sources of literature in research study

Literature review sources

Sources for literature review can be divided into three categories as illustrated in table below. In your dissertation you will need to use all three categories of literature review sources:

Sources for literature review and examples

Generally, your literature review should integrate a wide range of sources such as:

• Books . Textbooks remain as the most important source to find models and theories related to the research area. Research the most respected authorities in your selected research area and find the latest editions of books authored by them. For example, in the area of marketing the most notable authors include Philip Kotler, Seth Godin, Malcolm Gladwell, Emanuel Rosen and others.
• Magazines . Industry-specific magazines are usually rich in scholarly articles and they can be effective source to learn about the latest trends and developments in the research area. Reading industry magazines can be the most enjoyable part of the literature review, assuming that your selected research area represents an area of your personal and professional interests, which should be the case anyways.
• Newspapers can be referred to as the main source of up-to-date news about the latest events related to the research area. However, the proportion of the use of newspapers in literature review is recommended to be less compared to alternative sources of secondary data such as books and magazines. This is due to the fact that newspaper articles mainly lack depth of analyses and discussions.
• Online articles . You can find online versions of all of the above sources. However, note that the levels of reliability of online articles can be highly compromised depending on the source due to the high levels of ease with which articles can be published online. Opinions offered in a wide range of online discussion blogs cannot be usually used in literature review. Similarly, dissertation assessors are not keen to appreciate references to a wide range of blogs, unless articles in these blogs are authored by respected authorities in the research area.

Your secondary data sources may comprise certain amount of grey literature as well. The term grey literature refers to type of literature produced by government, academics, business and industry in print and electronic formats, which is not controlled by commercial publishers. It is called ‘grey’ because the status of the information in grey literature is not certain. In other words, any publication that has not been peer reviewed for publication is grey literature.

The necessity to use grey literature arises when there is no enough peer reviewed publications are available for the subject of your study.

John Dudovskiy

• USC Libraries
• Research Guides

Organizing Your Social Sciences Research Paper

• 5. The Literature Review
• Purpose of Guide
• Design Flaws to Avoid
• Independent and Dependent Variables
• Glossary of Research Terms
• Reading Research Effectively
• Narrowing a Topic Idea
• Broadening a Topic Idea
• Extending the Timeliness of a Topic Idea
• Academic Writing Style
• Applying Critical Thinking
• Choosing a Title
• Making an Outline
• Paragraph Development
• Research Process Video Series
• Executive Summary
• The C.A.R.S. Model
• Background Information
• The Research Problem/Question
• Theoretical Framework
• Citation Tracking
• Content Alert Services
• Evaluating Sources
• Primary Sources
• Secondary Sources
• Tiertiary Sources
• Scholarly vs. Popular Publications
• Qualitative Methods
• Quantitative Methods
• Insiderness
• Using Non-Textual Elements
• Limitations of the Study
• Common Grammar Mistakes
• Writing Concisely
• Avoiding Plagiarism
• Footnotes or Endnotes?
• Further Readings
• Generative AI and Writing
• USC Libraries Tutorials and Other Guides
• Bibliography

A literature review surveys prior research published in books, scholarly articles, and any other sources relevant to a particular issue, area of research, or theory, and by so doing, provides a description, summary, and critical evaluation of these works in relation to the research problem being investigated. Literature reviews are designed to provide an overview of sources you have used in researching a particular topic and to demonstrate to your readers how your research fits within existing scholarship about the topic.

Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . Fourth edition. Thousand Oaks, CA: SAGE, 2014.

Importance of a Good Literature Review

A literature review may consist of simply a summary of key sources, but in the social sciences, a literature review usually has an organizational pattern and combines both summary and synthesis, often within specific conceptual categories . A summary is a recap of the important information of the source, but a synthesis is a re-organization, or a reshuffling, of that information in a way that informs how you are planning to investigate a research problem. The analytical features of a literature review might:

• Give a new interpretation of old material or combine new with old interpretations,
• Trace the intellectual progression of the field, including major debates,
• Depending on the situation, evaluate the sources and advise the reader on the most pertinent or relevant research, or
• Usually in the conclusion of a literature review, identify where gaps exist in how a problem has been researched to date.

Given this, the purpose of a literature review is to:

• Place each work in the context of its contribution to understanding the research problem being studied.
• Describe the relationship of each work to the others under consideration.
• Identify new ways to interpret prior research.
• Reveal any gaps that exist in the literature.
• Resolve conflicts amongst seemingly contradictory previous studies.
• Identify areas of prior scholarship to prevent duplication of effort.
• Point the way in fulfilling a need for additional research.
• Locate your own research within the context of existing literature [very important].

Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper. 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Jesson, Jill. Doing Your Literature Review: Traditional and Systematic Techniques . Los Angeles, CA: SAGE, 2011; Knopf, Jeffrey W. "Doing a Literature Review." PS: Political Science and Politics 39 (January 2006): 127-132; Ridley, Diana. The Literature Review: A Step-by-Step Guide for Students . 2nd ed. Los Angeles, CA: SAGE, 2012.

Types of Literature Reviews

It is important to think of knowledge in a given field as consisting of three layers. First, there are the primary studies that researchers conduct and publish. Second are the reviews of those studies that summarize and offer new interpretations built from and often extending beyond the primary studies. Third, there are the perceptions, conclusions, opinion, and interpretations that are shared informally among scholars that become part of the body of epistemological traditions within the field.

In composing a literature review, it is important to note that it is often this third layer of knowledge that is cited as "true" even though it often has only a loose relationship to the primary studies and secondary literature reviews. Given this, while literature reviews are designed to provide an overview and synthesis of pertinent sources you have explored, there are a number of approaches you could adopt depending upon the type of analysis underpinning your study.

Argumentative Review This form examines literature selectively in order to support or refute an argument, deeply embedded assumption, or philosophical problem already established in the literature. The purpose is to develop a body of literature that establishes a contrarian viewpoint. Given the value-laden nature of some social science research [e.g., educational reform; immigration control], argumentative approaches to analyzing the literature can be a legitimate and important form of discourse. However, note that they can also introduce problems of bias when they are used to make summary claims of the sort found in systematic reviews [see below].

Integrative Review Considered a form of research that reviews, critiques, and synthesizes representative literature on a topic in an integrated way such that new frameworks and perspectives on the topic are generated. The body of literature includes all studies that address related or identical hypotheses or research problems. A well-done integrative review meets the same standards as primary research in regard to clarity, rigor, and replication. This is the most common form of review in the social sciences.

Historical Review Few things rest in isolation from historical precedent. Historical literature reviews focus on examining research throughout a period of time, often starting with the first time an issue, concept, theory, phenomena emerged in the literature, then tracing its evolution within the scholarship of a discipline. The purpose is to place research in a historical context to show familiarity with state-of-the-art developments and to identify the likely directions for future research.

Methodological Review A review does not always focus on what someone said [findings], but how they came about saying what they say [method of analysis]. Reviewing methods of analysis provides a framework of understanding at different levels [i.e. those of theory, substantive fields, research approaches, and data collection and analysis techniques], how researchers draw upon a wide variety of knowledge ranging from the conceptual level to practical documents for use in fieldwork in the areas of ontological and epistemological consideration, quantitative and qualitative integration, sampling, interviewing, data collection, and data analysis. This approach helps highlight ethical issues which you should be aware of and consider as you go through your own study.

Systematic Review This form consists of an overview of existing evidence pertinent to a clearly formulated research question, which uses pre-specified and standardized methods to identify and critically appraise relevant research, and to collect, report, and analyze data from the studies that are included in the review. The goal is to deliberately document, critically evaluate, and summarize scientifically all of the research about a clearly defined research problem . Typically it focuses on a very specific empirical question, often posed in a cause-and-effect form, such as "To what extent does A contribute to B?" This type of literature review is primarily applied to examining prior research studies in clinical medicine and allied health fields, but it is increasingly being used in the social sciences.

Theoretical Review The purpose of this form is to examine the corpus of theory that has accumulated in regard to an issue, concept, theory, phenomena. The theoretical literature review helps to establish what theories already exist, the relationships between them, to what degree the existing theories have been investigated, and to develop new hypotheses to be tested. Often this form is used to help establish a lack of appropriate theories or reveal that current theories are inadequate for explaining new or emerging research problems. The unit of analysis can focus on a theoretical concept or a whole theory or framework.

NOTE: Most often the literature review will incorporate some combination of types. For example, a review that examines literature supporting or refuting an argument, assumption, or philosophical problem related to the research problem will also need to include writing supported by sources that establish the history of these arguments in the literature.

Baumeister, Roy F. and Mark R. Leary. "Writing Narrative Literature Reviews."  Review of General Psychology 1 (September 1997): 311-320; Mark R. Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Kennedy, Mary M. "Defining a Literature." Educational Researcher 36 (April 2007): 139-147; Petticrew, Mark and Helen Roberts. Systematic Reviews in the Social Sciences: A Practical Guide . Malden, MA: Blackwell Publishers, 2006; Torracro, Richard. "Writing Integrative Literature Reviews: Guidelines and Examples." Human Resource Development Review 4 (September 2005): 356-367; Rocco, Tonette S. and Maria S. Plakhotnik. "Literature Reviews, Conceptual Frameworks, and Theoretical Frameworks: Terms, Functions, and Distinctions." Human Ressource Development Review 8 (March 2008): 120-130; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016.

Structure and Writing Style

I.  Thinking About Your Literature Review

The structure of a literature review should include the following in support of understanding the research problem :

• An overview of the subject, issue, or theory under consideration, along with the objectives of the literature review,
• Division of works under review into themes or categories [e.g. works that support a particular position, those against, and those offering alternative approaches entirely],
• An explanation of how each work is similar to and how it varies from the others,
• Conclusions as to which pieces are best considered in their argument, are most convincing of their opinions, and make the greatest contribution to the understanding and development of their area of research.

The critical evaluation of each work should consider :

• Provenance -- what are the author's credentials? Are the author's arguments supported by evidence [e.g. primary historical material, case studies, narratives, statistics, recent scientific findings]?
• Methodology -- were the techniques used to identify, gather, and analyze the data appropriate to addressing the research problem? Was the sample size appropriate? Were the results effectively interpreted and reported?
• Objectivity -- is the author's perspective even-handed or prejudicial? Is contrary data considered or is certain pertinent information ignored to prove the author's point?
• Persuasiveness -- which of the author's theses are most convincing or least convincing?
• Validity -- are the author's arguments and conclusions convincing? Does the work ultimately contribute in any significant way to an understanding of the subject?

II.  Development of the Literature Review

Four Basic Stages of Writing 1.  Problem formulation -- which topic or field is being examined and what are its component issues? 2.  Literature search -- finding materials relevant to the subject being explored. 3.  Data evaluation -- determining which literature makes a significant contribution to the understanding of the topic. 4.  Analysis and interpretation -- discussing the findings and conclusions of pertinent literature.

Consider the following issues before writing the literature review: Clarify If your assignment is not specific about what form your literature review should take, seek clarification from your professor by asking these questions: 1.  Roughly how many sources would be appropriate to include? 2.  What types of sources should I review (books, journal articles, websites; scholarly versus popular sources)? 3.  Should I summarize, synthesize, or critique sources by discussing a common theme or issue? 4.  Should I evaluate the sources in any way beyond evaluating how they relate to understanding the research problem? 5.  Should I provide subheadings and other background information, such as definitions and/or a history? Find Models Use the exercise of reviewing the literature to examine how authors in your discipline or area of interest have composed their literature review sections. Read them to get a sense of the types of themes you might want to look for in your own research or to identify ways to organize your final review. The bibliography or reference section of sources you've already read, such as required readings in the course syllabus, are also excellent entry points into your own research. Narrow the Topic The narrower your topic, the easier it will be to limit the number of sources you need to read in order to obtain a good survey of relevant resources. Your professor will probably not expect you to read everything that's available about the topic, but you'll make the act of reviewing easier if you first limit scope of the research problem. A good strategy is to begin by searching the USC Libraries Catalog for recent books about the topic and review the table of contents for chapters that focuses on specific issues. You can also review the indexes of books to find references to specific issues that can serve as the focus of your research. For example, a book surveying the history of the Israeli-Palestinian conflict may include a chapter on the role Egypt has played in mediating the conflict, or look in the index for the pages where Egypt is mentioned in the text. Consider Whether Your Sources are Current Some disciplines require that you use information that is as current as possible. This is particularly true in disciplines in medicine and the sciences where research conducted becomes obsolete very quickly as new discoveries are made. However, when writing a review in the social sciences, a survey of the history of the literature may be required. In other words, a complete understanding the research problem requires you to deliberately examine how knowledge and perspectives have changed over time. Sort through other current bibliographies or literature reviews in the field to get a sense of what your discipline expects. You can also use this method to explore what is considered by scholars to be a "hot topic" and what is not.

III.  Ways to Organize Your Literature Review

Chronology of Events If your review follows the chronological method, you could write about the materials according to when they were published. This approach should only be followed if a clear path of research building on previous research can be identified and that these trends follow a clear chronological order of development. For example, a literature review that focuses on continuing research about the emergence of German economic power after the fall of the Soviet Union. By Publication Order your sources by publication chronology, then, only if the order demonstrates a more important trend. For instance, you could order a review of literature on environmental studies of brown fields if the progression revealed, for example, a change in the soil collection practices of the researchers who wrote and/or conducted the studies. Thematic [“conceptual categories”] A thematic literature review is the most common approach to summarizing prior research in the social and behavioral sciences. Thematic reviews are organized around a topic or issue, rather than the progression of time, although the progression of time may still be incorporated into a thematic review. For example, a review of the Internet’s impact on American presidential politics could focus on the development of online political satire. While the study focuses on one topic, the Internet’s impact on American presidential politics, it would still be organized chronologically reflecting technological developments in media. The difference in this example between a "chronological" and a "thematic" approach is what is emphasized the most: themes related to the role of the Internet in presidential politics. Note that more authentic thematic reviews tend to break away from chronological order. A review organized in this manner would shift between time periods within each section according to the point being made. Methodological A methodological approach focuses on the methods utilized by the researcher. For the Internet in American presidential politics project, one methodological approach would be to look at cultural differences between the portrayal of American presidents on American, British, and French websites. Or the review might focus on the fundraising impact of the Internet on a particular political party. A methodological scope will influence either the types of documents in the review or the way in which these documents are discussed.

Other Sections of Your Literature Review Once you've decided on the organizational method for your literature review, the sections you need to include in the paper should be easy to figure out because they arise from your organizational strategy. In other words, a chronological review would have subsections for each vital time period; a thematic review would have subtopics based upon factors that relate to the theme or issue. However, sometimes you may need to add additional sections that are necessary for your study, but do not fit in the organizational strategy of the body. What other sections you include in the body is up to you. However, only include what is necessary for the reader to locate your study within the larger scholarship about the research problem.

Here are examples of other sections, usually in the form of a single paragraph, you may need to include depending on the type of review you write:

• Current Situation : Information necessary to understand the current topic or focus of the literature review.
• Sources Used : Describes the methods and resources [e.g., databases] you used to identify the literature you reviewed.
• History : The chronological progression of the field, the research literature, or an idea that is necessary to understand the literature review, if the body of the literature review is not already a chronology.
• Selection Methods : Criteria you used to select (and perhaps exclude) sources in your literature review. For instance, you might explain that your review includes only peer-reviewed [i.e., scholarly] sources.
• Standards : Description of the way in which you present your information.
• Questions for Further Research : What questions about the field has the review sparked? How will you further your research as a result of the review?

IV.  Writing Your Literature Review

Once you've settled on how to organize your literature review, you're ready to write each section. When writing your review, keep in mind these issues.

Use Evidence A literature review section is, in this sense, just like any other academic research paper. Your interpretation of the available sources must be backed up with evidence [citations] that demonstrates that what you are saying is valid. Be Selective Select only the most important points in each source to highlight in the review. The type of information you choose to mention should relate directly to the research problem, whether it is thematic, methodological, or chronological. Related items that provide additional information, but that are not key to understanding the research problem, can be included in a list of further readings . Use Quotes Sparingly Some short quotes are appropriate if you want to emphasize a point, or if what an author stated cannot be easily paraphrased. Sometimes you may need to quote certain terminology that was coined by the author, is not common knowledge, or taken directly from the study. Do not use extensive quotes as a substitute for using your own words in reviewing the literature. Summarize and Synthesize Remember to summarize and synthesize your sources within each thematic paragraph as well as throughout the review. Recapitulate important features of a research study, but then synthesize it by rephrasing the study's significance and relating it to your own work and the work of others. Keep Your Own Voice While the literature review presents others' ideas, your voice [the writer's] should remain front and center. For example, weave references to other sources into what you are writing but maintain your own voice by starting and ending the paragraph with your own ideas and wording. Use Caution When Paraphrasing When paraphrasing a source that is not your own, be sure to represent the author's information or opinions accurately and in your own words. Even when paraphrasing an author’s work, you still must provide a citation to that work.

V.  Common Mistakes to Avoid

These are the most common mistakes made in reviewing social science research literature.

• Sources in your literature review do not clearly relate to the research problem;
• You do not take sufficient time to define and identify the most relevant sources to use in the literature review related to the research problem;
• Relies exclusively on secondary analytical sources rather than including relevant primary research studies or data;
• Uncritically accepts another researcher's findings and interpretations as valid, rather than examining critically all aspects of the research design and analysis;
• Does not describe the search procedures that were used in identifying the literature to review;
• Reports isolated statistical results rather than synthesizing them in chi-squared or meta-analytic methods; and,
• Only includes research that validates assumptions and does not consider contrary findings and alternative interpretations found in the literature.

Cook, Kathleen E. and Elise Murowchick. “Do Literature Review Skills Transfer from One Course to Another?” Psychology Learning and Teaching 13 (March 2014): 3-11; Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Jesson, Jill. Doing Your Literature Review: Traditional and Systematic Techniques . London: SAGE, 2011; Literature Review Handout. Online Writing Center. Liberty University; Literature Reviews. The Writing Center. University of North Carolina; Onwuegbuzie, Anthony J. and Rebecca Frels. Seven Steps to a Comprehensive Literature Review: A Multimodal and Cultural Approach . Los Angeles, CA: SAGE, 2016; Ridley, Diana. The Literature Review: A Step-by-Step Guide for Students . 2nd ed. Los Angeles, CA: SAGE, 2012; Randolph, Justus J. “A Guide to Writing the Dissertation Literature Review." Practical Assessment, Research, and Evaluation. vol. 14, June 2009; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016; Taylor, Dena. The Literature Review: A Few Tips On Conducting It. University College Writing Centre. University of Toronto; Writing a Literature Review. Academic Skills Centre. University of Canberra.

Writing Tip

Break Out of Your Disciplinary Box!

Thinking interdisciplinarily about a research problem can be a rewarding exercise in applying new ideas, theories, or concepts to an old problem. For example, what might cultural anthropologists say about the continuing conflict in the Middle East? In what ways might geographers view the need for better distribution of social service agencies in large cities than how social workers might study the issue? You don’t want to substitute a thorough review of core research literature in your discipline for studies conducted in other fields of study. However, particularly in the social sciences, thinking about research problems from multiple vectors is a key strategy for finding new solutions to a problem or gaining a new perspective. Consult with a librarian about identifying research databases in other disciplines; almost every field of study has at least one comprehensive database devoted to indexing its research literature.

Frodeman, Robert. The Oxford Handbook of Interdisciplinarity . New York: Oxford University Press, 2010.

Another Writing Tip

Don't Just Review for Content!

While conducting a review of the literature, maximize the time you devote to writing this part of your paper by thinking broadly about what you should be looking for and evaluating. Review not just what scholars are saying, but how are they saying it. Some questions to ask:

• How are they organizing their ideas?
• What methods have they used to study the problem?
• What theories have been used to explain, predict, or understand their research problem?
• What sources have they cited to support their conclusions?
• How have they used non-textual elements [e.g., charts, graphs, figures, etc.] to illustrate key points?

When you begin to write your literature review section, you'll be glad you dug deeper into how the research was designed and constructed because it establishes a means for developing more substantial analysis and interpretation of the research problem.

Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1 998.

Yet Another Writing Tip

When Do I Know I Can Stop Looking and Move On?

Here are several strategies you can utilize to assess whether you've thoroughly reviewed the literature:

• Look for repeating patterns in the research findings . If the same thing is being said, just by different people, then this likely demonstrates that the research problem has hit a conceptual dead end. At this point consider: Does your study extend current research?  Does it forge a new path? Or, does is merely add more of the same thing being said?
• Look at sources the authors cite to in their work . If you begin to see the same researchers cited again and again, then this is often an indication that no new ideas have been generated to address the research problem.
• Search Google Scholar to identify who has subsequently cited leading scholars already identified in your literature review [see next sub-tab]. This is called citation tracking and there are a number of sources that can help you identify who has cited whom, particularly scholars from outside of your discipline. Here again, if the same authors are being cited again and again, this may indicate no new literature has been written on the topic.

Onwuegbuzie, Anthony J. and Rebecca Frels. Seven Steps to a Comprehensive Literature Review: A Multimodal and Cultural Approach . Los Angeles, CA: Sage, 2016; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016.

• << Previous: Theoretical Framework
• Next: Citation Tracking >>
• Last Updated: Jun 18, 2024 10:45 AM
• URL: https://libguides.usc.edu/writingguide

• UConn Library
• Literature Review: The What, Why and How-to Guide
• Introduction

Literature Review: The What, Why and How-to Guide — Introduction

• Getting Started
• How to Pick a Topic
• Strategies to Find Sources
• Evaluating Sources & Lit. Reviews
• Tips for Writing Literature Reviews
• Writing Literature Review: Useful Sites
• Citation Resources
• Other Academic Writings

What are Literature Reviews?

So, what is a literature review? "A literature review is an account of what has been published on a topic by accredited scholars and researchers. In writing the literature review, your purpose is to convey to your reader what knowledge and ideas have been established on a topic, and what their strengths and weaknesses are. As a piece of writing, the literature review must be defined by a guiding concept (e.g., your research objective, the problem or issue you are discussing, or your argumentative thesis). It is not just a descriptive list of the material available, or a set of summaries." Taylor, D.  The literature review: A few tips on conducting it . University of Toronto Health Sciences Writing Centre.

Goals of Literature Reviews

What are the goals of creating a Literature Review?  A literature could be written to accomplish different aims:

• To develop a theory or evaluate an existing theory
• To summarize the historical or existing state of a research topic
• Identify a problem in a field of research 

Baumeister, R. F., & Leary, M. R. (1997). Writing narrative literature reviews .  Review of General Psychology , 1 (3), 311-320.

What kinds of sources require a Literature Review?

• A research paper assigned in a course
• A thesis or dissertation
• A grant proposal
• An article intended for publication in a journal

All these instances require you to collect what has been written about your research topic so that you can demonstrate how your own research sheds new light on the topic.

Types of Literature Reviews

What kinds of literature reviews are written?

Narrative review: The purpose of this type of review is to describe the current state of the research on a specific topic/research and to offer a critical analysis of the literature reviewed. Studies are grouped by research/theoretical categories, and themes and trends, strengths and weakness, and gaps are identified. The review ends with a conclusion section which summarizes the findings regarding the state of the research of the specific study, the gaps identify and if applicable, explains how the author's research will address gaps identify in the review and expand the knowledge on the topic reviewed.

• Example : Predictors and Outcomes of U.S. Quality Maternity Leave: A Review and Conceptual Framework:  10.1177/08948453211037398  

Systematic review : "The authors of a systematic review use a specific procedure to search the research literature, select the studies to include in their review, and critically evaluate the studies they find." (p. 139). Nelson, L. K. (2013). Research in Communication Sciences and Disorders . Plural Publishing.

• Example : The effect of leave policies on increasing fertility: a systematic review:  10.1057/s41599-022-01270-w

Meta-analysis : "Meta-analysis is a method of reviewing research findings in a quantitative fashion by transforming the data from individual studies into what is called an effect size and then pooling and analyzing this information. The basic goal in meta-analysis is to explain why different outcomes have occurred in different studies." (p. 197). Roberts, M. C., & Ilardi, S. S. (2003). Handbook of Research Methods in Clinical Psychology . Blackwell Publishing.

• Example : Employment Instability and Fertility in Europe: A Meta-Analysis:  10.1215/00703370-9164737

Meta-synthesis : "Qualitative meta-synthesis is a type of qualitative study that uses as data the findings from other qualitative studies linked by the same or related topic." (p.312). Zimmer, L. (2006). Qualitative meta-synthesis: A question of dialoguing with texts .  Journal of Advanced Nursing , 53 (3), 311-318.

• Example : Women’s perspectives on career successes and barriers: A qualitative meta-synthesis:  10.1177/05390184221113735

Literature Reviews in the Health Sciences

• UConn Health subject guide on systematic reviews Explanation of the different review types used in health sciences literature as well as tools to help you find the right review type
• << Previous: Getting Started
• Next: How to Pick a Topic >>
• Last Updated: Sep 21, 2022 2:16 PM
• URL: https://guides.lib.uconn.edu/literaturereview

Research Methods

• Getting Started
• Literature Review Research
• Research Design
• Research Design By Discipline
• SAGE Research Methods
• Teaching with SAGE Research Methods

Literature Review

• What is a Literature Review?
• What is NOT a Literature Review?
• Purposes of a Literature Review
• Types of Literature Reviews
• Literature Reviews vs. Systematic Reviews
• Systematic vs. Meta-Analysis

Literature Review  is a comprehensive survey of the works published in a particular field of study or line of research, usually over a specific period of time, in the form of an in-depth, critical bibliographic essay or annotated list in which attention is drawn to the most significant works.

Also, we can define a literature review as the collected body of scholarly works related to a topic:

• Summarizes and analyzes previous research relevant to a topic
• Includes scholarly books and articles published in academic journals
• Can be an specific scholarly paper or a section in a research paper

The objective of a Literature Review is to find previous published scholarly works relevant to an specific topic

• Help gather ideas or information
• Keep up to date in current trends and findings
• Help develop new questions

A literature review is important because it:

• Explains the background of research on a topic.
• Demonstrates why a topic is significant to a subject area.
• Helps focus your own research questions or problems
• Discovers relationships between research studies/ideas.
• Suggests unexplored ideas or populations
• Identifies major themes, concepts, and researchers on a topic.
• Tests assumptions; may help counter preconceived ideas and remove unconscious bias.
• Identifies critical gaps, points of disagreement, or potentially flawed methodology or theoretical approaches.
• Indicates potential directions for future research.

All content in this section is from Literature Review Research from Old Dominion University 

Keep in mind the following, a literature review is NOT:

Not an essay 

Not an annotated bibliography  in which you summarize each article that you have reviewed.  A literature review goes beyond basic summarizing to focus on the critical analysis of the reviewed works and their relationship to your research question.

Not a research paper   where you select resources to support one side of an issue versus another.  A lit review should explain and consider all sides of an argument in order to avoid bias, and areas of agreement and disagreement should be highlighted.

A literature review serves several purposes. For example, it

• provides thorough knowledge of previous studies; introduces seminal works.
• helps focus one’s own research topic.
• identifies a conceptual framework for one’s own research questions or problems; indicates potential directions for future research.
• suggests previously unused or underused methodologies, designs, quantitative and qualitative strategies.
• identifies gaps in previous studies; identifies flawed methodologies and/or theoretical approaches; avoids replication of mistakes.
• helps the researcher avoid repetition of earlier research.
• suggests unexplored populations.
• determines whether past studies agree or disagree; identifies controversy in the literature.
• tests assumptions; may help counter preconceived ideas and remove unconscious bias.

As Kennedy (2007) notes*, it is important to think of knowledge in a given field as consisting of three layers. First, there are the primary studies that researchers conduct and publish. Second are the reviews of those studies that summarize and offer new interpretations built from and often extending beyond the original studies. Third, there are the perceptions, conclusions, opinion, and interpretations that are shared informally that become part of the lore of field. In composing a literature review, it is important to note that it is often this third layer of knowledge that is cited as "true" even though it often has only a loose relationship to the primary studies and secondary literature reviews.

Given this, while literature reviews are designed to provide an overview and synthesis of pertinent sources you have explored, there are several approaches to how they can be done, depending upon the type of analysis underpinning your study. Listed below are definitions of types of literature reviews:

Argumentative Review      This form examines literature selectively in order to support or refute an argument, deeply imbedded assumption, or philosophical problem already established in the literature. The purpose is to develop a body of literature that establishes a contrarian viewpoint. Given the value-laden nature of some social science research [e.g., educational reform; immigration control], argumentative approaches to analyzing the literature can be a legitimate and important form of discourse. However, note that they can also introduce problems of bias when they are used to to make summary claims of the sort found in systematic reviews.

Integrative Review      Considered a form of research that reviews, critiques, and synthesizes representative literature on a topic in an integrated way such that new frameworks and perspectives on the topic are generated. The body of literature includes all studies that address related or identical hypotheses. A well-done integrative review meets the same standards as primary research in regard to clarity, rigor, and replication.

Historical Review      Few things rest in isolation from historical precedent. Historical reviews are focused on examining research throughout a period of time, often starting with the first time an issue, concept, theory, phenomena emerged in the literature, then tracing its evolution within the scholarship of a discipline. The purpose is to place research in a historical context to show familiarity with state-of-the-art developments and to identify the likely directions for future research.

Methodological Review      A review does not always focus on what someone said [content], but how they said it [method of analysis]. This approach provides a framework of understanding at different levels (i.e. those of theory, substantive fields, research approaches and data collection and analysis techniques), enables researchers to draw on a wide variety of knowledge ranging from the conceptual level to practical documents for use in fieldwork in the areas of ontological and epistemological consideration, quantitative and qualitative integration, sampling, interviewing, data collection and data analysis, and helps highlight many ethical issues which we should be aware of and consider as we go through our study.

Systematic Review      This form consists of an overview of existing evidence pertinent to a clearly formulated research question, which uses pre-specified and standardized methods to identify and critically appraise relevant research, and to collect, report, and analyse data from the studies that are included in the review. Typically it focuses on a very specific empirical question, often posed in a cause-and-effect form, such as "To what extent does A contribute to B?"

Theoretical Review      The purpose of this form is to concretely examine the corpus of theory that has accumulated in regard to an issue, concept, theory, phenomena. The theoretical literature review help establish what theories already exist, the relationships between them, to what degree the existing theories have been investigated, and to develop new hypotheses to be tested. Often this form is used to help establish a lack of appropriate theories or reveal that current theories are inadequate for explaining new or emerging research problems. The unit of analysis can focus on a theoretical concept or a whole theory or framework.

* Kennedy, Mary M. "Defining a Literature."  Educational Researcher  36 (April 2007): 139-147.

All content in this section is from The Literature Review created by Dr. Robert Larabee USC

Robinson, P. and Lowe, J. (2015),  Literature reviews vs systematic reviews.  Australian and New Zealand Journal of Public Health, 39: 103-103. doi: 10.1111/1753-6405.12393

What's in the name? The difference between a Systematic Review and a Literature Review, and why it matters . By Lynn Kysh from University of Southern California

Systematic review or meta-analysis?

A  systematic review  answers a defined research question by collecting and summarizing all empirical evidence that fits pre-specified eligibility criteria.

A  meta-analysis  is the use of statistical methods to summarize the results of these studies.

Systematic reviews, just like other research articles, can be of varying quality. They are a significant piece of work (the Centre for Reviews and Dissemination at York estimates that a team will take 9-24 months), and to be useful to other researchers and practitioners they should have:

• clearly stated objectives with pre-defined eligibility criteria for studies
• explicit, reproducible methodology
• a systematic search that attempts to identify all studies
• assessment of the validity of the findings of the included studies (e.g. risk of bias)
• systematic presentation, and synthesis, of the characteristics and findings of the included studies

Not all systematic reviews contain meta-analysis. 

Meta-analysis is the use of statistical methods to summarize the results of independent studies. By combining information from all relevant studies, meta-analysis can provide more precise estimates of the effects of health care than those derived from the individual studies included within a review.  More information on meta-analyses can be found in  Cochrane Handbook, Chapter 9 .

A meta-analysis goes beyond critique and integration and conducts secondary statistical analysis on the outcomes of similar studies.  It is a systematic review that uses quantitative methods to synthesize and summarize the results.

An advantage of a meta-analysis is the ability to be completely objective in evaluating research findings.  Not all topics, however, have sufficient research evidence to allow a meta-analysis to be conducted.  In that case, an integrative review is an appropriate strategy. 

Some of the content in this section is from Systematic reviews and meta-analyses: step by step guide created by Kate McAllister.

• << Previous: Getting Started
• Next: Research Design >>
• Last Updated: Aug 21, 2023 4:07 PM
• URL: https://guides.lib.udel.edu/researchmethods

Methodological Approaches to Literature Review

• Living reference work entry
• First Online: 09 May 2023
• Cite this living reference work entry

• Dennis Thomas 2 ,
• Elida Zairina 3 &
• Johnson George 4  

589 Accesses

1 Citations

The literature review can serve various functions in the contexts of education and research. It aids in identifying knowledge gaps, informing research methodology, and developing a theoretical framework during the planning stages of a research study or project, as well as reporting of review findings in the context of the existing literature. This chapter discusses the methodological approaches to conducting a literature review and offers an overview of different types of reviews. There are various types of reviews, including narrative reviews, scoping reviews, and systematic reviews with reporting strategies such as meta-analysis and meta-synthesis. Review authors should consider the scope of the literature review when selecting a type and method. Being focused is essential for a successful review; however, this must be balanced against the relevance of the review to a broad audience.

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Institutional subscriptions

Akobeng AK. Principles of evidence based medicine. Arch Dis Child. 2005;90(8):837–40.

Article   CAS   PubMed   PubMed Central   Google Scholar  

Alharbi A, Stevenson M. Refining Boolean queries to identify relevant studies for systematic review updates. J Am Med Inform Assoc. 2020;27(11):1658–66.

Article   PubMed   PubMed Central   Google Scholar  

Arksey H, O’Malley L. Scoping studies: towards a methodological framework. Int J Soc Res Methodol. 2005;8(1):19–32.

Article   Google Scholar  

Aromataris E MZE. JBI manual for evidence synthesis. 2020.

Google Scholar  

Aromataris E, Pearson A. The systematic review: an overview. Am J Nurs. 2014;114(3):53–8.

Article   PubMed   Google Scholar  

Aromataris E, Riitano D. Constructing a search strategy and searching for evidence. A guide to the literature search for a systematic review. Am J Nurs. 2014;114(5):49–56.

Babineau J. Product review: covidence (systematic review software). J Canad Health Libr Assoc Canada. 2014;35(2):68–71.

Baker JD. The purpose, process, and methods of writing a literature review. AORN J. 2016;103(3):265–9.

Bastian H, Glasziou P, Chalmers I. Seventy-five trials and eleven systematic reviews a day: how will we ever keep up? PLoS Med. 2010;7(9):e1000326.

Bramer WM, Rethlefsen ML, Kleijnen J, Franco OH. Optimal database combinations for literature searches in systematic reviews: a prospective exploratory study. Syst Rev. 2017;6(1):1–12.

Brown D. A review of the PubMed PICO tool: using evidence-based practice in health education. Health Promot Pract. 2020;21(4):496–8.

Cargo M, Harris J, Pantoja T, et al. Cochrane qualitative and implementation methods group guidance series – paper 4: methods for assessing evidence on intervention implementation. J Clin Epidemiol. 2018;97:59–69.

Cook DJ, Mulrow CD, Haynes RB. Systematic reviews: synthesis of best evidence for clinical decisions. Ann Intern Med. 1997;126(5):376–80.

Article   CAS   PubMed   Google Scholar  

Counsell C. Formulating questions and locating primary studies for inclusion in systematic reviews. Ann Intern Med. 1997;127(5):380–7.

Cummings SR, Browner WS, Hulley SB. Conceiving the research question and developing the study plan. In: Cummings SR, Browner WS, Hulley SB, editors. Designing Clinical Research: An Epidemiological Approach. 4th ed. Philadelphia (PA): P Lippincott Williams & Wilkins; 2007. p. 14–22.

Eriksen MB, Frandsen TF. The impact of patient, intervention, comparison, outcome (PICO) as a search strategy tool on literature search quality: a systematic review. JMLA. 2018;106(4):420.

Ferrari R. Writing narrative style literature reviews. Medical Writing. 2015;24(4):230–5.

Flemming K, Booth A, Hannes K, Cargo M, Noyes J. Cochrane qualitative and implementation methods group guidance series – paper 6: reporting guidelines for qualitative, implementation, and process evaluation evidence syntheses. J Clin Epidemiol. 2018;97:79–85.

Grant MJ, Booth A. A typology of reviews: an analysis of 14 review types and associated methodologies. Health Inf Libr J. 2009;26(2):91–108.

Green BN, Johnson CD, Adams A. Writing narrative literature reviews for peer-reviewed journals: secrets of the trade. J Chiropr Med. 2006;5(3):101–17.

Gregory AT, Denniss AR. An introduction to writing narrative and systematic reviews; tasks, tips and traps for aspiring authors. Heart Lung Circ. 2018;27(7):893–8.

Harden A, Thomas J, Cargo M, et al. Cochrane qualitative and implementation methods group guidance series – paper 5: methods for integrating qualitative and implementation evidence within intervention effectiveness reviews. J Clin Epidemiol. 2018;97:70–8.

Harris JL, Booth A, Cargo M, et al. Cochrane qualitative and implementation methods group guidance series – paper 2: methods for question formulation, searching, and protocol development for qualitative evidence synthesis. J Clin Epidemiol. 2018;97:39–48.

Higgins J, Thomas J. In: Chandler J, Cumpston M, Li T, Page MJ, Welch VA, editors. Cochrane Handbook for Systematic Reviews of Interventions version 6.3, updated February 2022). Available from www.training.cochrane.org/handbook.: Cochrane; 2022.

International prospective register of systematic reviews (PROSPERO). Available from https://www.crd.york.ac.uk/prospero/ .

Khan KS, Kunz R, Kleijnen J, Antes G. Five steps to conducting a systematic review. J R Soc Med. 2003;96(3):118–21.

Landhuis E. Scientific literature: information overload. Nature. 2016;535(7612):457–8.

Lockwood C, Porritt K, Munn Z, Rittenmeyer L, Salmond S, Bjerrum M, Loveday H, Carrier J, Stannard D. Chapter 2: Systematic reviews of qualitative evidence. In: Aromataris E, Munn Z, editors. JBI Manual for Evidence Synthesis. JBI; 2020. Available from https://synthesismanual.jbi.global . https://doi.org/10.46658/JBIMES-20-03 .

Chapter   Google Scholar  

Lorenzetti DL, Topfer L-A, Dennett L, Clement F. Value of databases other than medline for rapid health technology assessments. Int J Technol Assess Health Care. 2014;30(2):173–8.

Moher D, Liberati A, Tetzlaff J, Altman DG, the PRISMA Group. Preferred reporting items for (SR) and meta-analyses: the PRISMA statement. Ann Intern Med. 2009;6:264–9.

Mulrow CD. Systematic reviews: rationale for systematic reviews. BMJ. 1994;309(6954):597–9.

Munn Z, Peters MDJ, Stern C, Tufanaru C, McArthur A, Aromataris E. Systematic review or scoping review? Guidance for authors when choosing between a systematic or scoping review approach. BMC Med Res Methodol. 2018;18(1):143.

Munthe-Kaas HM, Glenton C, Booth A, Noyes J, Lewin S. Systematic mapping of existing tools to appraise methodological strengths and limitations of qualitative research: first stage in the development of the CAMELOT tool. BMC Med Res Methodol. 2019;19(1):1–13.

Murphy CM. Writing an effective review article. J Med Toxicol. 2012;8(2):89–90.

NHMRC. Guidelines for guidelines: assessing risk of bias. Available at https://nhmrc.gov.au/guidelinesforguidelines/develop/assessing-risk-bias . Last published 29 August 2019. Accessed 29 Aug 2022.

Noyes J, Booth A, Cargo M, et al. Cochrane qualitative and implementation methods group guidance series – paper 1: introduction. J Clin Epidemiol. 2018b;97:35–8.

Noyes J, Booth A, Flemming K, et al. Cochrane qualitative and implementation methods group guidance series – paper 3: methods for assessing methodological limitations, data extraction and synthesis, and confidence in synthesized qualitative findings. J Clin Epidemiol. 2018a;97:49–58.

Noyes J, Booth A, Moore G, Flemming K, Tunçalp Ö, Shakibazadeh E. Synthesising quantitative and qualitative evidence to inform guidelines on complex interventions: clarifying the purposes, designs and outlining some methods. BMJ Glob Health. 2019;4(Suppl 1):e000893.

Peters MD, Godfrey CM, Khalil H, McInerney P, Parker D, Soares CB. Guidance for conducting systematic scoping reviews. Int J Evid Healthcare. 2015;13(3):141–6.

Polanin JR, Pigott TD, Espelage DL, Grotpeter JK. Best practice guidelines for abstract screening large-evidence systematic reviews and meta-analyses. Res Synth Methods. 2019;10(3):330–42.

Article   PubMed Central   Google Scholar  

Shea BJ, Grimshaw JM, Wells GA, et al. Development of AMSTAR: a measurement tool to assess the methodological quality of systematic reviews. BMC Med Res Methodol. 2007;7(1):1–7.

Shea BJ, Reeves BC, Wells G, et al. AMSTAR 2: a critical appraisal tool for systematic reviews that include randomised or non-randomised studies of healthcare interventions, or both. Brit Med J. 2017;358

Sterne JA, Hernán MA, Reeves BC, et al. ROBINS-I: a tool for assessing risk of bias in non-randomised studies of interventions. Br Med J. 2016;355

Stroup DF, Berlin JA, Morton SC, et al. Meta-analysis of observational studies in epidemiology: a proposal for reporting. JAMA. 2000;283(15):2008–12.

Tawfik GM, Dila KAS, Mohamed MYF, et al. A step by step guide for conducting a systematic review and meta-analysis with simulation data. Trop Med Health. 2019;47(1):1–9.

The Critical Appraisal Program. Critical appraisal skills program. Available at https://casp-uk.net/ . 2022. Accessed 29 Aug 2022.

The University of Melbourne. Writing a literature review in Research Techniques 2022. Available at https://students.unimelb.edu.au/academic-skills/explore-our-resources/research-techniques/reviewing-the-literature . Accessed 29 Aug 2022.

The Writing Center University of Winconsin-Madison. Learn how to write a literature review in The Writer’s Handbook – Academic Professional Writing. 2022. Available at https://writing.wisc.edu/handbook/assignments/reviewofliterature/ . Accessed 29 Aug 2022.

Thompson SG, Sharp SJ. Explaining heterogeneity in meta-analysis: a comparison of methods. Stat Med. 1999;18(20):2693–708.

Tricco AC, Lillie E, Zarin W, et al. A scoping review on the conduct and reporting of scoping reviews. BMC Med Res Methodol. 2016;16(1):15.

Tricco AC, Lillie E, Zarin W, et al. PRISMA extension for scoping reviews (PRISMA-ScR): checklist and explanation. Ann Intern Med. 2018;169(7):467–73.

Yoneoka D, Henmi M. Clinical heterogeneity in random-effect meta-analysis: between-study boundary estimate problem. Stat Med. 2019;38(21):4131–45.

Yuan Y, Hunt RH. Systematic reviews: the good, the bad, and the ugly. Am J Gastroenterol. 2009;104(5):1086–92.

Download references

Author information

Authors and affiliations.

Centre of Excellence in Treatable Traits, College of Health, Medicine and Wellbeing, University of Newcastle, Hunter Medical Research Institute Asthma and Breathing Programme, Newcastle, NSW, Australia

Dennis Thomas

Department of Pharmacy Practice, Faculty of Pharmacy, Universitas Airlangga, Surabaya, Indonesia

Elida Zairina

Centre for Medicine Use and Safety, Monash Institute of Pharmaceutical Sciences, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia

Johnson George

You can also search for this author in PubMed   Google Scholar

Corresponding author

Correspondence to Johnson George .

Section Editor information

College of Pharmacy, Qatar University, Doha, Qatar

Derek Charles Stewart

Department of Pharmacy, University of Huddersfield, Huddersfield, United Kingdom

Zaheer-Ud-Din Babar

Rights and permissions

Reprints and permissions

Copyright information

© 2023 Springer Nature Switzerland AG

About this entry

Cite this entry.

Thomas, D., Zairina, E., George, J. (2023). Methodological Approaches to Literature Review. In: Encyclopedia of Evidence in Pharmaceutical Public Health and Health Services Research in Pharmacy. Springer, Cham. https://doi.org/10.1007/978-3-030-50247-8_57-1

Download citation

DOI : https://doi.org/10.1007/978-3-030-50247-8_57-1

Received : 22 February 2023

Accepted : 22 February 2023

Published : 09 May 2023

Publisher Name : Springer, Cham

Print ISBN : 978-3-030-50247-8

Online ISBN : 978-3-030-50247-8

eBook Packages : Springer Reference Biomedicine and Life Sciences Reference Module Biomedical and Life Sciences

• Publish with us

Policies and ethics

• Find a journal
• Track your research

Harvey Cushing/John Hay Whitney Medical Library

• Collections
• Research Help

YSN Doctoral Programs: Steps in Conducting a Literature Review

• Biomedical Databases
• Global (Public Health) Databases
• Soc. Sci., History, and Law Databases
• Grey Literature
• Trials Registers
• Data and Statistics
• Public Policy
• Google Tips
• Recommended Books
• Steps in Conducting a Literature Review

What is a literature review?

A literature review is an integrated analysis -- not just a summary-- of scholarly writings and other relevant evidence related directly to your research question.  That is, it represents a synthesis of the evidence that provides background information on your topic and shows a association between the evidence and your research question.

A literature review may be a stand alone work or the introduction to a larger research paper, depending on the assignment.  Rely heavily on the guidelines your instructor has given you.

Why is it important?

A literature review is important because it:

• Explains the background of research on a topic.
• Demonstrates why a topic is significant to a subject area.
• Discovers relationships between research studies/ideas.
• Identifies major themes, concepts, and researchers on a topic.
• Identifies critical gaps and points of disagreement.
• Discusses further research questions that logically come out of the previous studies.

APA7 Style resources

APA Style Blog - for those harder to find answers

1. Choose a topic. Define your research question.

Your literature review should be guided by your central research question.  The literature represents background and research developments related to a specific research question, interpreted and analyzed by you in a synthesized way.

• Make sure your research question is not too broad or too narrow.  Is it manageable?
• Begin writing down terms that are related to your question. These will be useful for searches later.
• If you have the opportunity, discuss your topic with your professor and your class mates.

2. Decide on the scope of your review

How many studies do you need to look at? How comprehensive should it be? How many years should it cover? 

• This may depend on your assignment.  How many sources does the assignment require?

3. Select the databases you will use to conduct your searches.

Make a list of the databases you will search. 

Where to find databases:

• use the tabs on this guide
• Find other databases in the Nursing Information Resources web page
• More on the Medical Library web page
• ... and more on the Yale University Library web page

4. Conduct your searches to find the evidence. Keep track of your searches.

• Use the key words in your question, as well as synonyms for those words, as terms in your search. Use the database tutorials for help.
• Save the searches in the databases. This saves time when you want to redo, or modify, the searches. It is also helpful to use as a guide is the searches are not finding any useful results.
• Review the abstracts of research studies carefully. This will save you time.
• Use the bibliographies and references of research studies you find to locate others.
• Check with your professor, or a subject expert in the field, if you are missing any key works in the field.
• Ask your librarian for help at any time.
• Use a citation manager, such as EndNote as the repository for your citations. See the EndNote tutorials for help.

Review the literature

Some questions to help you analyze the research:

• What was the research question of the study you are reviewing? What were the authors trying to discover?
• Was the research funded by a source that could influence the findings?
• What were the research methodologies? Analyze its literature review, the samples and variables used, the results, and the conclusions.
• Does the research seem to be complete? Could it have been conducted more soundly? What further questions does it raise?
• If there are conflicting studies, why do you think that is?
• How are the authors viewed in the field? Has this study been cited? If so, how has it been analyzed?

Tips: 

• Review the abstracts carefully.  
• Keep careful notes so that you may track your thought processes during the research process.
• Create a matrix of the studies for easy analysis, and synthesis, across all of the studies.
• << Previous: Recommended Books
• Last Updated: Jan 4, 2024 10:52 AM
• URL: https://guides.library.yale.edu/YSNDoctoral

• Subject guides
• Researching for your literature review
• Literature sources

Researching for your literature review: Literature sources

• Literature reviews
• Before you start
• Develop a search strategy
• Keyword search activity
• Subject search activity
• Combined keyword and subject searching
• Online tutorials
• Apply search limits
• Run a search in different databases
• Supplementary searching
• Save your searches
• Manage results

Scholarly databases

It's important to make a considered decision as to where to search for your review of the literature. It's uncommon for a disciplinary area to be covered by a single publisher, so searching a single publisher platform or database is unlikely to give you sufficient coverage of studies for a review. A good quality literature review involves searching a number of databases individually.

The most common method is to search a combination of large inter-disciplinary databases such as Scopus & Web of Science Core Collection, and some subject-specific databases (such as PsycInfo or EconLit etc.). The Library databases are an excellent place to start for sources of peer-reviewed journal articles.

Depending on disciplinary expectations, or the topic of our review, you may also need to consider sources or search methods other than database searching. There is general information below on searching grey literature. However, due to the wide varieties of grey literature available, you may need to spend some time investigating sources relevant for your specific need.

Grey literature

Grey literature is information which has been published informally or non-commercially (where the main purpose of the producing body is not commercial publishing) or remains unpublished. One example may be Government publications.

Grey literature may be included in a literature review to minimise publication bias . The quality of grey literature can vary greatly - some may be peer reviewed whereas some may not have been through a traditional editorial process.

See the Grey Literature guide for further information on finding and evaluating grey sources.

See the Moodle book MNHS: Systematically searching the grey literature for a comprehensive module on grey literature for systematic reviews.

In certain disciplines (such as physics) there can be a culture of preprints being made available prior to submissions to journals. There has also been a noticeable rise in preprints in medical and health areas in the wake of Covid-19.

If preprints are relevant for you, you can search preprint servers directly. A workaround might be to utilise a search engine such as Google Scholar to search specifically for preprints, as Google Scholar has timely coverage of most preprint servers including ArXiv, RePec, SSRN, BioRxiv, and MedRxiv.

Articles in Press are not preprints, but are accepted manuscripts that are not yet formally published. Articles in Press have been made available as an early access online version of a paper that may not yet have received its final formatting or an allocation of a volume/issue number. As well as being available on a journal's website, Articles in Press are available in databases such as Scopus and Web of Science, and so (unlike preprints) don't necessarily require a separate search.

Conference papers

Conference papers are typically published in conference proceedings (the collection of papers presented at a conference), and may be found on an organisation or Society's website, as a journal, or as a special issue of journal.

In certain disciplines (such as computer science), conference papers may be highly regarded as a form of scholarly communication; the conferences are highly selective, the papers are generally peer reviewed, and papers are published in proceedings affiliated with high-quality publishing houses.

Conference papers may be indexed in a range of scholarly databases. If you only want to see conference papers, database limits can be used to filter results, or try a specific index such as the examples below:

• Conference proceedings citation index. Social science & humanities (CPCI-SSH)
• Conference proceedings citation index. Science (CPCI-S)
• ASME digital library conference proceedings

Honours students and postgraduates may request conference papers through Interlibrary Loans . However, conference paper requests may take longer than traditional article requests as they can be difficult to locate; they may have been only supplied to attendees or not formally published. Sometimes only the abstract is available.

If you are specifically looking for statistical data, try searching for the keyword statistics in a Google Advanced Search and limiting by a relevant site or domain. Below are some examples of sites, or you can try a domain such as .gov for government websites.

Statistical data can be found in the following selected sources:

• Australian Bureau of Statistics
• World Health Organization: Health Data and statistics
• Higher Education Statistics
• UNESCO Institute for Statistics
• Tourism Australia Statistics

For a list of databases that include statistics see: Databases by Subject: Statistics .

If you are specifically looking for information found in newspapers, the library has a large collection of Australian and overseas newspapers, both current and historical.

To search the full-text of newspapers in electronic format use a database such as  Newsbank.

Alternatively, see the Newspapers subject guide for comprehensive information on newspaper sources available via Monash University library and open source databases, as well as searching tips, online videos and more.

Dissertations and theses

The Monash University Library Theses subject guide provides resources and guidelines for locating and accessing theses (dissertations) produced by Monash University as well as other universities in Australia and internationally.  

International theses:

There are a number of theses databases and repositories.

A popular source is:

• ProQuest Dissertations & Theses Global  which predominantly, covers North American masters and doctoral theses. Full text is available for theses added since 1997. 

Australia and New Zealand theses:

Theses that are available in the library can be found using the  Search catalogue.

These include:

• Monash doctoral, masters and a small number of honours theses 
• other Australian and overseas theses that have been purchased for the collection.

Formats include print (not available for loan), microfiche and online (some may have access restrictions).

Trove includes doctoral, masters and some honours theses from all Australian and New Zealand universities, as well as theses awarded elsewhere but held by Australian institutions.

Tips:  

• Type in the title, author surname and/or keywords. Then on the results page refine your search to 'thesis'.
• Alternatively, use the Advanced search and include 'thesis' as a keyword or limi t your result to format = thesis
• << Previous: Literature reviews
• Next: Before you start >>

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

Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now .

• Advanced Search
• Journal List
• Indian J Anaesth
• v.60(9); 2016 Sep

Literature search for research planning and identification of research problem

Anju grewal.

Department of Anaesthesiology, Dayanand Medical College and Hospital, Ludhiana, Punjab, India

Hanish Kataria

1 Department of Surgery, Government Medical College and Hospital, Chandigarh, India

2 Department of Cardiac Anaesthesia, All India Institute of Medical Sciences, New Delhi, India

Literature search is a key step in performing good authentic research. It helps in formulating a research question and planning the study. The available published data are enormous; therefore, choosing the appropriate articles relevant to your study in question is an art. It can be time-consuming, tiring and can lead to disinterest or even abandonment of search in between if not carried out in a step-wise manner. Various databases are available for performing literature search. This article primarily stresses on how to formulate a research question, the various types and sources for literature search, which will help make your search specific and time-saving.

INTRODUCTION

Literature search is a systematic and well-organised search from the already published data to identify a breadth of good quality references on a specific topic.[ 1 ] The reasons for conducting literature search are numerous that include drawing information for making evidence-based guidelines, a step in the research method and as part of academic assessment.[ 2 ] However, the main purpose of a thorough literature search is to formulate a research question by evaluating the available literature with an eye on gaps still amenable to further research.

Research problem[ 3 ] is typically a topic of interest and of some familiarity to the researcher. It needs to be channelised by focussing on information yet to be explored. Once we have narrowed down the problem, seeking and analysing existing literature may further straighten out the research approach.

A research hypothesis[ 4 ] is a carefully created testimony of how you expect the research to proceed. It is one of the most important tools which aids to answer the research question. It should be apt containing necessary components, and raise a question that can be tested and investigated.

The literature search can be exhaustive and time-consuming, but there are some simple steps which can help you plan and manage the process. The most important are formulating the research questions and planning your search.

FORMULATING THE RESEARCH QUESTION

Literature search is done to identify appropriate methodology, design of the study; population sampled and sampling methods, methods of measuring concepts and techniques of analysis. It also helps in determining extraneous variables affecting the outcome and identifying faults or lacunae that could be avoided.

Formulating a well-focused question is a critical step for facilitating good clinical research.[ 5 ] There can be general questions or patient-oriented questions that arise from clinical issues. Patient-oriented questions can involve the effect of therapy or disease or examine advantage versus disadvantage for a group of patients.[ 6 ]

For example, we want to evaluate the effect of a particular drug (e.g., dexmedetomidine) for procedural sedation in day care surgery patients. While formulating a research question, one should consider certain criteria, referred as ‘FINER’ (F-Feasible, I-Interesting, N-Novel, E-Ethical, R-Relevant) criteria.[ 5 ] The idea should be interesting and relevant to clinical research. It should either confirm, refute or add information to already done research work. One should also keep in mind the patient population under study and the resources available in a given set up. Also the entire research process should conform to the ethical principles of research.

The patient or study population, intervention, comparison or control arm, primary outcome, timing of measurement of outcome (PICOT) is a well-known approach for framing a leading research question.[ 7 , 8 ] Dividing the questions into key components makes it easy and searchable. In this case scenario:

• Patients (P) – What is the important group of patients? for example, day care surgery
• Intervention (I) – What is the important intervention? for example, intravenous dexmedetomidine
• Comparison (C) – What is the important intervention of comparison? for example, intravenous ketamine
• Outcome (O) – What is the effect of intervention? for example, analgesic efficacy, procedural awareness, drug side effects
• Time (T) – Time interval for measuring the outcome: Hourly for first 4 h then 4 hourly till 24 h post-procedure.

Multiple questions can be formulated from patient's problem and concern. A well-focused question should be chosen for research according to significance for patient interest and relevance to our knowledge. Good research questions address the lacunae in available literature with an aim to impact the clinical practice in a constructive manner. There are limited outcome research and relevant resources, for example, electronic database system, database and hospital information system in India. Even when these factors are available, data about existing resources is not widely accessible.[ 9 ]

TYPES OF MEDICAL LITERATURE

(Further details in chapter ‘Types of studies and research design’ in this issue).

Primary literature

Primary sources are the authentic publication of an expert's new evidence, conclusions and proposals (case reports, clinical trials, etc) and are usually published in a peer-reviewed journal. Preliminary reports, congress papers and preprints also constitute primary literature.[ 2 ]

Secondary literature

Secondary sources are systematic review articles or meta-analyses where material derived from primary source literature are infererred and evaluated.[ 2 ]

Tertiary literature

Tertiary literature consists of collections that compile information from primary or secondary literature (eg., reference books).[ 2 ]

METHODS OF LITERATURE SEARCH

There are various methods of literature search that are used alone or in combination [ Table 1 ]. For past few decades, searching the local as well as national library for books, journals, etc., was the usual practice and still physical literature exploration is an important component of any systematic review search process.[ 10 , 11 ] With the advancement of technology, the Internet is now the gateway to the maze of vast medical literature.[ 12 ] Conducting a literature review involves web-based search engines, i.e., Google, Google Scholar, etc., [ Table 2 ], or using various electronic research databases to identify materials that describe the research topic or those homologous to it.[ 13 , 14 ]

Methods of literature search

Web based methods of literature search

The various databases available for literature search include databases for original published articles in the journals [ Table 2 ] and evidence-based databases for integrated information available as systematic reviews and abstracts [ Table 3 ].[ 12 , 14 ] Most of these are not freely available to the individual user. PubMed ( http://www.ncbi.nlm.nih.gov/pubmed/ ) is the largest available resource since 1996; however, a large number of sources now provide free access to literature in the biomedical field.[ 15 ] More than 26 million citations from Medline, life science journals and online books are included in PubMed. Links to the full-text material are included in citations from PubMed Central and publisher web sites.[ 16 ] The choice of databases depends on the subject of interest and potential coverage by the different databases. Education Resources Information Centre is a free online digital library of education research and information sponsored by the Institute of Education Sciences of the U.S. Department of Education, available at http://eric.ed.gov/ . No one database can search all the medical literature. There is need to search several different databases. At a minimum, PubMed or Medline, Embase and the Cochrane central trials Registry need to be searched. When searching these databases, emphasis should be given to meta-analysis, systematic reviews randomised controlled trials and landmark studies.

Electronic source of Evidence-Based Database

Time allocated to the search needs attention as exploring and selecting data are early steps in the research method and research conducted as part of academic assessment have narrow timeframes.[ 17 ] In Indian scenario, limited outcome research and accessibility to data leads to less thorough knowledge of nature of research problem. This results in the formulation of the inappropriate research question and increases the time to literature search.

TYPES OF SEARCH

Type of search can be described in different forms according to the subject of interest. It increases the chances of retrieving relevant information from a search.

Translating research question to keywords

This will provide results based on any of the words specified; hence, they are the cornerstone of an effective search. Synonyms/alternate terms should be considered to elicit further information, i.e., barbiturates in place of thiopentone. Spellings should also be taken into account, i.e., anesthesia in place of anaesthesia (American and British). Most databases use controlled word-stock to establish common search terms (or keywords). Some of these alternative keywords can be looked from database thesaurus.[ 4 ] Another strategy is combining keywords with Boolean operators. It is important to keep a note of keywords and methods used in exploring the literature as these will need to be described later in the design of search process.

‘Medical Subject Heading (MeSH) is the National Library of Medicine's controlled hierarchical vocabulary that is used for indexing articles in PubMed, with more specific terms organised underneath more general terms’.[ 17 ] This provides a reliable way to retrieve citations that use different terminology for identical ideas, as it indexes articles based on content. Two features of PubMed that can increase yield of specific articles are ‘Automatic term mapping’ and ‘automatic term explosion’.[ 4 ]

For example, if the search keyword is heart attack, this term will match with MeSH transcription table heading and then explode into various subheadings. This helps to construct the search by adding and selecting MeSH subheadings and families of MeSH by use of hyperlinks.[ 4 ]

We can set limits to a clinical trial for retrieving higher level of evidence (i.e., randomised controlled clinical trial). Furthermore, one can browse through the link entitled ‘Related Articles’. This PubMed feature searches for similar citations using an intricate algorithm that scans titles, abstracts and MeSH terms.[ 4 ]

Phrase search

This will provide pages with only the words typed in the phrase, in that exact order and with no words in between them.

Boolean operators

AND, OR and NOT are the three Boolean operators named after the mathematician George Boole.[ 18 ] Combining two words using ‘AND’ will fetch articles that mention both the words. Using ‘OR’ will widen the search and fetch more articles that mention either subject. While using the term ‘NOT’ to combine words will fetch articles containing the first word but not the second, thus narrowing the search.

Filters can also be used to refine the search, for example, article types, text availability, language, age, sex and journal categories.

Overall, the recommendations for methodology of literature search can be as below (Creswell)[ 19 ]

• Identify keywords and use them to search articles from library and internet resources as described above
• Search several databases to search articles related to your topic
• Use thesaurus to identify terms to locate your articles
• Find an article that is similar to your topic; then look at the terms used to describe it, and use them for your search
• Use databases that provide full-text articles (free through academic libraries, Internet or for a fee) as much as possible so that you can save time searching for your articles
• If you are examining a topic for the first time and unaware of the research on it, start with broad syntheses of the literature, such as overviews, summaries of the literature on your topic or review articles
• Start with the most recent issues of the journals, and look for studies about your topic and then work backward in time. Follow-up on references at the end of the articles for more sources to examine
• Refer books on a single topic by a single author or group of authors or books that contain chapters written by different authors
• Next look for recent conference papers. Often, conference papers report the latest research developments. Contact authors of pertinent studies. Write or phone them, asking if they know of studies related to your area of interest
• The easy access and ability to capture entire articles from the web make it attractive. However, check these articles carefully for authenticity and quality and be cautious about whether they represent systematic research.

The whole process of literature search[ 20 ] is summarised in Figure 1 .

Process of literature search

Literature search provides not only an opportunity to learn more about a given topic but provides insight on how the topic was studied by previous analysts. It helps to interpret ideas, detect shortcomings and recognise opportunities. In short, systematic and well-organised research may help in designing a novel research.

Financial support and sponsorship

Conflicts of interest.

There are no conflicts of interest.

5.3 Acceptable sources for literature reviews

Following are a few acceptable sources for literature reviews, listed in order from what will be considered most acceptable to less acceptable sources for your literature review assignments:

• Peer reviewed journal articles.
• Edited academic books.
• Articles in professional journals.
• Statistical data from government websites.
• Website material from professional associations (use sparingly and carefully). The following sections will explain and provide examples of these various sources.

Peer reviewed journal articles (papers)

A peer reviewed journal article is a paper that has been submitted to a scholarly journal, accepted, and published. Peer review journal papers go through a rigorous, blind review process of peer review. What this means is that two to three experts in the area of research featured in the paper have reviewed and accepted the paper for publication. The names of the author(s) who are seeking to publish the research have been removed (blind review), so as to minimize any bias towards the authors of the research (albeit, sometimes a savvy reviewer can discern who has done the research based upon previous publications, etc.). This blind review process can be long (often 12 to 18 months) and may involve many back and forth edits on the behalf of the researchers, as they work to address the edits and concerns of the peers who reviewed their paper. Often, reviewers will reject the paper for a variety of reasons, such as unclear or questionable methods, lack of contribution to the field, etc. Because peer reviewed journal articles have gone through a rigorous process of review, they are considered to be the premier source for research. Peer reviewed journal articles should serve as the foundation for your literature review.

The following link will provide more information on peer reviewed journal articles. Make sure you watch the little video on the upper left-hand side of your screen, in addition to reading the material at the following website:    http://guides.lib.jjay.cuny.edu/c.php?g=288333&p=1922599

Edited academic books

An edited academic book is a collection of scholarly scientific papers written by different authors. The works are original papers, not published elsewhere (“Edited volume,” 2018). The papers within the text also go through a process of review; however, the review is often not a blind review because the authors have been invited to contribute to the book. Consequently, edited academic books are fine to use for your literature review, but you also want to ensure that your literature review contains mostly peer reviewed journal papers.

Articles in professional journals

Articles from professional journals should be used with caution for your literature review. This is because articles in trade journals are not usually peer reviewed, even though they may appear to be. A good way to find out is to read the “About Us” section of the professional journal, which should state whether or not the papers are peer reviewed. You can also find out by Googling the name of the journal and adding “peer reviewed” to the search.

Statistical data from governmental websites

Governmental websites can be excellent sources for statistical data, e.g, Statistics Canada collects and publishes data related to the economy, society, and the environment (see https://www.statcan.gc.ca/eng/start ).

Website material from professional associations

Material from other websites can also serve as a source for statistics that you may need for your literature review. Since you want to justify the value of the research that interests you, you might make use of a professional association’s website to learn how many members they have, for example. You might want to demonstrate, as part of the introduction to your literature review, why more research on the topic of PTSD in police officers is important. You could use peer reviewed journal articles to determine the prevalence of PTSD in police officers in Canada in the last ten years, and then use the Ontario Police Officers´ Association website to determine the approximate number of police officers employed in the Province of Ontario over the last ten years. This might help you estimate how many police officers could be suffering with PTSD in Ontario. That number could potentially help to justify a research grant down the road. But again, this type of website- based material should be used with caution and sparingly.

Research Methods for the Social Sciences: An Introduction Copyright © 2020 by Valerie Sheppard is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License , except where otherwise noted.

Share This Book

Explore millions of high-quality primary sources and images from around the world, including artworks, maps, photographs, and more.

Explore migration issues through a variety of media types

• Part of The Streets are Talking: Public Forms of Creative Expression from Around the World
• Part of The Journal of Economic Perspectives, Vol. 34, No. 1 (Winter 2020)
• Part of Cato Institute (Aug. 3, 2021)
• Part of University of California Press
• Part of Open: Smithsonian National Museum of African American History & Culture
• Part of Indiana Journal of Global Legal Studies, Vol. 19, No. 1 (Winter 2012)
• Part of R Street Institute (Nov. 1, 2020)
• Part of Leuven University Press
• Part of UN Secretary-General Papers: Ban Ki-moon (2007-2016)
• Part of Perspectives on Terrorism, Vol. 12, No. 4 (August 2018)
• Part of Leveraging Lives: Serbia and Illegal Tunisian Migration to Europe, Carnegie Endowment for International Peace (Mar. 1, 2023)
• Part of UCL Press

Harness the power of visual materials—explore more than 3 million images now on JSTOR.

Enhance your scholarly research with underground newspapers, magazines, and journals.

Explore collections in the arts, sciences, and literature from the world’s leading museums, archives, and scholars.

Have a language expert improve your writing

Run a free plagiarism check in 10 minutes, generate accurate citations for free.

• Knowledge Base
• Working with sources
• Types of Sources Explained | Examples & Tips

Types of Sources Explained | Examples & Tips

Published on May 19, 2022 by Eoghan Ryan . Revised on May 31, 2023.

Throughout the research process , you’ll likely use various types of sources . The source types commonly used in academic writing include:

Academic journals

• Encyclopedias

Table of contents

Primary, secondary, and tertiary sources, other interesting articles, frequently asked questions about types of sources.

Academic journals are the most up-to-date sources in academia. They’re typically published multiple times a year and contain cutting-edge research. Consult academic journals to find the most current debates and research topics in your field.

There are many kinds of journal articles, including:

• Original research articles: These publish original data ( primary sources )
• Theoretical articles: These contribute to the theoretical foundations of a field.
• Review articles: These summarize the current state of the field.

Credible journals use peer review . This means that experts in the field assess the quality and credibility of an article before it is published. Journal articles include a full bibliography and use scholarly or technical language.

Academic journals are usually published online, and sometimes also in print. Consult your institution’s library to find out what academic journals they provide access to.

  Learn how to cite a journal article

Prevent plagiarism. Run a free check.

Academic books are great sources to use when you need in-depth information on your research or dissertation topic .

They’re typically written by experts and provide an extensive overview and analysis of a specific topic. They can be written by a single author or by multiple authors contributing individual chapters (often overseen by a general editor).

Books published by respected academic publishing houses and university presses are typically considered trustworthy sources. Academic books usually include a full bibliography and use scholarly or technical language. Books written for more general audiences are less relevant in an academic context.

Books can be accessed online or in print. Your institution’s library will likely contain access to a wide selection of each.

Learn how to cite a book

Websites are great sources for preliminary research and can help you to learn more about a topic you’re new to.

However, they are not always credible sources . Many websites don’t provide the author’s name, so it can be hard to tell if they’re an expert. Websites often don’t cite their sources, and they typically don’t subject their content to peer review.

For these reasons, you should carefully consider whether any web sources you use are appropriate to cite or not. Some websites are more credible than others. Look for DOIs or trusted domain extensions:

• URLs that end with .edu are specifically educational resources.
• URLs that end with .gov are government-related

Both of these are typically considered trustworthy.

Learn how to cite a website

Newspapers can be valuable sources, providing insights on current or past events and trends.

However, news articles are not always reliable and may be written from a biased perspective or with the intention of promoting a political agenda. News articles usually do not cite their sources and are written for a popular, rather than academic, audience.

Nevertheless, newspapers can help when you need information on recent topics or events that have not been the subject of in-depth academic study. Archives of older newspapers can also be useful sources for historical research.

Newspapers are published in both digital and print form. Consult your institution’s library to find out what newspaper archives they provide access to.

Learn how to cite a newspaper article

Don't submit your assignments before you do this

The academic proofreading tool has been trained on 1000s of academic texts. Making it the most accurate and reliable proofreading tool for students. Free citation check included.

Try for free

Encyclopedias are reference works that contain summaries or overviews of topics rather than original insights. These overviews are presented in alphabetical order.

Although they’re often written by experts, encyclopedia entries are not typically attributed to a single author and don’t provide the specialized knowledge expected of scholarly sources. As a result, they’re best used as sources of background information at the beginning of your research. You can then expand your knowledge by consulting more academic sources.

Encyclopedias can be general or subject-specific:

• General encyclopedias contain entries on diverse topics.
• Subject encyclopedias focus on a particular field and contain entries specific to that field (e.g., Western philosophy or molecular biology).

They can be found online (including crowdsourced encyclopedias like Wikipedia) or in print form.

Learn how to cite Wikipedia

Every source you use will be either a:

• Primary source : The source provides direct evidence about your topic (e.g., a news article).
• Secondary source : The source provides an interpretation or commentary on primary sources (e.g., a journal article).
• Tertiary source : The source summarizes or consolidates primary and secondary sources but does not provide additional analysis or insights (e.g., an encyclopedia).

Tertiary sources are often used for broad overviews at the beginning of a research project. Further along, you might look for primary and secondary sources that you can use to help formulate your position.

How each source is categorized depends on the topic of research and how you use the source.

If you want to know more about ChatGPT, AI tools , citation , and plagiarism , make sure to check out some of our other articles with explanations and examples.

• ChatGPT vs human editor
• ChatGPT citations
• Is ChatGPT trustworthy?
• Using ChatGPT for your studies
• What is ChatGPT?
• Chicago style
• Paraphrasing

 Plagiarism

• Types of plagiarism
• Self-plagiarism
• Avoiding plagiarism
• Academic integrity
• Consequences of plagiarism
• Common knowledge

There are many types of sources commonly used in research. These include:

• Journal articles

You’ll likely use a variety of these sources throughout the research process , and the kinds of sources you use will depend on your research topic and goals.

Scholarly sources are written by experts in their field and are typically subjected to peer review . They are intended for a scholarly audience, include a full bibliography, and use scholarly or technical language. For these reasons, they are typically considered credible sources .

Popular sources like magazines and news articles are typically written by journalists. These types of sources usually don’t include a bibliography and are written for a popular, rather than academic, audience. They are not always reliable and may be written from a biased or uninformed perspective, but they can still be cited in some contexts.

In academic writing, the sources you cite should be credible and scholarly. Some of the main types of sources used are:

• Academic journals: These are the most up-to-date sources in academia. They are published more frequently than books and provide cutting-edge research.
• Books: These are great sources to use, as they are typically written by experts and provide an extensive overview and analysis of a specific topic.

It is important to find credible sources and use those that you can be sure are sufficiently scholarly .

• Consult your institute’s library to find out what books, journals, research databases, and other types of sources they provide access to.
• Look for books published by respected academic publishing houses and university presses, as these are typically considered trustworthy sources.
• Look for journals that use a peer review process. This means that experts in the field assess the quality and credibility of an article before it is published.

Cite this Scribbr article

If you want to cite this source, you can copy and paste the citation or click the “Cite this Scribbr article” button to automatically add the citation to our free Citation Generator.

Ryan, E. (2023, May 31). Types of Sources Explained | Examples & Tips. Scribbr. Retrieved June 18, 2024, from https://www.scribbr.com/working-with-sources/types-of-sources/

Is this article helpful?

Eoghan Ryan

Other students also liked, primary vs. secondary sources | difference & examples, what are credible sources & how to spot them | examples, types of plagiarism and how to recognize them, "i thought ai proofreading was useless but..".

I've been using Scribbr for years now and I know it's a service that won't disappoint. It does a good job spotting mistakes”

Discover top guides, trends, tips and expertise from AIO Writers

Examples of Primary and Secondary Sources in Research

Julia McCoy

Imagine you’re a detective, piecing together clues from a mysterious event. Your leads? These are examples of primary and secondary sources .

In one hand, you hold an original letter penned by the suspect — that’s your primary source. It offers first-hand insights but also bears the author’s biases.

Then you have a newspaper article about the event – this is your secondary source. While it interprets information for you, it may not present every perspective.

Understanding these differences is key to effective research and writing.

This guide will help you decipher between these two types of sources, using practical examples along with tips on when and how best to use them in writing.

Table of Contents:

Primary sources vs. secondary sources, diaries and personal journals, letters and correspondence, official documents, original research reports, oral history interviews, photographs, creative works, autobiographies, eyewitness accounts, a range of secondary sources, the newspaper dilemma, books about events, academic critiques, documentary films, scholarly articles, a direct connection to the past, unfiltered, original content, drawing personal connections, promotes authenticity, fosters critical thinking, rewards curiosity with authenticity, serves multiple purposes in research, depth and diversity, provides context, evidence and support, wide range of sources, critical analysis, avoiding plagiarism, cross-referencing, legal and ethical considerations, documentaries, reviews and essays, newspaper articles, identify your research question or topic, locate relevant primary sources, evaluate authenticity and reliability, contextualize your sources, extract relevant information, analyze and interpret, integrate primary sources seamlessly, use quotations sparingly, create a bibliography or works cited page, provide proper attribution, cite properly, balance with secondary sources, locate relevant secondary sources, evaluate the quality of secondary sources, read and summarize, analyze and synthesize, maintain a critical stance, provide context and analysis, avoid plagiarism.

If you’re investigating an unfamiliar subject or doing research, it’s essential to use both primary and secondary sources. But what’s the difference? And why does it matter?

A primary source, to start with, gives first-hand information about an event, person, object, or work of art. It is typically created during the time under study by those who experienced the events being documented.

Primary sources include diaries recounting personal experiences in war zones or recordings of live concerts — raw data that hasn’t been processed yet.

Meanwhile, secondary sources provide interpretations and analyses based on primary sources. They are one step removed from these original accounts.

An example would be a biography about Beethoven which uses his letters (primary source) as references for insights into his life and work.

In essence, if we were detectives investigating a case, our primary source would be direct evidence like DNA samples, while secondary sources might include crime scene analysis reports. Both are vital but serve different purposes.

While this might seem straightforward at first glance, using them effectively requires skillful balance and understanding.

Examples of primary and secondary sources

Primary Source Examples

If you’re delving into research, primary sources are your first stop. They offer an unfiltered look at the subject matter, be it historical events or scientific discoveries. Here’s a glimpse of some types of primary sources.

A person’s intimate thoughts about their experiences can provide unparalleled insights.

For example, Anne Frank’s diary is a primary source documenting her life in hiding during the Nazi occupation in World War II.

The National Archives Catalog is filled with these types of firsthand accounts from different eras.

Personal letters, emails, or postcards exchanged between individuals can provide insight into historical events or personal relationships.

The words straight from the horse’s mouth — speeches by politicians or interviews with key figures — give us direct access to their views and opinions on matters they were part of.

Transcripts or recordings of speeches given by famous individuals are primary sources for understanding their ideas and influence.

Government documents, such as birth certificates, marriage licenses, passports, and treaties, are primary sources. 

For instance, the U.S. Declaration of Independence is an official document.

PubMed Central (PMC) houses millions of full-text biomedical literature articles, which are excellent examples of original research reports in medicine and life sciences.

Recorded interviews with individuals who lived through particular events or periods serve as primary sources. These can include eyewitness accounts.

Physical objects like clothing, tools, weapons, and archaeological findings are primary sources when studying cultures or historical periods.

Original photographs taken during a specific period can be primary sources. For example, photographs from the American Civil Rights Movement are primary sources that capture historical moments.

Poems, plays, novels, music pieces – these creative works reflect the author’s own imagination but also often draw upon their real-life experiences, making them valuable as primary sources, too.

Personal autobiographies and memoirs provide firsthand accounts of a person’s life and experiences.

In a digital age where everyone has a smartphone camera ready to capture happenings around them, live events or videos posted online serve as eyewitness accounts that are invaluable when investigating contemporary issues.

Now we’ve looked at various forms of primary sources, let me share an example of how an author might use primary sources to write a book on 20th-century pop culture. 

Imagine our author is writing a book about The Beatles. They might use transcripts from John Lennon’s interviews as a primary source. This would allow them to capture Lennon’s perspective on the band’s journey, their creative process, and what they stood for. These transcripts would be more than just information, but rather a peek into John’s mind during those times — raw, unfiltered insights that no secondary source could provide with such authenticity. 

So when you’re embarking on your next research project or simply want to learn more about a particular topic, start by looking at the primary sources available. They’re not just resources; they’re time capsules giving us an undiluted view of past events and people’s experiences.

Secondary Source Examples

Understanding secondary sources is essential for any research. Let’s use a classic scenario as an example: the tale of Little Red Riding Hood.

If you read the original Grimm Brothers’ story, that would be a primary source. But if you picked up a book discussing themes in fairy tales, that would be considered a secondary source.

Different fields have their own unique types of secondary sources. For instance:

• In history and literature studies, books providing analysis or interpretation are common secondary sources.
• In science and medicine, review articles summarizing multiple primary studies fall into this category.
• In law and political sciences, legal commentaries that offer interpretations of statutes or cases serve as examples of secondary resources.

Sometimes classifying documents can get tricky. Take newspapers, for example — they might seem like primary materials because they’re published immediately after events occur. But journalists usually aren’t direct witnesses to every event they cover; instead, they gather information from others.

Newspaper and online news articles that provide information and analysis of current events are considered secondary sources.

We often think all books are prime examples of secondary sources since most authors don’t directly experience what they’re writing about — especially when we talk about historical or scientific topics.

For instance, a history book discussing the causes of World War I is a secondary source.

Biographies, dictionaries , encyclopedias , and textbooks also count as secondary sources since they’re based on other original documents or firsthand accounts.

A critique of a novel, a movie review, or an article analyzing a research study are more examples of secondary sources. They provide analysis but aren’t the primary material themselves. Next time you read your favorite critic’s take on that latest blockbuster film, remember it’s another instance of a secondary source.

While they may include primary source footage, documentary films typically present an edited and interpreted view of historical events or issues.

Peer-reviewed academic journals that summarize, critique, or build upon existing research are secondary sources. Researchers use these to stay up-to-date with current scholarship.

A scholarly article, also known as a research or academic article, is a publication written by experts in a particular field. Journal articles typically present original research findings or analyses from studies conducted by the authors themselves.

In contrast to raw data collected for scientific experiments (which are primary sources), scholarly journal articles serve to interpret this information.

Here’s how you can easily identify examples of primary and secondary sources :

Does grammar matter when you’re citing sources? Learn more about what is grammar and why it matters  to your writing.

Benefits of Using Primary Sources

If you’ve ever had a burning question and decided to dig deeper for the answer, then you have likely encountered primary sources. But what makes these resources so valuable?

Primary sources offer a first-hand account or direct evidence about an event, object, person, or work of art. They are usually created by witnesses who experienced the events themselves. This provides an unparalleled perspective on historical events that secondary sources simply can’t match.

Primary sources allow writers to dig into the heart of events. They offer unfiltered access to information from its origin point — like reading an original letter by Abraham Lincoln , for instance. This rawness gives readers insight into the context that secondary sources may overlook.

An original letter written by Abraham Lincoln is considered a primary source .

A personal diary entry from World War II has more emotional impact than a textbook summarizing those years does. Primary data helps establish deeper connections between past experiences and current realities because they engage us on a more personal, emotional level.

Another advantage is credibility: when writers base their claims on direct evidence instead of relying on interpretations made by other authors through secondary source material, this makes them appear more authentic and reliable.

Using primary sources encourages critical thinking skills. It requires readers to analyze information from multiple viewpoints, interpret meanings, and make connections with other knowledge they possess. It essentially turns them into mini-historians.

In contrast to textbooks or summarized articles, primary sources present raw data as it was initially recorded — be it letters from soldiers during the American Civil War, photographs capturing key moments from the Great Depression, or audio recordings of Martin Luther King’s famous speeches. Their authenticity sparks curiosity while offering rich detail.

Beyond just providing factual details about an event, primary documents give insight into how people thought and felt at that time — helping researchers understand the cultural context better than any secondary source could do.

Remember: using such powerful tools responsibly is crucial; we must always approach them with an open mind, acknowledging their limitations and biases. But when used effectively, primary sources can be a treasure trove of knowledge that opens doors to new understanding and sparks deeper connections with the past.

Benefits of Using Secondary Sources

There are many advantages of citing secondary sources in your writing.

Secondary sources give your writing depth. They help you present a more rounded view by incorporating different perspectives on the topic. You can also get insights from experts, which add credibility to your arguments.

Some topics require a wide range of data or historical context that may not be feasible to collect firsthand. Secondary sources often provide this breadth of coverage.

Secondary sources can provide valuable context and background information on a topic. This helps your readers better understand the subject matter, especially if it’s complex or unfamiliar to them.

The use of secondary sources allows you to back up claims or ideas with evidence. This is especially useful when dealing with controversial subjects that require support for clarity and persuasiveness.

Well-established secondary sources such as peer-reviewed articles, books, and reputable websites often have a higher level of credibility compared to personal anecdotes or unsupported claims. This can enhance the reliability of your writing.

A biography — such as a book about Lincoln’s life — is a good example of a secondary source.

You can also use secondary sources to support and strengthen your arguments. By citing expert opinions, statistics, or relevant studies, you add weight to your claims and make your writing more persuasive.

Secondary sources encompass various formats such as academic journals, books, essays, documentaries, and news articles — each one offering a unique angle on a subject matter. This diversity enables you to draw information from different mediums to enrich your writing and provide readers with an engaging mix that keeps them hooked while learning.

Conducting primary research, such as surveys or interviews, can be time-consuming. Secondary sources allow you to access data and information that others have already gathered, saving you time and resources.

By cutting down long hours spent on data collection and interpretation, you can focus more on presenting compelling narratives in your writing.

Secondary sources often undergo rigorous review and scrutiny, which means they have been evaluated for their quality and validity. This allows you to engage in critical analysis and evaluation of the information you’re using.

Including expert commentary via secondary sources lets readers see various interpretations or criticisms about the topic at hand, making them think critically too.

Sometimes primary resources may leave gaps; there might be missing information or unexplained events. Secondary sources fill in these blanks and provide a fuller understanding.

Proper in-text citations of secondary sources serve as plagiarism checkers. By giving credit to the original authors of your data, you demonstrate academic integrity.

Secondary sources can lead you to other relevant sources. When you’re reading one secondary source, you may discover citations or references to additional materials that deepen your understanding of the subject.

In some cases, using secondary sources can help you navigate legal and ethical considerations, especially when dealing with sensitive topics or proprietary information.

However, it’s important to use secondary sources judiciously. Always evaluate the quality and reliability of the sources you choose, and be aware of potential biases.

Remember: a good mix of primary and secondary sources makes for well-rounded, compelling content. Balance secondary sources with primary research when appropriate, as primary sources can offer unique insights and original data that secondary sources may lack.

Examples of Primary and Secondary Sources in Different Contexts

The categorization of a source as primary or secondary can sometimes depend on the context of its use. For instance, a personal letter might be a primary source for a historian studying a specific individual but a secondary source for someone researching the historical context of the time. The distinction is not always rigid and can vary depending on the research question and purpose.

A secondary source can become a primary source based on your research question. If the individual, context, or method that created the source is the primary focus of your research, it becomes a primary source.

Here are examples of sources that can be primary or secondary.

If you are researching the causes of World War II, a recent documentary about it would be considered as a secondary source. However, if your focus shifts to filmmaking techniques used in historical documentaries instead, that same documentary becomes a primary source.

Another example involves literary studies. If your paper revolves around the work of Virginia Woolf, then any magazine review critiquing her work is categorized as a secondary resource. But suppose you’re studying critical reception towards her works; in that case, the review transforms into a primary resource.

A newspaper article discussing new economic policy falls under secondary resources when analyzing government policies. However, if we analyze how media covers economic issues, the same article becomes a primary resource.

As you can see, context is everything when it comes to classifying sources as primary or secondary. It all boils down to your research question and what you are trying to investigate.

When to use primary sources and secondary sources

How to Use Primary Sources in Writing

The use of primary sources can elevate your writing, giving it a level of authenticity and depth that secondary sources might not be able to provide. When you directly quote or reference firsthand documents, interviews, experiments, or original artworks, you are making sure your work is rooted in reality.

Here are a few tips on how to effectively use primary sources.

Before diving into primary sources, clearly define your research question or topic. What specific aspect are you investigating, and what information are you seeking?

Determine where and how to find primary sources related to your topic. These sources can include letters, diaries, photographs, official documents, interview transcripts, artifacts, and more.

• Libraries, archives, museums, historical societies, and digital repositories are common places to find primary sources. 
• Online databases and collections can also be valuable resources.

Assess the authenticity and reliability of your chosen primary sources. Consider the source’s origin, creator, date, and purpose. Ensure that the source is credible and relevant to your research.

Understand the historical or cultural context in which the primary sources were created. This background knowledge will help you interpret and analyze the sources accurately.

Extract the pertinent information or data from your primary sources. This may involve transcribing handwritten documents, summarizing interviews, or digitizing materials as needed.

Analyze the primary sources critically. Look for patterns, themes, contradictions, or significant details within the sources. Consider the biases or perspectives of the creators.

Connect the information from your primary sources to your research papers or thesis statement. How does each source contribute to your understanding of the topic?

Incorporate primary sources into your writing smoothly. Avoid merely dropping them into your text without explanation. Provide context and analysis to help your readers understand their relevance.

Use direct quotations from primary sources sparingly. It’s often more effective to paraphrase or summarize the content of the source in your own words, with appropriate citations.

Include a bibliography or works cited page at the end of your writing to list all the primary sources you used. Follow guidelines for appropriate citation formats.

Acknowledge the sources of your primary materials and give credit to their creators or owners. This demonstrates academic integrity and respects intellectual property rights.

When citing sources in your writing, follow the appropriate citation style. Popular citation styles include APA style, MLA style, or CMOS style. Include all necessary information, such as the source’s title, creator, date, and location.

Provide context within your text to explain the significance of the primary source and how it supports your argument or narrative.

Always check with your editor, teacher, or professor about what  citation style  to use

While primary sources provide valuable firsthand information, balance them with secondary sources to provide context, analysis, and expert opinions that support and complement your argument.

Remember that using primary sources effectively requires careful research, analysis, and citation. When done well, they can make your writing more compelling, original, and authoritative.

How to Use Secondary Sources in Writing

When it comes to writing, secondary sources are essential for adding depth and credibility. They offer an interpretation or analysis of primary source data and give your work depth and credibility. But how can you effectively use these resources?

Identify secondary sources that are relevant to your research. These can include books, scholarly articles, reports, reviews, and reputable websites. 

Use academic databases, library catalogs, and search engines to find these sources.

Assess the credibility and reliability of your chosen secondary sources. Consider the author’s qualifications, the publication source, peer-review status (for academic articles), and the date of publication. 

Aim to include sources from respected and authoritative authors or institutions.

Always cross-reference different secondary sources to avoid bias or misinterpretation.

Carefully read the secondary sources and summarize their main points, arguments, evidence, and conclusions. Note any key quotes or data that you may want to reference in your writing.

Analyze the secondary sources critically. Evaluate the author’s methodology, evidence, and arguments. Consider any biases or limitations in the source.

Synthesize the information from multiple secondary sources to identify common themes, conflicting viewpoints, or gaps in the existing literature. This will help you form a well-rounded understanding of your topic.

While secondary sources provide valuable insights, maintain a critical stance and be prepared to engage with differing viewpoints or critiques of the sources you reference.

When introducing secondary sources, provide context for your readers. Explain the significance of each source and how it relates to your research question or thesis.

Offer critical analysis of the secondary sources you reference. Discuss their strengths, weaknesses, and contributions to the overall understanding of your topic.

Properly attribute all ideas, information, and quotations from secondary sources. Plagiarism is a serious academic offense, so be sure to use quotation marks and cite sources accurately.

Use citations to attribute information, ideas, or quotes to the original sources.

Choose an appropriate citation style (e.g., APA, MLA, Chicago) to cite secondary sources in your writing.

Secondary sources can enhance the depth and credibility of your writing, as they provide context, analysis, and expert perspectives.

Always remember: they serve primarily as interpretive guides rather than factual accounts themselves.

These examples of primary and secondary sources are your detective tools in research. They help you piece together the full story.

Primary sources give you raw, first-hand data but may come with their author’s biases.

Secondary sources offer interpretation but may not cover all perspectives.

In writing or research, both have their place and benefits. The key is knowing when to use each for maximum impact.

To become a master researcher or writer, practice using these resources effectively — just like any skilled detective would do!

Written by Julia McCoy

UNLOCK YOUR POTENTIAL

Long headline that highlights value proposition of lead magnet.

Grab a front row seat to our video masterclasses, interviews, case studies, tutorials, and guides.

Experience the power of RankWell®

Grow Your Traffic!

Let's crawl your website and get you some keyword suggestions for your next piece of content.

By continuing, you agree with our Terms and Conditions.

Writing Lab

Research papers.

• Research Paper Basics
• Credible Sources
• Reading Scholarly Articles
• Summarizing and Paraphrasing
• Paraphrasing and Student Voice
• Direct Quotations
• Synthesis in Writing
• Citing Sources

How to Read an Academic Article

Sections of an academic article.

Most academic journal articles include the following sections:

• Abstract  (An executive summary of the study)
• Introduction (Definition of the research question to be studied)
• Literature Review (A summary of past research noting where gaps exist)
• Methods (The research design including variables, sample size, measurements)
• Data (Information gathered through the study often displayed in tables and charts)
• Results (Conclusions reached at the end of the study) Conclusion (Discussion of whether the study proved the thesis; may suggest opportunities for further research) Bibliography (A list of works cited in the journal article)

TIP: To begin selecting articles for your research, read the highlighted sections to determine whether the academic journal article includes information relevant to your research topic.

Step 1: Skim the Article

When sorting through multiple articles discovered in the research process, skimming through these sections of the article will help you determine whether the article will be useful in your research.

• Article title  and subject headings assigned to the article
• Introduction

If the article fits your information needs, go back and read the article thoroughly. TIP: Create a folder on your computer to save copies of articles you plan to use, and save your references.

Step 2: Determine Your Purpose

Think about how you will evaluate the academic articles you find and how you will determine whether to include them in your research project.  Ask yourself the following questions to focus your search in the academic literature: ​

• Are you looking for an overview of a topic or an explanation of a specific concept, idea, or position?
• Are you exploring gaps in the research to identify a new area for academic study?
• Are you looking for research that supports or disagrees with your thesis or research question?
• Are you looking for examples of a research design and/or research methods you are considering for your own research project?

Step 3: Read Critically

Before reading the article, ask yourself the following:

• What is my research question? What position am I trying to support?
• What do I already know about this topic?  What do I need to learn?
• How will I evaluate the article?  Author's reputation? Research design? Treatment of topic? 
• What are my biases about the topic?

As you read the article make note of the following:

• Who is the intended audience for this article?
• What is the author's purpose in writing this article?
• What is the main point?
• How was the main point proven or supported?  
• Were scientific methods used in conducting the research? Do you agree or disagree with the author? Why?
• How does this article compare or connect with other articles on the topic?
• Does the author recommend areas for further study?
• How does this article help to answer your research question?
• << Previous: Credible Sources
• Next: Summarizing and Paraphrasing >>
• Last Updated: Jun 14, 2024 9:44 AM
• URL: https://guides.rasmussen.edu/research-papers

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
• My Bibliography
• Collections
• Citation manager

Save citation to file

Email citation, add to collections.

• Create a new collection
• Add to an existing collection

Add to My Bibliography

Your saved search, create a file for external citation management software, your rss feed.

• Search in PubMed
• Search in NLM Catalog
• Add to Search

The Role of Magnesium in Sleep Health: a Systematic Review of Available Literature

Affiliations.

• 1 Department of Community Nutrition, School of Nutrition and Food Science, Food Security Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
• 2 Department of Clinical Nutrition, School of Nutrition and Food Science, Food Security Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
• 3 Food Security Research Center, Isfahan University of Medical Sciences, Hezar Jarib St., 8174673461, Isfahan, Iran. [email protected].
• PMID: 35184264
• DOI: 10.1007/s12011-022-03162-1

To date, no study has critically reviewed the current literature on the association between magnesium (Mg) and sleep health. Therefore, we carried out a systematic review to assess the association between Mg and sleep patterns in adults' population through observational and interventional studies. We searched for relevant studies through PubMed ( http://www.ncbi.nlm.nih.gov/pubmed ), Scopus ( http://www.scopus.com ), and ISI Web of Science ( http://www.webofscience.com ) from the earliest available date until November 2021. Eligibility criteria for study selection were guided by the following components identified using the PI(E)CO (Population, Intervention (Exposure), Comparison, Outcome) framework: P (adult population), I(E) (high dietary intake or supplementation of Mg), C (low dietary intake of Mg or placebo group), and O (sleep pattern including sleep duration, sleep-onset latency, night awakenings, sleep stages, and sleep phases). The present study involved 7,582 subjects from 9 published cross-sectional, cohort, and RCT systematically reviewed the possible links between Mg and sleep quality (daytime falling asleep, sleepiness, snoring, and sleep duration) in an adult population. Observational studies suggested an association between Mg statuses and sleep quality, while the RCTs reported contradictory findings. This systematic review revealed an association between magnesium status and sleep quality (daytime falling asleep, sleepiness, snoring, and sleep duration) according to the observational studies, while the randomized clinical trials showed an uncertain association between magnesium supplementation and sleep disorders. The association between dietary magnesium and sleep patterns needs well-designed randomized clinical trials with a larger sample size and longer follow-up time (more than 12 weeks) to further clarify the relationship.

Keywords: Magnesium; Nutrition; Sleep pattern; Sleep quality.

© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.

PubMed Disclaimer

Similar articles

• Myofunctional therapy (oropharyngeal exercises) for obstructive sleep apnoea. Rueda JR, Mugueta-Aguinaga I, Vilaró J, Rueda-Etxebarria M. Rueda JR, et al. Cochrane Database Syst Rev. 2020 Nov 3;11(11):CD013449. doi: 10.1002/14651858.CD013449.pub2. Cochrane Database Syst Rev. 2020. PMID: 33141943 Free PMC article.
• Magnesium Intake and Sleep Disorder Symptoms: Findings from the Jiangsu Nutrition Study of Chinese Adults at Five-Year Follow-Up. Cao Y, Zhen S, Taylor AW, Appleton S, Atlantis E, Shi Z. Cao Y, et al. Nutrients. 2018 Sep 21;10(10):1354. doi: 10.3390/nu10101354. Nutrients. 2018. PMID: 30248967 Free PMC article.
• Non-pharmacological interventions for sleep promotion in the intensive care unit. Hu RF, Jiang XY, Chen J, Zeng Z, Chen XY, Li Y, Huining X, Evans DJ. Hu RF, et al. Cochrane Database Syst Rev. 2015 Oct 6;2015(10):CD008808. doi: 10.1002/14651858.CD008808.pub2. Cochrane Database Syst Rev. 2015. PMID: 26439374 Free PMC article. Review.
• Short sleep duration, snoring and subjective sleep insufficiency are independent factors associated with both falling asleep and feeling sleepiness while driving. Abe T, Komada Y, Inoue Y. Abe T, et al. Intern Med. 2012;51(23):3253-60. doi: 10.2169/internalmedicine.51.7518. Epub 2012 Dec 1. Intern Med. 2012. PMID: 23207120
• Effects and side-effects of surgery for snoring and obstructive sleep apnea--a systematic review. Franklin KA, Anttila H, Axelsson S, Gislason T, Maasilta P, Myhre KI, Rehnqvist N. Franklin KA, et al. Sleep. 2009 Jan;32(1):27-36. Sleep. 2009. PMID: 19189776 Free PMC article. Review.
• Effect of Peanut Butter Intake on Sleep Health in Firefighters: A Randomized Controlled Trial. Oberther TJ, Moore AR, Kohler AA, Shuler DH, Peritore N, Holland-Winkler AM. Oberther TJ, et al. Int J Environ Res Public Health. 2024 Apr 29;21(5):571. doi: 10.3390/ijerph21050571. Int J Environ Res Public Health. 2024. PMID: 38791786 Free PMC article. Clinical Trial.
• The Impact of Chronic Magnesium Deficiency on Excitable Tissues-Translational Aspects. Stanojević M, Djuricic N, Parezanovic M, Biorac M, Pathak D, Spasic S, Lopicic S, Kovacevic S, Nesovic Ostojic J. Stanojević M, et al. Biol Trace Elem Res. 2024 May 6. doi: 10.1007/s12011-024-04216-2. Online ahead of print. Biol Trace Elem Res. 2024. PMID: 38709369 Review.
• Serum Calcium and Magnesium Levels, Not 25-Hydroxyvitamin D, Are Associated With Sleep Quality in Airline Pilots. Minoretti P, Santiago Sáez A, García Martín Á, Liaño Riera M, Gómez Serrano M, Emanuele E. Minoretti P, et al. Cureus. 2023 Dec 22;15(12):e50940. doi: 10.7759/cureus.50940. eCollection 2023 Dec. Cureus. 2023. PMID: 38259397 Free PMC article.
• Impact of Medical School on the Relationship between Nutritional Knowledge and Sleep Quality-A Longitudinal Study of Students at Wroclaw Medical University in Poland. Kosendiak AA, Adamczak BB, Kuźnik Z, Makles S. Kosendiak AA, et al. Nutrients. 2024 Jan 17;16(2):278. doi: 10.3390/nu16020278. Nutrients. 2024. PMID: 38257170 Free PMC article.
• Effects of Supplementing Zinc Magnesium Aspartate on Sleep Quality and Submaximal Weightlifting Performance, following Two Consecutive Nights of Partial Sleep Deprivation. Gallagher C, Austin V, Dunlop KA, Dally J, Taylor K, Pullinger SA, Edwards BJ. Gallagher C, et al. Nutrients. 2024 Jan 13;16(2):251. doi: 10.3390/nu16020251. Nutrients. 2024. PMID: 38257144 Free PMC article. Clinical Trial.
• Simonelli G, Marshall NS, Grillakis A, Miller CB, Hoyos CM, Glozier N (2018) Sleep health epidemiology in low and middle-income countries: a systematic review and meta-analysis of the prevalence of poor sleep quality and sleep duration. Sleep Health 4(3):239–250 - DOI
• Buxton OM, Marcelli E (2010) Short and long sleep are positively associated with obesity, diabetes, hypertension, and cardiovascular disease among adults in the United States. Soc Sci Med 71(5):1027–1036 - DOI
• Cappuccio FP, D’Elia L, Strazzullo P, Miller MA (2010) Sleep duration and all-cause mortality: a systematic review and meta-analysis of prospective studies. Sleep 33(5):585–592 - DOI
• Gallicchio L, Kalesan B (2009) Sleep duration and mortality: a systematic review and meta-analysis. J Sleep Res 18(2):148–158 - DOI
• Åkerstedt T, Fredlund P, Gillberg M, Jansson B (2002) A prospective study of fatal occupational accidents–relationship to sleeping difficulties and occupational factors. J Sleep Res 11(1):69–71 - DOI

Publication types

• Search in MeSH

Related information

• PubChem Compound (MeSH Keyword)

LinkOut - more resources

Full text sources.

• Archivio Istituzionale della Ricerca Unimi
• MedlinePlus Health Information

Research Materials

• NCI CPTC Antibody Characterization Program

Miscellaneous

• NCI CPTAC Assay Portal

• Citation Manager

NCBI Literature Resources

MeSH PMC Bookshelf Disclaimer

The PubMed wordmark and PubMed logo are registered trademarks of the U.S. Department of Health and Human Services (HHS). Unauthorized use of these marks is strictly prohibited.

• Biochemistry and Molecular Biology
• Biostatistics
• Environmental Health and Engineering
• Epidemiology
• Health Policy and Management
• Health, Behavior and Society
• International Health
• Mental Health
• Molecular Microbiology and Immunology
• Population, Family and Reproductive Health
• Program Finder
• Admissions Services
• Course Directory
• Academic Calendar
• Hybrid Campus
• Lecture Series
• Convocation
• Strategy and Development
• Implementation and Impact
• Integrity and Oversight
• In the School
• In the Field
• In Baltimore
• Resources for Practitioners
• Articles & News Releases
• In The News
• Statements & Announcements
• At a Glance
• Student Life
• Strategic Priorities
• Inclusion, Diversity, Anti-Racism, and Equity (IDARE)
• What is Public Health?

research@BSPH

The School’s research endeavors aim to improve the public’s health in the U.S. and throughout the world.

• Funding Opportunities and Support
• Faculty Innovation Award Winners

Conducting Research That Addresses Public Health Issues Worldwide

Systematic and rigorous inquiry allows us to discover the fundamental mechanisms and causes of disease and disparities. At our Office of Research ( research@BSPH), we translate that knowledge to develop, evaluate, and disseminate treatment and prevention strategies and inform public health practice. Research along this entire spectrum represents a fundamental mission of the Johns Hopkins Bloomberg School of Public Health.

From laboratories at Baltimore’s Wolfe Street building, to Bangladesh maternity wards in densely   packed neighborhoods, to field studies in rural Botswana, Bloomberg School faculty lead research that directly addresses the most critical public health issues worldwide. Research spans from molecules to societies and relies on methodologies as diverse as bench science and epidemiology. That research is translated into impact, from discovering ways to eliminate malaria, increase healthy behavior, reduce the toll of chronic disease, improve the health of mothers and infants, or change the biology of aging.

120+ countries

engaged in research activity by BSPH faculty and teams.

of all federal grants and contracts awarded to schools of public health are awarded to BSPH. 

citations on  publications where BSPH was listed in the authors' affiliation in 2019-2023. 

 publications where BSPH was listed in the authors' affiliation in 2019-2023.

Departments

Our 10 departments offer faculty and students the flexibility to focus on a variety of public health disciplines

Centers and Institutes Directory

Our 80+ Centers and Institutes provide a unique combination of breadth and depth, and rich opportunities for collaboration

Institutional Review Board (IRB)

The Institutional Review Board (IRB) oversees two IRBs registered with the U.S. Office of Human Research Protections, IRB X and IRB FC, which meet weekly to review human subjects research applications for Bloomberg School faculty and students

Generosity helps our community think outside the traditional boundaries of public health, working across disciplines and industries, to translate research into innovative health interventions and practices

Introducing the research@BSPH Ecosystem

The   research@BSPH   ecosystem aims to foster an interdependent sense of community among faculty researchers, their research teams, administration, and staff that leverages knowledge and develops shared responses to challenges. The ultimate goal is to work collectively to reduce administrative and bureaucratic barriers related to conducting experiments, recruiting participants, analyzing data, hiring staff,   and more, so that faculty can focus on their core academic pursuits.

Research at the Bloomberg School is a team sport.

In order to provide  extensive guidance, infrastructure, and support in pursuit of its research mission,   research@BSPH  employs three core areas: strategy and development, implementation and impact, and integrity and oversight. Our exceptional research teams comprised of faculty, postdoctoral fellows, students, and committed staff are united in our collaborative, collegial, and entrepreneurial approach to problem solving. T he Bloomberg School ensures that our research is accomplished according to the highest ethical standards and complies with all regulatory requirements. In addition to our institutional review board (IRB) which provides oversight for human subjects research, basic science studies employee techniques to ensure the reproducibility of research. 

Research@BSPH in the News

Four bloomberg school faculty elected to national academy of medicine.

Considered one of the highest honors in the fields of health and medicine, NAM membership recognizes outstanding professional achievements and commitment to service.

The Maryland Maternal Health Innovation Program Grant Renewed with Johns Hopkins

Lerner center for public health advocacy announces inaugural sommer klag advocacy impact award winners.

Bloomberg School faculty Nadia Akseer and Cass Crifasi selected winners at Advocacy Impact Awards Pitch Competition

To read this content please select one of the options below:

Please note you do not have access to teaching notes, improving the quality of student assessment practices: a saudi university case study.

Quality Assurance in Education

ISSN : 0968-4883

Article publication date: 19 June 2024

This paper aims to explore the best practices to institutionalize the internal quality of student assessment (SA) when a gap emerges between quality conceptualization and practice work, using Imam Abdul Rahman bin Faisal University (IAU) as a case study.

Design/methodology/approach

A single-embedded case study research design chronologically presents key events of assuring and improving SA at IAU. It integrates quantitative and qualitative data to provide empirical evidence of changes in SA practices.

Over three years, evident improvements in SA practices resulted in more effective internal quality assurance strategies (e.g., faculty involvement) and the achievement of performance indicators.

Research limitations/implications

This study used data from informal observation and self-reports. Thus, it is suggested that future research should use in-depth (e.g. focus group) and diverse data sources from stakeholders (e.g. students) and use emerging global trends to assess SA quality.

Practical implications

Involving faculty as changing agents via accountability and training in assuring and improving SA quality leads to measurable improvements.

Social implications

A top-down approach alone is insufficient to assure and improve the quality of SA practices, so empowering faculty via involvement and training is inevitable.

Originality/value

The quality assurance of SA described in this practice-oriented case places IAU as a leading university in the region, contributes to the external quality assurance of SA, empowers Saudi graduates to compete in the labor market as aspired in Vision 2030 and adds to the literature on quality assurance of SA in a higher education context.

• Student assessment
• Higher education

Acknowledgements

The extensive help and commitment of numerous individuals and entities within the institution were necessary for the accomplishment of this research. Since 2018, the heads of units for the quality of assessment and examinations at IAU have been working as changing agents of student assessment practices at IAU colleges, and for that, the authors are truly grateful. Moreover, the authors would like to extend their sincere gratitude to the administration of IAU colleges, whose support and commitment guaranteed the fulfilment of the performance indicators of the student assessment practices.

Mohamed, W. , Almuqayteeb, T. , Abd El Sattar, I. , Al-Ghamdi, T. and Alotaibi, G. (2024), "Improving the quality of student assessment practices: a Saudi University case study", Quality Assurance in Education , Vol. ahead-of-print No. ahead-of-print. https://doi.org/10.1108/QAE-10-2022-0186

Emerald Publishing Limited

Copyright © 2024, Emerald Publishing Limited

Related articles

We’re listening — tell us what you think, something didn’t work….

Report bugs here

All feedback is valuable

Please share your general feedback

Join us on our journey

Platform update page.

Visit emeraldpublishing.com/platformupdate to discover the latest news and updates

Questions & More Information

Answers to the most commonly asked questions here

• Introduction
• Article Information

eAppendix. Supplemental Methods

• Error in Table JAMA Network Open Correction March 9, 2021

See More About

Sign up for emails based on your interests, select your interests.

Customize your JAMA Network experience by selecting one or more topics from the list below.

• Academic Medicine
• Acid Base, Electrolytes, Fluids
• Allergy and Clinical Immunology
• American Indian or Alaska Natives
• Anesthesiology
• Anticoagulation
• Art and Images in Psychiatry
• Artificial Intelligence
• Assisted Reproduction
• Bleeding and Transfusion
• Caring for the Critically Ill Patient
• Challenges in Clinical Electrocardiography
• Climate and Health
• Climate Change
• Clinical Challenge
• Clinical Decision Support
• Clinical Implications of Basic Neuroscience
• Clinical Pharmacy and Pharmacology
• Complementary and Alternative Medicine
• Consensus Statements
• Coronavirus (COVID-19)
• Critical Care Medicine
• Cultural Competency
• Dental Medicine
• Dermatology
• Diabetes and Endocrinology
• Diagnostic Test Interpretation
• Drug Development
• Electronic Health Records
• Emergency Medicine
• End of Life, Hospice, Palliative Care
• Environmental Health
• Equity, Diversity, and Inclusion
• Facial Plastic Surgery
• Gastroenterology and Hepatology
• Genetics and Genomics
• Genomics and Precision Health
• Global Health
• Guide to Statistics and Methods
• Hair Disorders
• Health Care Delivery Models
• Health Care Economics, Insurance, Payment
• Health Care Quality
• Health Care Reform
• Health Care Safety
• Health Care Workforce
• Health Disparities
• Health Inequities
• Health Policy
• Health Systems Science
• History of Medicine
• Hypertension
• Images in Neurology
• Implementation Science
• Infectious Diseases
• Innovations in Health Care Delivery
• JAMA Infographic
• Law and Medicine
• Leading Change
• Less is More
• LGBTQIA Medicine
• Lifestyle Behaviors
• Medical Coding
• Medical Devices and Equipment
• Medical Education
• Medical Education and Training
• Medical Journals and Publishing
• Mobile Health and Telemedicine
• Narrative Medicine
• Neuroscience and Psychiatry
• Notable Notes
• Nutrition, Obesity, Exercise
• Obstetrics and Gynecology
• Occupational Health
• Ophthalmology
• Orthopedics
• Otolaryngology
• Pain Medicine
• Palliative Care
• Pathology and Laboratory Medicine
• Patient Care
• Patient Information
• Performance Improvement
• Performance Measures
• Perioperative Care and Consultation
• Pharmacoeconomics
• Pharmacoepidemiology
• Pharmacogenetics
• Pharmacy and Clinical Pharmacology
• Physical Medicine and Rehabilitation
• Physical Therapy
• Physician Leadership
• Population Health
• Primary Care
• Professional Well-being
• Professionalism
• Psychiatry and Behavioral Health
• Public Health
• Pulmonary Medicine
• Regulatory Agencies
• Reproductive Health
• Research, Methods, Statistics
• Resuscitation
• Rheumatology
• Risk Management
• Scientific Discovery and the Future of Medicine
• Shared Decision Making and Communication
• Sleep Medicine
• Sports Medicine
• Stem Cell Transplantation
• Substance Use and Addiction Medicine
• Surgical Innovation
• Surgical Pearls
• Teachable Moment
• Technology and Finance
• The Art of JAMA
• The Arts and Medicine
• The Rational Clinical Examination
• Tobacco and e-Cigarettes
• Translational Medicine
• Trauma and Injury
• Treatment Adherence
• Ultrasonography
• Users' Guide to the Medical Literature
• Vaccination
• Venous Thromboembolism
• Veterans Health
• Women's Health
• Workflow and Process
• Wound Care, Infection, Healing

Get the latest research based on your areas of interest.

Others also liked.

• Download PDF
• X Facebook More LinkedIn

Logue JK , Franko NM , McCulloch DJ, et al. Sequelae in Adults at 6 Months After COVID-19 Infection. JAMA Netw Open. 2021;4(2):e210830. doi:10.1001/jamanetworkopen.2021.0830

Manage citations:

© 2024

• Permissions

Sequelae in Adults at 6 Months After COVID-19 Infection

• 1 Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle
• Correction Error in Table JAMA Network Open

Many individuals experience persistent symptoms and a decline in health-related quality of life (HRQoL) after coronavirus disease 2019 (COVID-19) illness. 1 Existing studies have focused on hospitalized individuals 30 to 90 days after illness onset 2 - 4 and have reported symptoms up to 110 days after illness. 3 Longer-term sequelae in outpatients have not been well characterized.

A longitudinal prospective cohort of adults with laboratory-confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was enrolled at the University of Washington with a concurrent cohort of healthy patients in a control group (eAppendix in the Supplement ). Electronic informed consent was obtained, and the study was approved by the University of Washington human participants institutional review board. This study followed the Strengthening the Reporting of Observational Studies in Epidemiology ( STROBE ) reporting guideline. COVID-19 symptom data were obtained at the time of acute illness or retrospectively recounted at a 30-day enrollment visit. A total of 234 participants with COVID-19 were contacted between August and November 2020 to complete a single follow-up questionnaire between 3 and 9 months after illness onset. We did not perform statistical tests for this descriptive analysis because of the small numbers in each subgroup. Data analysis was conducted in R version 4.0.2 (R Project for Statistical Computing).

A total of 177 of 234 participants (75.6%; mean [range] age, 48.0 [18-94] years; 101 [57.1%] women) with COVID-19 completed the survey. Overall, 11 (6.2%) were asymptomatic, 150 (84.7%) were outpatients with mild illness, and 16 (9.0%) had moderate or severe disease requiring hospitalization ( Table ). Hypertension was the most common comorbidity (23 [13.0%]). The follow-up survey was completed a median (range) of 169 (31-300) days after illness onset among participants with COVID-19 ( Figure , A) and 87 (71-144) days after enrollment among 21 patients in the control group. Among participants with COVID-19, persistent symptoms were reported by 17 of 64 patients (26.6%) aged 18 to 39 years, 25 of 83 patients (30.1%) aged 40 to 64 years, and 13 of 30 patients (43.3%) aged 65 years and older. Overall, 49 of 150 outpatients (32.7%), 5 of 16 hospitalized patients (31.3%), and 1 of 21 healthy participants (4.8%) in the control group reported at least 1 persistent symptom. Of 31 patients with hypertension or diabetes, 11 (35.5%) experienced ongoing symptoms.

The most common persistent symptoms were fatigue (24 of 177 patients [13.6%]) and loss of sense of smell or taste (24 patients [13.6%]) ( Figure , B). Overall, 23 patients (13.0%) reported other symptoms, including brain fog (4 [2.3%]). A total of 51 outpatients and hospitalized patients (30.7%) reported worse HRQoL compared with baseline vs 4 healthy participants and asymptomatic patients (12.5%); 14 patients (7.9%) reported negative impacts on at least 1 activity of daily living (ADL), the most common being household chores.

In this cohort of individuals with COVID-19 who were followed up for as long as 9 months after illness, approximately 30% reported persistent symptoms. A unique aspect of our cohort is the high proportion of outpatients with mild disease. Persistent symptoms were reported by one-third of outpatients in our study, consistent with a previously reported study, 4 in which 36% of outpatients had not returned to baseline health by 14 to 21 days following infection. However, this has not been previously described 9 months after infection.

Consistent with existing literature, fatigue was the most commonly reported symptom. 2 - 4 This occurred in 14% of individuals in this study, lower than the 53% to 71% 2 - 4 reported in cohorts of hospitalized patients, likely reflecting the lower acuity of illness in our cohort. Furthermore, impairment in HRQoL has previously been reported among hospitalized patients who have recovered from COVID-19; we found 29% of outpatients reported worsened HRQoL. 5

Notably, 14 participants, including 9 nonhospitalized individuals, reported negative impacts on ADLs after infection. With 57.8 million cases worldwide, even a small incidence of long-term debility could have enormous health and economic consequences. 6

Study limitations include a small sample size, single study location, potential bias from self-reported symptoms during illness episode, and loss to follow-up of 57 participants. To our knowledge, this study presents the longest follow-up symptom assessment after COVID-19 infection. Our research indicates that the health consequences of COVID-19 extend far beyond acute infection, even among those who experience mild illness. Comprehensive long-term investigation will be necessary to fully understand the impact of this evolving viral pathogen.

Accepted for Publication: January 16, 2021.

Published: February 19, 2021. doi:10.1001/jamanetworkopen.2021.0830

Correction: This article was corrected on March 9, 2021, to fix an error in the Table.

Open Access: This is an open access article distributed under the terms of the CC-BY License . © 2021 Logue JK et al. JAMA Network Open .

Corresponding Author: Helen Y. Chu, MD, MPH, Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, 750 Republican St, Room E691, Seattle, WA 98109 ( [email protected] ).

Author Contributions : Ms Logue and Dr Chu had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Mr Franko and Ms Logue contributed equally to this study and are joint first authors.

Concept and design: Logue, Franko, McCulloch, Magedson, Wolf, Chu.

Acquisition, analysis, or interpretation of data: Logue, Franko, McCulloch, McDonald, Chu.

Drafting of the manuscript: Logue, Franko.

Critical revision of the manuscript for important intellectual content: All authors.

Statistical analysis: Logue, Franko.

Obtained funding: Chu.

Administrative, technical, or material support: All authors.

Supervision: Logue, McCulloch, Chu.

Conflict of Interest Disclosures: Dr Chu reported receiving personal fees from Merck, Ellume, the Bill and Melinda Gates Foundation, GlaxoSmithKline, and Pfizer; receiving grants from Sanofi-Pasteur; and receiving reagents from Cepheid Research outside the submitted work. No other disclosures were reported.

Funding/Support: This research was funded by grants from the Bill and Melinda Gates Foundation.

Role of the Funder/Sponsor: The Bill and Melinda Gates Foundation had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

• Register for email alerts with links to free full-text articles
• Access PDFs of free articles
• Manage your interests
• Save searches and receive search alerts