of each intervention or classificatory factor occur with all levels of the others and that their possible interactions are investigated. The simplest factorial design is one in which each of two treatments or interventions is either present or absent so that subjects are divided into four groups: those receiving neither treatment, those receiving only the first treatment, those receiving only the second treatment, and those receiving both treatments.

The proportion of cases in which a diagnostic test indicates that a disease is absent from patients who have the disease.

The proportion of cases in which a diagnostic test indicates that a disease is present in disease-free patients.

The probability distribution of the ratio of two independent random variables, each having a chi-square distribution, divided by their respective degrees of freedom.

A scheme designed to estimate the maximum tolerated dose during a phase I clinical trial, using as few patients as possible. Using the National Cancer Institute standards for adverse drug reactions, the procedure begins patient accrual with three patients at an initial dose level and continues at each subsequent dose level until at least one toxicity of grade 3 or above is encountered. Once the latter occurs, three additional patients are entered at that level and six patients are entered into each succeeding level. The search scheme stops when at least two of six patients have toxicities of grade >3.

The test for association in a two-by-two table that is based upon the exact hypergeometric distribution of the frequencies within the table. The procedure consists of evaluating the sum of the probabilities associated with the observed table and all possible two-by-two tables that have the same row and column totals as the observed data.

The inverse of the variance-covariance matrix of a set of parameters.

A term used to describe comparisons made within a data set not specifically prescribed before the start of the study.

Refers to the value of the response variable predicted by some estimated model.

A method of summarizing a set of observations by using the minimum value, the lower quartile, the median, upper quartile, and maximum value. Forms the basis of the box-and-whisker plot.

The effects attributable to a finite set of levels of a factor that are of specific interest. For example, the investigator may wish to compare the effects of three particular drugs on a response variable.

A model that contains only factors with fixed effects.

See distribution.

A test for the equality of the variances of two populations having normal distributions, based on the ratio of the variances of a sample of observations taken from each. Commonly used in the analysis of variance, in which testing of whether particular variances are the same also tests for the equality of a set of means.

A quality, trait, or fact that is so related to another as to be dependent upon and to vary with this other.

The relationship between the true values of variables, i.e., the values obtained under the assumption that the variables were measured without error.

A plotting device used in meta-analysis to detect publication bias. The estimate of risk is plotted against sample size. If there is no publication bias, the plot is funnel-shaped. Publication bias, in which studies with significant results are more likely to be published than those with small or no significant effects, removes part of the lower left hand corner of the funnel.

A bell-shaped frequency distribution of infinite range of a random variable. All possible values of the variable are displayed on the horizontal axis. The frequency (probability) of each value is displayed on the vertical axis, producing the graph of the distribution. The properties are as follows: (1) it is a continuous, symmetrical distribution; both tails extend to infinity; (2) the arithmetic mean, mode, and median are identical; and (3) its shape is completely determined by the mean and standard deviation. Another name for normal distribution.

A class of models that arise from a natural generalization of ordinary linear regression. The function of the expected value of the response variable, y, is modeled as a linear combination of the explanatory variables, X 1 , X 2 , . . ., . X q . The other components of such models are a specification of the form of the variance of the response variable and of its probability distribution.

Degree of agreement between an empirically observed distribution and a mathematical or rhetorical distribution.

Measures of the agreement between a set of sample observations and the corresponding values predicted from some model of interest. Examples are chi-square statistic, deviance, and likelihood ratio.

A plot for diagnosing model inadequacy or revealing the presence of outliers, in which the absolute values of, e.g., the residuals from a multiple regression are plotted against the quantiles of the standard normal distribution. Outliers will appear at the top right of the plot as points that are separated from the others, whereas systematic departures from a straight line could indicate that the model is unsatisfactory.

The probability that an individual experiences an event (death, improvement, etc.) in a small time interval, given that the individual has survived up to the beginning of the interval. It is a measure of how likely an individual is to experience an event as a function of the age of the individual. The hazard function may remain constant, increase, or decrease. See also survival function and bathtub curve.

A theoretical measure of the risk of occurrence of an event, e.g., death or a new disease, at a point in time, t , defined mathematically as the limit, as Δ t approaches zero, or of the probability that an individual well at time t will experience the event by t + Δ t , divided by Δ t .

A procedure for modeling the hazard rate that does not depend on the assumptions made in Cox's proportional hazards model , namely, that the loghazard function is an additive function of both time and the vector of covariates.

Nonconstancy of the variance of a measure over the levels of the factors under study.

A graphical representation of a set of observations, in which class frequencies are represented by the areas of rectangles centered on the class interval.

Constancy of the variance of a measure over the levels of the factors under study.

The pathogenic organism responsible for acquired immunodeficiency syndrome ( AIDS ).

Antigens on cell surfaces that are important for foreign antigen recognition and that play a role in the coordination and activation of the immune response.

The exact probability distribution of the frequencies in a two-by-two contingency table, conditional on the marginal frequencies being fixed at their observed levels. Usually approximated by the binomial distribution.

One of (perhaps) several variables that appear as arguments in a regression equation.

A variable that takes only one of two possible values, with one (usually 1) indicating the presence of a condition and the other (usually 0) indicating the absence of the condition. Used mainly in regression analysis.

Censored observations that occur for reasons related to treatment, e.g., when treatment is withdrawn as a result of a deterioration in the physical condition of a patient.

A term used in the context of Bayesian inference to indicate a prior distribution that reflects empirical or theoretical information regarding the value of an unknown parameter.

The voluntary consent given by a patient to participate in, usually, a clinical trial after being informed of its purpose, method of treatment, procedure for assignment to treatment, benefits and risks associated with participation, and required data collection procedures and schedule.

The first phase in the examination of a data set that consists of a number of informal steps, including checking the quality of the data, calculating simple summary statistics, and constructing appropriate graphs. The general aim is to clarify the structure of the data, obtain a simple descriptive summary, and possibly get ideas for a more sophisticated analysis.

Synonym for hazard function.

A procedure in which all patients randomly allocated to a treatment in a clinical trial are analyzed together as representing that treatment, whether or not they received or completed the prescribed regimen. Failure to follow this step defeats the main purpose of random allocation and can invalidate the results.

The interdependent operation of two or more causes to produce or prevent an effect.

Analysis made before the planned end of a clinical trial, usually with the aim of detecting treatment differences at an early stage and thus preventing as many patients as possible from receiving an “inferior” treatment.

A variable that occurs in a causal pathway from an independent to a dependent variable. It causes variation in the dependent variable and is caused to vary by the independent variable. Its value is altered to block or alter the effect(s) of another factor. Such a variable is statistically associated with both the independent and the dependent variables.

A measure of spread given by the difference between the first and third quartiles of a sample.

A study in which a single group of subjects is measured several times before and after some event or manipulation. Also used to describe investigation of a single subject. See n -of-1 clinical trials.

Observations that often arise in the context of studies of time elapsed to a particular event when subjects are not monitored continuously. Instead, the prior occurrence of the event of interest is detectable only at specific times of observation, e.g., at the time of medical examination.

An investigation involving intentional change in some aspect of the status of the subjects, e.g., introduction of a preventive or therapeutic regimen, to test a hypothesis. Usually it is an experiment such as a randomized clinical trial.

A two-stage procedure in which the samples from the original bootstrap population are themselves bootstrapped. The technique can give confidence intervals of more accurate coverage than simple bootstrapping.

The successive repetition of a mathematical process, using the result of one stage as the input for the next.

A technique for estimating the variance and the bias of an estimator. If the sample size is n , the estimator is applied to each subsample of size n − 1, obtained by dropping a measurement from analysis. The sum of squared differences between each of the resulting estimates and their mean, multiplied by ( n − 1) /n, is the jackknife estimate of variance; the difference between the mean and the original estimate, multiplied by ( n − 1), is the jackknife estimate of bias.

A nonparametric method of compiling life or survival tables. This combines calculated probabilities of survival and estimates to allow censored observations, which are assumed to occur randomly. The intervals are defined as ending each time that an event, (e.g., death or withdrawal) occurs and are therefore unequal.

A chance corrected index of the agreement between, e.g., judgments and diagnoses made by two raters. Calculated as the ratio of the observed excess over chance agreement to the maximum possible excess over chance, the coefficient takes the value unity when there is perfect agreement and the value zero when observed agreement is equal to chance agreement.

Measures of the correlation between two sets of rankings. Kendall's tau statistic is a rank correlation coefficient based on the number of inversions in one ranking compared with the number of inversions in another, e.g., on S , given by S = P − Q, where P is the number of concordant pairs of observations, that is, pairs of observations such that their rankings on the two variables are in the same direction, and Q is the number of discordant pairs for which rankings on the two variables are in the reverse direction.

A distribution-free method that is the analogue of the analysis of variance of a one-way design. It tests whether the groups to be compared have the same population median.

The extent to which the peak of a unimodal probability distribution or frequency distribution departs from the shape of a normal distribution by either being more pointed (leptokurtic) or flatter (platykurtic). For a normal distribution, the value of kurtosis is zero (mesokurtic).

An approach to comparing a set of means that controls the familywise error rate at some particular level, say α. The hypothesis of the equality of the means is tested first by an α-level F test . If this test is not significant, then the procedure terminates without making detailed inferences on pairwise differences; otherwise, each pairwise difference is tested by an α-level Student's t test.

A method used to estimate parameters, particularly in regression analysis, by minimizing the difference between the observed response and the value predicted by the model. Often referred to as “ordinary least squares” to differentiate this simple version of the technique from more involved versions, such as weighted least squares and iteratively weighted least squares.

A procedure for the detection of outliers that uses the difference between the log likelihood of the complete data set and the log likelihood when a particular observation is removed. If the difference is large, then the observation involved is considered an outlier.

A function constructed from a statistical model and a set of observed data that gives the probability of the observed data for various values of the unknown model parameters. The parameter values that maximize the probability are the maximum likelihood estimates of the parameters.

The ratio of the likelihoods of the data under two hypotheses, H 0 and H 1. May be used to assess H 0 against H 1.

An ordinal scale of responses to a question or statement ordered in a hierarchical sequence, such as from “strongly agree” through “no opinion” to “strongly disagree.”

A function of a set of variables, parameters, etc., that does not contain powers or cross-products quantities.

A statistical model in which the expected value of a parameter for a given value of a factor, x , which is assumed to be equal to a + bx, where a and b are constants.

Regression analysis of data using linear models.

A relationship between two variables in which the values of one variable change at a constant rate as the value of the other variable increases.

A method used to test the hypothesis that a genetic marker of known location is on a chromosome different from that on which a gene postulated to govern susceptibility to a disease is located.

A term often used in epidemiology for the logarithm of an odds ratio. Also used in genetics for the logarithm of a likelihood ratio.

The transformation of a variable, x , obtained by taking y = log( x ). Often used when the frequency distribution of the variable, x , shows a moderate to large degree of skewness to achieve normality.

A form of regression analysis used when the response variable is a binary variable.

The logarithm of the ratio of frequencies of two different categorical outcomes, such as healthy versus sick.

The upper and lower ends of the confidence interval for the logarithm of the odds ratio.

A statistical model that uses an analysis of variance type of approach for the modeling of frequency counts in contingency tables.

The probability distribution of a variable, x, for which log ( x − a ) has a normal distribution with mean m and variance σ 2 .

A method for comparing the survival times of two or more groups of subjects that involves the calculation of observed and expected frequencies of failures in separate time intervals.

A concept used in decision analysis that assigns numerical values to making good or poor decisions.

The process applied to the results from bioassays for carcinogenicity conducted with animals at doses that are generally well above human exposure levels to assess risk in humans.

An estimate of the independent effect of (usually) a factor variable on a response variable in an analysis of variance.

A test that compares two groups of ordinal scores and that shows the probability that they form parts of the same distribution. It is a nonparametric equivalent of the t test.

An estimate of the assumed common odds ratio in a series of two-by-two contingency tables arising from different populations, e.g., occupation or country of origin.

A calculated test statistic that uses a standard normal deviate rather than a chi-square value. The test, used to control for confounding, examines the null hypothesis that the variables are independent by looking at just one of the four cells.

A regression test of the odds ratio against a numerical variable representing ordered categories of exposure. It may be used to analyze the results of a case-control study.

A stochastic process such that the conditional probability distribution for the state at any future instant, given the present state, is unaffected by any additional knowledge of the past history of the system. See also random walk.

Procedure intended to keep a participant(s) in a study from knowing some fact(s) or observation(s) that might bias or influence that participant's actions or decisions regarding the study. See also blinding.

The process of making a study group and a comparison group comparable with respect to extraneous factors. Often used when selecting cases and controls in retrospective studies to control variation in a response variable due to sources other than those immediately under investigation.

The value for an unknown parameter that maximizes the probability of obtaining exactly the data that were observed.

The highest possible dose of a drug that can be given with acceptable toxicity to the patient. This dose is usually determined in a phase I clinical trial and is the dose recommended for use in future studies.

A form of the chi-square test for matched-pairs data. It is a special case of the Mantel-Haenszel test .

The expected value of the square of the difference between an estimator and the true value of a parameter. If the estimator is unbiased, then the mean squared error is simply the variance of the estimator. For a biased estimator the mean squared error is equal to the sum of the variance and the square of the bias.

The ratio of two mean squares in analysis of variance.

The name used in the context of analysis of variance for estimators of particular variances of interest. For example, in the analysis of a one-way design, the within-groups mean square estimates the assumed common variance in k groups.

Systematic error arising from inaccurate measurements (or classification) of a study variable(s) for subjects.

Errors in reading, calculating, or recording a numerical value. The difference between the observed values of a variable recorded under similar conditions and some fixed true value.

The range of possible values for a measurement, e.g. the set of possible responses to a question.

Numerical indices quantifying the strength of the statistical dependence of two or more qualitative variables.

A measure of central tendency. It is the value in a set of ranked observations that divides the data into two parts of equal size. When there is an odd number of observations, the median is the middle value. When there is an even number of observations, the median is calculated as the average of the two central values.

The process of using statistical methods to combine the results of two or more independent studies to yield an overall answer to a question of interest. The rationale behind this approach is to provide a test with more power than that provided by the separate studies themselves.

A method for allocation of patients to treatments in clinical trials that is usually an acceptable alternative to random allocation. The procedure ensures balance between the groups to be compared on prognostic variables, by allocating with a high degree of probability the next patient to enter the trial to whatever treatment would minimize the overall imbalance between the groups on the prognostic variables, at that stage of the trial.

A method of estimation that finds estimates of the parameters of some model of interest by minimizing the chi-squared statistic for the assessment of differences between the observed values and those predicted by the model.

Observations missing from a set of data. These occur for a variety of reasons, e.g., subjects drop out of the study, subjects do not appear for one or other of the scheduled visits, or there is an equipment failure. Otherwise known as “missing completely at random.”

A model usually encountered in the analysis of longitudinal data in which some of the parameters are considered to have fixed effects and some are considered to have random effects. For example, in a clinical trial with two treatment groups in which the response variable is recorded for each subject at a number of visits, the treatments would usually be regarded as having fixed effects and the subjects would usually be regarded as having random efffects.

One of the measures of central tendency. It is the most frequently occurring value in a set of observations.

Method for finding solutions to mathematical and statistical problems by simulation.

A clinical trial conducted simultaneously in a number of participating hospitals or clinics, with all centers following a universal study protocol and with independent random allocation within each center.

In multiple regression analysis, a situation in which at least some of the independent variables are highly correlated directly or indirectly with each other. Such a situation can result in inaccurate estimates of the parameters in the regression model.

Method of analysis that explains individual outcomes in terms of both individual and environmental or aggregate variables.

A probability distribution or frequency distribution with several modes. Multimodality is often taken as an indication that the observed distribution results from the mixing of the distributions of relatively distinct groups of observations.

The probability distribution associated with the classification of each of a sample of individuals into one of several mutually exclusive and exhaustive categories. When the number of categories is two, the distribution is called binomial.

Procedures for detailed simultaneous examination of the differences between a set of means, usually after a general hypothesis that they are all equal has been rejected. Examples are Bonferroni correction , Duncan's multiple-range test, Dunnett's test, and Tukey's method. No single technique is best in all situations, and a major distinction between techniques is how they control the possible inflation of the Type I error .

The correlation between the observed values of the dependent variable in a multiple regression and the values predicted by the estimated regression equation. Often used as an indicator of how useful the explanatory variables are in predicting the response.

A term used to describe the variety of outcome measures used in many clinical trials. There are a number of ways to measure treatment success, e.g, length of patient survival, percentage of patients experiencing tumor regression, or percentage of patients surviving for 2 years. The aim in using a variety of such measures is to gain better knowledge of the differences between the treatments being compared.

A statistical model in which a continuous response variable, y, is regressed on a number of explanatory variables, X 1 , X 2 , . . ., X q . The model is E ( y ) = β 0 + β 1 X 1 + . . . + β q X q where E denotes the expected value. The parameters in the model, the regression coefficients β 0 , β 1 , β q , are generally estimated by least squares estimation. Each coefficient gives the change in the response variable corresponding to a unit change in the appropriate explanatory variable, conditional on the other variables remaining constant.

For events A and B that are independent, the probability that both occur is the product of the separate probabilities, i.e., P ( A and B ) = P ( A ) P ( B ), where P denotes probability.

A model in which the combined effect of a number of factors, when applied together, is the product of their separate effects.

An analytical method that allows the simultaneous study of two or more dependent variables.

A procedure for testing the equality of the mean vectors of more than two populations. The technique is analogous to the analysis of variance of univariate data, except that the groups are compared on q response variables simultaneously. In the univariate case, F tests are used to assess the hypotheses of interest. In the multivariate case, no single test statistic that is optimal in all situations can be constructed.

Data for which each observation consists of values for more than one random variable, e.g., measurements of blood pressure, temperature, and heart rate for a number of subjects.

The simultaneous probability distribution of a set of random variables.

A method for assessing the effect of explanatory variables on a set of two or more correlated binary response variables.

The probability that a person having a negative result or a diagnostic test does not have the disease.

A multiple-comparison test used to investigate in more detail the differences existing between a set of means, as indicated by a significant F test in an analysis of variance.

A variation of a randomized controlled trial in which a sequence of alternative treatment regimens is randomly allocated to a single patient. The outcomes of successive regimens are compared, with the aim being determination of the optimum regimen for the patient.

A variable that gives the appropriate label of an observation after allocation to one of several possible categories, for example, gender (male or female), marital status (married, single, or divorced), or blood group (A, B, AB, or O).

A line chart showing scales for the variables involved in a particular formula in such a way that corresponding values for each variable lie on a straight line that intersects all the scales.

A trial in which a series of consecutive patients receive a new treatment and those who respond (according to some predefined criterion) continue to receive it. Patients who fail to respond receive an alternative treatment. The two groups are then compared on one or more outcome variables.

A term used for failure to provide the relevant information being collected in a survey for a variety of reasons. A large number of nonrespondents may introduce bias into the final results.

The dose level of a compound below which there is no evidence of an effect on the response of interest.

A normal distribution with mean np and variance np (1 − p ) that acts as an approximation to a binomial distribution as n , the number of trials, increases. The term p represents the probability of a “success” of any trial.

A probability distribution of a random variable, x , that is assumed by many statistical methods. The properties of a normal distribution are as follows: (1) it is a continuous, symmetrical distribution; both tails extend to infinity; (2) the arithmetic mean, mode, and median are identical; and (3) its shape is determined by the mean and standard deviation. Synonym for Gaussian distribution .

The probability distribution of a test statistic when the null hypothesis is true.

The statistical hypothesis that one variable has no association with another variable or set of variables or that two or more population distributions do not differ from one another.

In clinical treatment regimens, the number of patients with a specified condition who must follow the specified regimen for a prescribed period to prevent the occurrence of a specified complication(s) or an adverse outcome(s) of the condition.

Tests that assess the differences between treatment groups and that take account of the possible heterogeneous nature of the response treatment. They may lead to the identification of subgroups of patients for whom the experimental therapy might have the most or the least benefit.

The ratio of the probability of the occurrence of an event to that of the nonoccurrence of the event.

The ratio of the odds for a binary variable in two groups of subjects. For example, if the two possible states of the variable are labeled “success” and “failure,” then the odds ratio is a measure of the odds of a success in one group relative to that in the other.

A form of matching often used when control subjects are more readily obtained than cases. A number, m (m > 1), of controls are attached to each case, with these being known as the matched set. The theoretical efficiency of such matching in estimating, e.g., relative risk, is m/(m+1), so one control per case is 50 percent efficient, whereas four controls per case is 80 percent efficient. Increasing the number of controls beyond 5 to 10 brings rapidly diminishing returns.

A statistical significance test based on the assumption that the data have only one possible direction of variability. The choice between a one-sided test and a two-sided test must be made before any test statistic is calculated.

See analysis of variance.

A measurement that allows a sample of individuals to be ranked with respect to some characteristic but for which differences at different points of the scale are not necessarily equivalent. For example, anxiety might be rated on a scale of “none,” “ mild, ” “moderate,” and “severe,” with the values 0, 1, 2, and 3 respectively, being used to label the categories.

All the possible results that may stem from exposure to a causal factor or from preventive or therapeutic interventions; all identified changes in health status arising as a consequence of the handling of a health problem.

Observations that differ so widely from the rest of the data as to lead one to suspect that a gross error may have been committed in measurement or recording.

A situation that may arise when the matching procedure partially or completely obscures evidence of a true causal association between the independent and dependent variables. The matching variable may be an intermediate cause in the causal chain, or it may be strongly affected by or a consequence of such an intermediate cause.

A design that can reduce selection bias in situations in which it is not possible to use random allocation of subjects to treatments. In the experimental groups, the new treatment is made available to all subjects, although some may not receive it. In the control groups, the experimental treatment is generally not available to subjects, although some subjects may receive it in special circumstances.

In a clinical trial, two samples of observations with the characteristic feature that each observation in one sample has one and only one matching observation in the other sample. One member of each pair receives the experimental regimen, and the other member of each pair receives a suitably designated control regimen.

A simple experimental setup in which two different groups of patients, e.g., treated and untreated patients, are studied concurrently.

One of the assumptions made in the analysis of covariance, namely, that the slope of the regression line relating the response variable to the covariate is the same in all treatment groups.

A hypothesis concerning the parameter(s) of a distribution, e.g., the hypothesis that the mean for a population equals the mean for a second population when the populations are each assumed to have a normal distribution.

Procedures for testing hypotheses about parameters in a population described by a specified distributional form, often a normal distribution. Student's t test is an example of such a method.

The correlation between a pair of variables after adjusting for the effect of a third variable.

An index for examining the linear relationship between a response variable and a group of explanatory variables while controlling for another group of variables.

A mode of analysis involving assumptions about the direction of causal relationships between linked sequences and configurations of variables. This allows the analyst to construct and test the appropriateness of alternative models (in the form of a path diagram) of the causal relations that may exist within the array of variables.

See correlation coefficient.

A measurement combining persons and time, used as denominator in person-time incidence and mortality rates. It is the sum of individual units of time that the persons in the study population have been exposed to the conditions of interest. The most frequently used person-time is person-years.

See person-time.

A phenomenon in which patients given only inert substances often show subsequent clinical improvement compared with patients who received the actual treatment.

A term for those patients in a clinical trial who report side effects normally associated with the active treatment while receiving a placebo.

A procedure in clinical trials in which the response to treatment is either positive (a success) or negative (a failure). One of the two treatments is selected at random and used on the first patient; thereafter, the same treatment is used on the next patient whenever the response of the previously treated patient is positive and the other treatment is used whenever the response is negative.

See estimate.

A distribution function used to describe the occurrence of rare events or to describe the sampling distribution of isolated counts in a continuum of time or space. This distribution is used to model person-time incidence rates.

A linear model in which powers and possibly cross-products of explanatory variables are included, e.g., y = β 0 + β 1 x + β 2 x 2 .

The probability that a person having a positive result on a diagnostic test actually has a particular disease.

The probability of rejecting the null hypothesis when it is false. Power gives a method of discriminating between competing tests of the same hypothesis, with the test with the higher power being preferred. It is also the basis of procedures for estimating the sample size needed to detect an effect of a particular magnitude.

A term applied to the likely spread of estimates of a parameter in a statistical model. Measured by the standard error of the estimator, which can be decreased, and hence precision is increased, by using a larger sample size.

The variables that appear on the right side of the equation defining, e.g., multiple regression or logistic regression, and that aim to predict or explain the response variable.

Probability distribution that summarizes information about a random variable or parameter known or assumed at a given time point before further information about empirical data is obtained. It is used in the context of Bayesian inference .

For a discrete random variable, a mathematical formula that gives the probability of each value of the variable. Examples are binomial distribution and Poisson distribution . For a continuous random variable, a curve described by a mathematical formula that specifies, by way of areas under the curve, the probability that the variable falls within a particular interval. Examples are normal distribution and exponential distribution.

A sample obtained by a method in which every individual in a finite population has a known, but not necessarily equal, chance of being included in the sample.

The probability of the observed data (or data showing a more extreme departure from the null hypothesis) when the null hypothesis is true.

A technique most commonly used in bioassays, particularly toxilogical experiments in which sets of animals are subject to known levels of a toxin, and a model is required to relate the proportions surviving at a particular dose to the dose. In this type of analysis the probit transformation of a proportion is modeled as a linear function of the dose or, more commonly, the logarithm of the dose. Estimates of the parameters in the models are found by maximum likelihood estimation.

A transformation used in the analysis of dose-response curve.

See Cox's proportional hazards model .

A model for investigating the dependence of an ordinal variable on a set of explanatory variables. In the most commonly used version of the model, the cumulative probabilities, P ( y ≤ k ), where y is the response variable with categories 1 ≤ 2 ≤ 3 ... ≤ c , are modeled as linear functions of the explanatory variables via the logistic transformation. The name proportional odds arises since the odds ratio of having a score of k or less for two different sets of values of the explanatory variables does not depend on k.

The proportion of cases of disease prevented by the vaccine, usually estimated as PE = (ARU − ARV)/ ARU, where ARV and ARU are the attack rates of the disease under study among the vaccinated and unvaccinated cohorts, respectively. For example, if the rate of disease is 100 per 10,000 in an unvaccinated group but only 30 per 10,000 in a comparable vaccinated group, the PE is 70 percent.

A formal document outlining the proposed procedures for carrying out a clinical trial. The main features of the document are study objectives, patient selection criteria, treatment schedules, methods of patient evaluation, trial design, procedures for dealing with protocol violations, and plans for statistical analysis.

Deliberate or accidental failure of patients to follow one or other aspects of a protocol for a clinical trial. For example, the patients may not have taken their prescribed medication. Such patients are said to show noncompliance.

A sampling procedure used with spatial data in which sample areas (the quadrants) are taken and the number of objects or events of interest occurring in each is recorded.

Divisions of a probability distribution or frequency distribution into equal, ordered subgroups, e.g., quartiles or percentiles.

A three-parameter nonlinear logistic regression model.

The values that divide a frequency distribution or probability distribution into four equal parts.

A function that is used as the basis for the estimation of parameters when it is not possible (or desirable) to make a particular distributional assumption about the observations, with the consequence that it is not possible to write down their likelihood. The function depends on the assumed relationship between the mean and the variance of the observations.

The set of four variate values that divide a frequency distribution or a probability distribution into five equal parts.

A sample in which the units are not selected completely at random, but are selected in terms of a certain number of units in each of a number of categories, e.g., 10 men over age 40 or 25 women between ages 30 and 35.

A diagram used to display the odds ratios calculated from a number of different clinical trials of the same treatment(s). The diagram consists of a plot of y = Δ ̂ / SE ( Δ ̂ ) against x = 1/ SE ( Δ ̂ ), where Δ ̂ is the logarithm of the odds ratio from a particular study and SE is standard error. Often useful in meta-analysis.

Allocation of individuals to groups, e.g., for experimental and control regimens, by chance. It follows a predetermined plan that is usually devised with the aid of a table of random numbers. The control and experimental groups should be similar at the start of the investigation, and the investigator's personal judgment and prejudices should not influence allocation.

The effects attributable to an infinite set of levels of a factor, only a randomsample of which occurs in the data.

Procedures for determining statistical significance directly from data, without recourse to some particular sampling distribution. The data are divided repeatedly between treatments, and for each division the relevant test statistic e.g., t or F is calculated to determine the proportion of the data permutations that provide as large a test statistic as that associated with the observed data. If that proportion is smaller than some significance level ?, the results are significant at the ? level.

A clinical trial that involves the formation of treatment groups by the process of random allocation.

A design originally introduced to overcome some of the perceived ethical problems facing clinicians entering patients in randomized clinical trials. After the patient's eligibility is established, the patient is randomized to one of two treatments, treatments A and B. The risks, benefits, and treatment options are discussed with patients randomized to receive treatment A, and the patients are asked if they are willing to receive the therapy. Those who do not agree receive treatment B or some alternative treatment. The same procedure is followed for patients who were randomized to receive treatment B.

Either a set of n independent and identically distributed random variables or a sample of n individuals selected from a population in such a way that each sample of the same size is equally likely.

A variable, the values of which occur according to some specified probability distribution.

The variation in a data set unexplained by identifiable sources.

The path traversed by a particle that moves in steps, with each step being determined by chance in regard to direction or magnitude, or both. Random walk may be applied to sequential sampling.

The difference between the largest and the smallest observations in a data set.

The range of differences between two treatments being compared in a clinical trial within which it is not possible to make a definite choice of treatment.

Correlation coefficients that depend only on the ranks of the variables, not on their observed values. Examples are Kendall's tau statistics and Spearman's rho correlation coefficient.

Statistics based only on the rank of the sample observations, e.g., Kendall's tau statistics.

The value obtained by dividing one quantity by another: a general term of which rate, proportion, percentage, etc., are subsets. It is an expression of the relationship between a numerator and a denominator in which the two are usually separate and distinct quantities, with neither being included in the other.

A plot of the sensitivity ( y axis) of a diagnostic test against the complement of its specificity ( x axis) that ascertains the balance between specificity and sensitivity corresponding to various cutoffs.

A general term for methods of analysis that are concerned with estimating the parameters in some postulated relationship between a response variable and one or more explanatory variables. Examples are linear regression, logistic regression, and multiple regression.

See multiple regression.

Procedures designed to investigate the assumptions underlying a regression analysis (e.g., normality or homogeneity of variance) or to examine the influence of particular datum points or small groups of datum points on the estimated regression coefficients.

Diagrammatic presentation of a regression equation, usually drawn with the independent variable, x , as the abscissa and the dependent variable, y , as ordinate.

The ratio of the observed survival for a given group of patients to the survival that group would have experienced on the basis of the life table for the population for which the diagnosis was made.

The degree to which the results obtained by a measurement procedure can be replicated.

The closeness of results obtained on the same test material under changes of reagents, conditions, techniques, apparatus, laboratories, and so on.

The difference between the observed value of a response variable ( yi ) and the value predicted by some model of interest ( yi ). Examination of a set of residuals, usually by informal graphical techniques, allows the assumptions made in the model-fitting exercise (e.g., normality and homogeneity of variance) to be checked.

Potential confounding by factors or variables not yet considered in the analysis, which may be directly observable or not.

The systematic component of the difference between information provided by survey respondent and the “truth.”

The number of completed or returned survey instruments (questionnaires, interviews, etc.) divided by the total number of persons who would have been surveyed.

The variable of primary importance in medical investigations, since the major objective is usually to study the effects of a treatment or other explanatory variables on this variable.

A method of estimation in which estimators of parameters are derived by maximizing the restricted likelihood rather than the likelihood itself.

The estimate of the proportion of subjects misclassified by a rule derived from a discriminant analysis, obtained by reclassifying the training set by using the rule.

A method of regression analysis designed to overcome the possible problem of multicollinearity among the explanatory variables. Such multicollinearity makes it difficult to estimate the separate effects of variables on the response. This form of regression may result in increased precision.

A method of analysis for ordinal variables that proceeds from the assumption that the ordered categorical scale is an approximation to an underlying, but not directly measurable, continuous variable. Numerical values called ridits are calculated for each category. These values are estimates of the probability that a subject's value on the underlying variable is less than or equal to the midpoint of the corresponding interval.

The qualitative or quantitative estimation of the likelihood of adverse effects that may result from exposure to specified health hazards or from the absence of beneficial influences.

Methods of estimation that work well not only under ideal conditions but also under conditions representing a departure from an assumed distribution or model.

A general class of statistical procedures designed to reduce the sensitivity of the parameter estimates to failures in the assumption of the model. For example, least squares estimation is known to be sensitive to outliers, but the impact of such observations can be reduced by basing the estimation process not on a sum-of-squares criterion but on a sum-of-absolute values criterion.

Statistical procedures and tests that work well even when the assumptions on which they are based are moderately violated. An example is Student's t test.

A method based on the Poisson distribution which states that if in n trials zero events of interest are observed, a 95 percent confidence (with limits of 0 and 3) bound on the underlying rate is 3/ n.

A period of observation before the formation of treatment groups by random allocation, during which subjects acquire experience with the major components of a study protocol. Those subjects who experience difficulty complying with the protocol are excluded, whereas the group of proven compliers is randomized into the trial.

In a series of observations, the occurrence of an uninterrupted sequence of the same value. For example, in the series 1111222433333 there are four “runs”, with the single value, 4, being regarded as a run of length unity.

A test frequently used to detect serial correlations. The test consists of counting the number of runs or sequences of positive and negative residuals and comparing the result with the expected value under the null hypothesis of independence.

The process of deciding, before a study begins, how many subjects should be studied. It takes into account the incidence or prevalence of the condition being studied, the estimated or putative relationship among the variables in the study, the power that is desired, and the allowable Type I error .

The difference between the sample result and the population characteristic being estimated. In practice, the sampling error can rarely be determined because the population characteristic is not usually known. With appropriate sampling procedures, it can be kept small and the investigator can determine its probable limits of magnitude.

The variation shown by different samples of the same size from the same population.

Zero frequencies that occur in the cells of contingency tables because of inadequate sample size.

A model that contains all main effects and all possible interactions between factors. Such a model contains the same number of parameters as observations and results in a perfect fit for a data set.

A graphic method of displaying the distribution of two variables in relation to each other.

The bias that may be introduced into clinical trials and other types of medical investigations whenever a treatment is chosen by the individual involved or is subject to constraints that go unobserved by the researcher.

Half the difference between the upper and lower quartiles.

An index of the performance of a diagnostic test, calculated as the percentage of individuals with a disease who are correctly classified as having the disease, i.e., the conditional probability of having a positive test result given that the disease is present.

Administration of antigen to induce a primary immune response.

A method of analysis in which a statistical test of significance is conducted repeatedly over time as the data are collected. After each observation, the cumulative data are analyzed and one of the following three decisions is taken: stop the data collection, reject the null hypothesis, and claim statistical significance; stop the data collection, do not reject the null hypothesis, and state that the results are not statistically significant; continue the data collection since the accumulated data are inadequate to draw a conclusion. Three types of sequential analysis are: open-ended sequential analysis, used in studies that continue indefinitely until sufficient evidence to reject or fail to reject the null hypothesis has accumulated; closed-ended sequential analysis, in which the maximum size of the sample has been set and as data are accumulated and analyzed there is an option to terminate the study before data from the planned sample size have accumulated; and group sequential analysis, in which interim analysis is undertaken at planned numbers of intervals, with each interval having accumulated data for a specified number of samples.

A term in regression analysis that refers to the contribution of variables as they are added to the model in a particular sequence. It is the difference in the residual sum of squares before and after adding a variable.

A hereditary, genetically determined hemolytic anemia, one of the hemoglobinopathies, occurring almost exclusively in African Americans, characterized by arthralgia, acute attacks of abdominal pain, ulcerations of the lower extremities, and sickle-shaped erythrocytes in the blood.

The level of probability at which it is agreed that the null hypothesis will be rejected, conventionally set at 0.05.

A statistical procedure that, when applied to a set of observations, results in a p value relative to some hypothesis. Examples include Student's t test, z test, and Wilcoxon's signed rank test .

A test that can be used when combining results of several studies, e.g., in meta-analysis. The test considers the direction of results of individual studies, whether the associations demonstrated are positive or negative.

Coefficients that range from zero to unity and that are used to measure the similarity of the variable values of two observations from a set of multivariate data. Most commonly used on binary variables.

A form of confounding in which the presence of a confounding variable changes the direction of an association. It may occur in meta-analysis because the sum of the data or results from a number of different studies may be affected by confounding variables that have been excluded by design features from some studies but not others.

Censored observations that occur in clinical trials in which all the patients enter the study at the same time point and in which the study is terminated after a fixed time period.

The lack of symmetry in a probability distribution.

A collection of measurements or observations on one or more variables taken at specified locations and for which the spatial organization of the data is of primary interest.

An index of the performance of a diagnostic test, calculated as the percentage of individuals without the disease who are classified as not having the disease, i.e., the conditional probability of a negative test result given that the disease is absent.

The most commonly used measure of the spread of a set of observations. Equal to the square root of the variance.

A set of techniques used to remove as much as possible the effects of differences in age or other confounding variables when comparing two or more populations. The common method uses weighted averaging of rates specific for age, sex, or some potential confounding variable(s) according to some specified distribution of these variables.

A normal distribution with zero mean and unit variance.

A random variable having a standard normal distribution.

Variable values transformed to zero mean and unit variance.

A numerical characteristic of a sample, e.g., sample mean and sample variance.

An estimate of the probability of the observed or greater degree of association between independent and dependent variables under the null hypothesis. The level of statistical significance is usually stated by the p value.

A procedure that is intended to decide whether a hypothesis about the distribution of one or more populations or variables should be rejected or accepted.

A method of displaying data resembling a histogram in which each observation is split into two parts, with multiples of 10 along the “stem” and the integers forming the “leaves.” The stems are arranged in a column, and the leaves are attached to the relevant stem.

A process that incorporates some element of randomness, in a series of random variables, xt, where t assumes values in a certain range T . In most cases xt is an observation at time t and T is a time range.

Procedures that allow interim or sequential analyses in clinical trials at predefined times and that specify the conditions or criteria under which the trial shall be terminated while preserving the Type I error at some prespecified level.

A method for comparing the survival experiences of two groups of subjects given different treatments when the groups are stratified by age or some other prognostic variable.

A randomization procedure in clinical trials in which strata are identified and subjects are randomly allocated to treatments within each stratum without sacrificing the advantages of random allocation.

Zero frequencies occurring in the cells of contingency tables that arise because it is theoretically impossible for an observation to fall in the cell.

The probability distribution of the ratio of a standard normal variable to the square root of a variable with a chi-square distribution. The shape of the distribution varies with n, and as n gets larger the shape of the t distribution approaches that of the standard normal distribution.

Significance tests for assessing hypotheses about population means. One version, known as single-sample t test, is used in situations in which it is required to test whether the mean for a population takes a particular value. Another version, known as independent-samples t test, is applied when independent samples are available from each population and is designed to test the equality of the means for the two populations.

The analysis of particular subgroups of patients in a clinical trial to assess possible treatment-subgroup interactions. Analysis of many subgroups for treatment effects can increase overall Type I error rates.

End points in clinical trials that can be measured only by subjective clinical rating scales.

In clinical trials it refers to an outcome measure that an investigator considers to be highly correlated with an endpoint of interest but that can be measured at lower expense or at an earlier time. In some cases, ethical issues may suggest the use of a surrogate endpoint.

The probability that the survival time of an individual is longer than some particular value. A plot of this probability against time is called a survival curve and is a useful component in the analysis of such data.

A probability distribution or frequency distribution that is symmetrical about some central value.

Procedures for allocating treatments to patients in a clinical trial that attempts to emulate random allocation by using some systematic scheme, such as giving treatment A to those people with birth dates on even dates and treatment B to those with birth dates on odd days.

A term often used in a clinical laboratory to describe the difference in results caused by a bias of an assay.

The collection of individuals, items, measurements, etc., about which it is required to make inferences. At times it is used to indicate the population from which a sample is drawn, and at times it is used to denote any reference population about which inferences are required.

The distribution of a quotient of independent random variables, the numerator of which is a standardized normal variate and the denominator of which is the positive square root of the quotient of a chi-square-distributed variate and its number of degrees of freedom.

A statistic used to assess a particular hypothesis in relation to some population. The essential requirement of such a statistic is a known distribution when the null hypothesis is true.

A term usually applied to ordinal variables to indicate observations that take the same value on a variable.

Covariates whose values change over time. Examples are age and weight.

Covariates whose values remain constant over time. An example is a pretreatment measurement of some characteristic.

A measure traditionally used to compare treatments in bioequivalence trials. It is the time at which a patient's highest recorded values occur.

The sum of the squared deviations of all the observations from their mean.

A simple rule for approximating the integral of a function, f ( x ), between two limits.

The ratio of the number of subjects allocated to the two treatments in a clinical trail. Equal allocation is most common in practice, but it may be advisable to allocate patients randomly in other ratios when a new treatment is compared with an old one, or when one treatment is much more difficult or expensive to administer.

An instance in which a patient assigned to receive a particular treatment in a clinical trial is exposed to one of the other treatments during the course of the trial.

Analyzing the results of a clinical trial by the treatment received by a patient rather than by the treatment allocated at randomization as in intent-to-treat analysis.

Synonym for clinical trial.

Movement in one direction of the values of a variable over a period of time.

A study in which the subjects, observers, and analysts are blinded as to which subjects received what interventions.

Data for which sample values larger (truncated on the right) or smaller (truncated on the left) than a fixed value are either not recorded or not observed.

Test that uses a statistic that, under the null hypothesis, has the t distribution to test whether two means differ significantly or to test linear regression or correlation coefficients.

The daily dose of a compound required to halve the probability of remaining tumorless at the end of a standardized lifetime.

An allocation procedure for forming treatment groups in a clinical trial in which the probability of assigning a patient to a particular treatment is a function of the observed differences in outcomes for patients already enrolled in the trial.

A contingency table with two rows and two columns formed from cross classification of two binary variables.

A sampling scheme involving two distinct phases: first, information about particular variables of interest is collected for all members of the sample, and second, information about other variables is collected for a subsample of the individuals in the original sample.

A procedure most often used in the assessment of quality assurance before, during, and after the manufacture of, e.g., a drug product. This would involve randomly sampling a number of packages of some drug and then sampling a number of tablets from each of these packages.

A procedure sometimes used in clinical trials in which results are first examined after only a fraction of the planned number of subjects in each group have completed the trial. The relevant test statistic is calculated and the trial is stopped if the difference between the treatments is significant at stage 1 level. Otherwise, additional subjects in each treatment group are recruited, the test statistic is calculated again, and the groups are compared at stage 2 level α 2 , where α and α 2 are chosen to give an overall significance level of α.

A statistical significance test based on the assumption that the data are distributed in both directions from some central value(s).

The error that results when the null hypothesis is falsely rejected.

The error that results when the null hypothesis is falsely accepted.

A requirement that all of a number of diagnostic tests yield positive results before declaring that a patient has a particular complaint.

An estimator that for all sample sizes has an expected value equal to the parameter being estimated. If an estimator tends to be unbiased as the sample size increases, it is referred to as “asymptotically unbiased.”

The probability distribution of a random variable having constant probability over an interval. The most commonly encountered uniform distribution is one in which the parameters α and β take the values 0 and 1, respectively.

A probability distribution or frequency distribution having only a single mode.

Synonym for standard normal variable.

Data involving a single measurement for each subject or patient.

An approach to the analysis of two-way and higher-order factorial designs when there are an unequal number of observations in each cell. The analysis is based on cell means, using the harmonic mean of all cell frequencies as the sample size for all cells.

A probability distribution or frequency distribution shaped more or less like a letter U, although not necessarily symmetrical. The distribution has its greatest frequencies at the two extremes of the range of the variable.

In economics, utility means preference for or desirability of a particular outcome.

A method in clinical decision analysis in which the outcome refers to being or becoming healthy rather than sick or disabled.

A term used for the prior distribution in Bayesian inference in the situation in which there is complete ignorance about the value of a parameter.

The extent to which a measuring instrument is measuring what was intended.

A part of data editing in which one checks that only allowable values or codes are given for the answers to questions asked of subjects.

An expression of the degree to which a measurement measures what it intends to measure.

The degree to which the inference drawn from a study, especially generalizations extending beyond the study sample, are warranted after taking into account the study methods, the representativeness of the study sample, and the nature of the population from which it is drawn.

Any attribute, phenomenon, or event that can have different values from time to time.

A variable that causally precedes the association of the outcome under study.

See confounding.

Independent variable other than the “hypothetical causal variable” that has a potential effect on the dependent variable and that is subject to control by analysis.

A (potentially) confounding variable that has not been brought under control by design or analysis.

A measure of the variation shown by a set of observations, defined by the sum of squares of the deviation from the mean divided by the number of degrees of freedom in the set of observations. In a population, the second moment about the mean.

Variances of random-effect terms in linear models. For example, in a simple mixed model for longitudinal data, both subject effects and error terms are random, and estimation of their variances is of some importance. In the case of a balanced design, estimation of these variances is usually achieved directly from the appropriate analysis of variance table by equating mean squares to their expected values. When the data are unbalanced, a variety of estimation methods might be used, although maximum likelihood estimation and restricted maximum likelihood estimation are most often used.

A symmetric matrix in which the off-diagonal elements are the covariances (sample or population) of pairs of variables and the elements on the main diagonal are the variances (sample or population) of the variables.

An indicator of the effect that the other explanatory variables have on the variance of a regression coefficient of a particular variable, given by the reciprocal of the square of the multiple correlation coefficient of the variable with the remaining variables.

Synonym for F distribution.

Synonym for F test .

Transformation designed so that the variance of the transformed variable is independent of parameters.

A matrix having only one row or column.

A graphical representation of the extent to which two or more quantities or concepts are mutually inclusive and mutually exclusive.

The exposure level to some toxic agent corresponding to an acceptably small risk of suffering an ill effect. From a regulatory perspective, this typically means an increased risk of no more than 10 6 or 10 4 above the background.

A possible source of bias in clinical trials involving volunteers, but not involving random allocation, because of the known propensity of volunteers to respond better to treatment than other patients.

A test for the hypothesis that a vector of parameters, θ' = [θ 1 , θ 2 , . . . , θ m ], is the null vector. The test statistic is, W = θ ̂ 'V − 1 θ ̂ where θ ̂ ' contains the estimated parameter values and V is the asymptotic variance-covariance matrix of θ ̂ . Under the hypothesis, W has an asymptotic chi-square distribution with degrees of freedom equal to the number of parameters.

Dose-response model of the form P ( d ) = 1 − exp(− b d m ), where P ( d ) is the probability of response due to a continuous dose rate d ; and b and m are constants. The model is useful for extrapolating from high- to low-dose exposures, e.g., from animals to human.

A value determined by assigning weights to individual measurements. Each value is assigned a nonnegative coefficient (weight); the sum of the products of each value by its weight divided by the sum of the weights is the weighted average.

A version of the kappa coefficient that allows disagreements between raters to be differentially weighted to allow differences in how serious such disagreements are judged to be.

A method of estimation in which estimates arise from minimizing a weighted sum of squares of the differences between the response variable and its predicted value in terms of the model of interest. Often used when the variance of the response variable is thought to change over the range of values of the explanatory variable(s), in which case the weights are generally taken as the reciprocals of the variance.

Tests designed to ensure that manufacturers control the variation in the weights of the tablet forms of the drugs that they produce.

Another name for the Mann-Whitney test .

A distribution-free method for testing the difference between two populations by using matched samples. The test is based on the absolute differences of the pairs of observations in the two samples ranked according to size, with each rank being given the sign of the original difference.

A test for detecting outliers in multivariate data that assumes that the data arise from a multivariate normal distribution.

A test used to answer questions about the toxicities of substances and at what dose level any toxicity occurs. The test assumes that the mean response of the variate is a monotonic function of dose.

An adjustment proposed by Yates in the chi-square calculation for a two-by-two contingency table that subtracts 0.5 from the positive discrepancies (observed – expected) and adding 0.5 to the negative discrepancies before these values are squared in the calculation of the usual chi-square statistic. This brings the distribution based on the discontinuous frequencies closer to the continuous chi-square distribution from which the published tables for testing chi-square values are derived.

A modified double-blind randomized controlled trial design for the formation of treatment groups in a clinical trial. The essential feature is randomization before informed consent procedures, which is claimed to be needed only for the group allocated to receive the experimental regimen.

A test for assessing hypotheses about population means when their variances are known. If the null hypothesis is true, z has a standard normal distribution.

• Cite this Page Institute of Medicine (US) Committee on Strategies for Small-Number-Participant Clinical Research Trials; Evans CH Jr., Ildstad ST, editors. Small Clinical Trials: Issues and Challenges. Washington (DC): National Academies Press (US); 2001. Appendix B, Glossary of Statistical and Clinical Trials Terms.
• PDF version of this title (1.1M)
• Disable Glossary Links

Recent Activity

• Glossary of Statistical and Clinical Trials Terms - Small Clinical Trials Glossary of Statistical and Clinical Trials Terms - Small Clinical Trials

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

Connect with NLM

National Library of Medicine 8600 Rockville Pike Bethesda, MD 20894

Web Policies FOIA HHS Vulnerability Disclosure

Help Accessibility Careers

Open Educational Resources by Subject Disciplines

• Abnormal Psychology
• Academic Skills
• American Government
• Anatomy and Physiology
• Anthropology
• Art & Art History
• Automotive Services
• Business Communication
• Business Law
• Business Statistics
• Child Care / Early Childhood Development
• Child Psychology
• Climate Change
• Communication
• Comparative Religions
• Computer & Software Application
• Computer Systems Security
• Construction
• Creative Writing
• Criminal Justice
• Culinary Arts
• Cultural Anthropology
• Digital Media Arts
• Earth Science
• English as a Second Language
• Environmental Science
• Exercise Science
• Health, Nursing & Medicine
• Healthcare Career
• Healthcare Terminology/Medical Terminology
• Human Growth and Development
• Interpersonal Communication
• Life Span Psychology
• Managing Operations
• Mathematics
• Microbiology
• Performance Management
• Pharmacology Nursing
• Race and Ethnic Relations
• Radiography
• Statistics and Calculus
• Student Success
• U.S. History
• Understanding Medical Words - Lecture
• Medical Terminology Jukebox
• Medical Terminology Pronunciation
• Medical Terminology for Healthcare Professions New 2021
• Medical Terminology 2nd Edition 2024 From OpenRN

Course Materials

• Medical Terms Tests and Worksheets
• Understanding Medical Words: A Tutorial from the National Library of Medicine
• Quiz one - Des Moines University
• Basic Medical Terminology I Game
• Rules of Medical Terminology - Flashcards - Quizlet
• Medical Terminology From Skills Commons
• Public Health and Healthcare System Terminology From OER Commons
• Word Parts and What they Mean: MedlinePlus
• WebMD: Online Medical Dictionary

Interactive Resources

• Interactive Medical Terminology
• Rules for Medical Terminology
• WebAnatomy University of Minnesota
• Medical Terminology Trivia Game
• Understanding Medical Words

Open Course

• Medical Terminology Course This free online medical terminology course offered by Des Moines University introduces the student learner to approximately 300 medical terms used by health care practitioners in the medical field.
• << Previous: Healthcare Career
• Next: Human Growth and Development >>
• Last Updated: Aug 5, 2024 2:20 PM
• URL: https://libguides.wccnet.edu/oer-subjects

• Find a hospital Results See all results Balashikha 1 hospitals Barnaul 2 hospitals Goryachinsk 1 hospitals Irkutsk 1 hospitals Ivanovo 2 hospitals Kaliningrad 2 hospitals Kazan 2 hospitals Kislovodsk 1 hospitals Korolev 1 hospitals Kovrov 1 hospitals Krasnodar 3 hospitals Krasnogorsk 1 hospitals Moscow 43 hospitals Nizhny Novgorod 3 hospitals Novokuibyshevsk 1 hospitals Novokuznetsk 1 hospitals Novosibirsk 5 hospitals Obninsk 1 hospitals Orenburg 1 hospitals Penza 1 hospitals Saint Petersburg 13 hospitals Samara 3 hospitals Surgut 1 hospitals Tomsk 1 hospitals Tula 1 hospitals Tyumen 1 hospitals Ulan-Ude 1 hospitals Ulyanovsk 2 hospitals Vladivostok 1 hospitals Volgograd 8 hospitals Vologda 1 hospitals Voronezh 1 hospitals Yalta 1 hospitals Yekaterinburg 2 hospitals All hospitals
• Find a sanatorium Results See all results Altai region 4 sanatoriums Buryatia 1 sanatoriums Crimea 4 sanatoriums Ingushetia 1 sanatoriums Karelia 1 sanatoriums Kislovodsk 1 sanatoriums Krasnodar region 2 sanatoriums Moscow region 5 sanatoriums Nizhny Novgorod Region 1 sanatoriums Saint Petersburg region 1 sanatoriums All sanatoriums
• Check the prices Allergology 30 hospitals Andrology 37 hospitals Bariatric surgery 18 hospitals Cardiology 48 hospitals Cosmetology 23 hospitals Dentistry 33 hospitals Dermatology 41 hospitals Dietetics 18 hospitals Endocrinology 47 hospitals Gastroenterology 44 hospitals Genetics 4 hospitals Gynecology 60 hospitals Hematology 21 hospitals IVF (In Vitro Fertilization) 16 hospitals Mammalogy 37 hospitals Maxillofacial Surgery 9 hospitals Narcology 3 hospitals Neurology 58 hospitals Neurosurgery 22 hospitals Obstetrics 15 hospitals Oncology 44 hospitals Ophthalmology 42 hospitals Orthopedics and traumatology 38 hospitals Otolaryngology (ENT) 43 hospitals Pediatrics 31 hospitals Phlebology 36 hospitals Plastic surgery 25 hospitals Proctology 33 hospitals Psychiatry 14 hospitals Pulmonology 28 hospitals Rehabilitation 21 hospitals Rheumatology 29 hospitals Speech therapy 6 hospitals Surgery 41 hospitals Urology 53 hospitals Venereology 25 hospitals
• List of diseases Aesthetic problems 28 hospitals Allergic diseases 32 hospitals Blood diseases 21 hospitals Cardiovascular diseases 50 hospitals Childhood diseases 29 hospitals Colon diseases 33 hospitals Diseases of the digestive system 49 hospitals Diseases of the mammary glands 38 hospitals Diseases of the musculoskeletal system and injuries 45 hospitals Diseases of veins and lymph nodes 39 hospitals Endocrine diseases 51 hospitals ENT (eye, nose, throat) diseases 44 hospitals Eye diseases 45 hospitals Female diseases 62 hospitals Genetic diseases 6 hospitals Infectious diseases 26 hospitals Male diseases 42 hospitals Mental disorders and phenomena 14 hospitals Narcological problems 6 hospitals Nervous diseases 61 hospitals Oncological diseases 46 hospitals Respiratory diseases 30 hospitals Rheumatic diseases 31 hospitals Skin diseases 42 hospitals Speech disorders 7 hospitals Teeth Diseases 34 hospitals Urological diseases 56 hospitals Venereal diseases 28 hospitals
• Our contacts

N.N. Blokhin Russian Cancer Research Center

Tap to book

About hospital

The Blokhin National Medical Research Center of Oncology of the Russian Ministry of Health is the largest oncological clinic in Russia and Europe, one of the largest oncological clinics in the world, which has the latest equipment and all advanced methods of diagnosis and treatment of cancer.

We see our goal as continuous improvement of the quality and availability of cancer care. To achieve this goal, we are working on improving the system of organizing medical care and introducing the latest technologies.

The structure of the center includes five divisions:

• Research Institute of Clinical Oncology named after N.N. Trapeznikov, designed for 900 beds;
• Research Institute of Pediatric Oncology and Hematology, designed for 150 beds;
• Research Institute of Clinical and Experimental Radiology, designed for 50 beds;
• Research Institute of Carcinogenesis, which includes 16 laboratories;
• Research Institute for Experimental Diagnostics and Therapy of Tumors, which includes 15 laboratories.
• The center daily provides high-tech oncological care at the level of the best world standards, using many innovative, including unique technologies to save patients.

On the basis of the center, there are 8 departments of medical academies and universities.

The main activities of the center:

• Provision of highly qualified medical care to patients with malignant neoplasms and precancerous pathology;
• Carrying out scientific research in the field of studying the biology of tumor cells, mechanisms of carcinogenesis and tumor progression (molecular, virological, chemical-physical, genetic, cellular, immunological aspects);
• Experimental and clinical development of new technologies in the field of surgical treatment of malignant tumors;
• Development of new means and methods of diagnostics, drug, radiation and combination therapy, as well as active prevention of tumors;
• Development of issues of diagnosis, treatment and prevention in the field of pediatric oncology;
• Studying the epidemiology of malignant tumors, improving the methods of oncological statistics;
• Development, together with preventive medicine specialists, of a national screening program in oncology;
• Organization and conduct of telemedicine consultations in the following areas: oncology, radiotherapy, radiology, pathological anatomy, cytology, immunology, pediatric oncology, etc .;
• Implementation of the methodological guidance of the oncological service of the Russian Federation, development, together with the professional community and the Ministry of Health of the Russian Federation, of clinical recommendations, procedures and standards for the provision of oncological care;
• The introduction of new devices and technologies in the treatment and diagnostic process and for the prevention of malignant neoplasms;
• Training of scientific and medical personnel through residency, postgraduate studies, doctoral studies and in the system of additional professional education.

Specialization

What diseases are treated, additional services and facilities, booking of online-consultation.

After submitting this form our manager will get in touch with you to inform cost of consultation of selected specialist and agree with you date-time slot for online-talk with doctor.

Submitting Request to N.N. Blokhin Russian Cancer Research Center

For reviewing your case by doctors you need to fill form below.

NEWS... BUT NOT AS YOU KNOW IT

Putin rattled after Moscow ‘under attack from biggest ever drone strike’

Share this with

To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video

Moscow came under one of the largest attacks yet by Ukrainian drones since the start of fighting in 2022, further rattling Vladimir Putin as he attempts to fight Ukrainian troops in the Kursk region.

The Ministry of Defence claimed that Russia downed 45 Ukrainian drones overnight, with 11 destroyed over the Moscow region, 23 over the Bryansk region, six over Belgorod, three over Kaluga and two over Kursk.

Moscow mayor Sergey Sobyanin said on his Telegram channel: ‘This was one of the biggest attempts of all time to attack Moscow using drones.’ 

He said strong defences around the capital made it possible to shoot down all the drones before they could hit their intended targets.

Some Russian social media channels shared videos of drones apparently being destroyed by air defence systems, which then set off car alarms.

Alexander Bogomaz, the governor of the Bryansk region, which borders Ukraine, reported a ‘mass’ attack on his region but that 23 drones were destroyed.

While Ukraine has been bogged down in a land conflict in eastern Europe in which the Russians have been driving forward slowly at a heavy cost to both sides, Kyiv has also been attacking Russia with drones.

Ukraine has targeted oil refineries and airfields in an attempt to weaken Russia’s fighting potential, and has also targeted the capital several times.

The drone attacks come as Ukrainian forces are continuing to push into Russia’s western Kursk region.

The daring incursion into Russia has raised morale in Ukraine with its surprising success and changed the dynamic of the fighting.

But it is uncertain how long Ukraine will be able to hold the territory it has seized in Kursk.

It has also opened up another front in a fight where Ukrainian forces were already badly stretched.

The gains in Kursk come as Ukraine continues to lose ground in its eastern industrial region of Donbas.

The Institute for the Study of War, a think tank based in Washington, said in its daily report late on Tuesday that the Ukrainians had made additional advances in their incursion, now in its third week.

The Russian state news agency Tass reported that 31 people had died since Ukraine’s attack on Russia began on August 6, citing an unnamed source in the medical service – figures which are impossible to verify.

Get in touch with our news team by emailing us at [email protected] .

For more stories like this, check our news page .

MORE : Enzo Maresca and Chelsea can gain relief from off-field disruption with easy win against Servette

MORE : House fire which killed woman and three children was ‘started deliberately’

MORE : TV star ‘appalled’ by Joe Wicks chugging wife’s ‘sweet’ breast milk

Sign Up for News Updates

Get your need-to-know latest news, feel-good stories, analysis and more.

Privacy Policy

Get us in your feed