what does a dissertation require

What is a Ph.D. Dissertation?

[I wrote this in 1993 as a letter to a student concerning a draft of his dissertation. In 2003 I edited it to remove some specific references to the student and present it as a small increment to the information available to my grad students. In 2023 I made small edits for grammar and to expand coverage.--spaf]

Let me start by reviewing some things that may seem obvious:

• Your dissertation is part of the requirements for a PhD. The research, theory, experimentation, et al. also contribute. One does not attempt to capture everything in one's dissertation.
• The dissertation is a technical work that documents and proves one's thesis. It is intended for a technical audience and must be clear and complete but not necessarily exhaustively comprehensive. Also note -- experimental data, if used, is not the proof -- it is evidence. The proof is presented as an analysis and critical presentation. Generally, every statement in your dissertation must be common knowledge, supported by citation to technical literature, or original results proved by the candidate (you). Each of those statements must directly relate to the proof of the thesis, or else they are unnecessary.

Let's revisit the idea of the thesis itself. It is a hypothesis, a conjecture, or a theorem. The dissertation is a formal, stylized document used to argue your thesis. The thesis must be significant, original (no one has yet demonstrated it to be true), and it must extend the state of scientific knowledge.

The first thing you need to do is to come up with no more than three sentences that express your thesis. Your committee must agree that your statements form a valid thesis statement. You, too, must be happy with the statement -- it should be what you will tell anyone if they ask you what your thesis is (few people will want to hear an hour's presentation as a response).

Once you have a thesis statement, you can begin developing the dissertation. The abstract, for instance, should be a one-page description of your thesis and how you present the proof of it. The abstract should summarize the results of the thesis and should stress the contributions to science made thereby.

Perhaps the best way to understand how an abstract should look would be to examine the abstracts of several dozen dissertations that have already been accepted. Our university library has a collection of them. This is a good approach to see how an entire dissertation is structured and presented. MIT Press has published the ACM doctoral dissertation award series for decades, so you may find some of those to be good examples to read -- they should be in any large technical library.

The dissertation itself should be structured into 4 to 6 chapters. The following is one commonly-used structure:

• Introduction. Provide an introduction to the basic terminology, cite appropriate background work, and briefly discuss related work that has already covered aspects of the problem.
• Abstract model. Discuss an abstract model of what you are trying to prove. This chapter should not discuss any specific implementation (see below)
• Validation of model/proof of theorems. This is a chapter showing proof of the model. It could be a set of proofs or a discussion of the construction and validation of a model or simulation to gather supporting data.
• Measurements/data. This would present data collected from actual use, simulations, or other sources. The presentation would include analysis to show support for the underlying thesis.
• Additional results. In some work, there may be secondary confirmation studies, or it might be the case that additional significant results are collected along the way to the proof of the central thesis. These would be presented here.
• Conclusions and future work. This is where the results are all tied together and presented. Limitations, restrictions, and special cases should be clearly stated here, along with the results. Some extensions as future work may also be described.

Let's look at these in a little more detail

Chapter I, Introduction. Here, you should clearly state the thesis and its importance. This is also where you define terms and other concepts used elsewhere. There is no need to write 80 pages of background on your topic here. Instead, you can cover almost everything by saying: "The terminology used in this work matches the definitions given in [citation, citation] unless noted otherwise." Then, cite some appropriate works that give the definitions you need. The progress of science is that we learn and use the work of others (with appropriate credit). Assume you have a technically literate readership familiar with (or able to find) standard references. Do not reference popular literature or WWW sites if you can help it (this is a matter of style more than anything else -- you want to cite articles in refereed conferences and journals, if possible, or in other theses).

Also, in the introduction, you want to survey any related work that attempted something similar to your own or has a significant supporting role in your research. This should refer only to published references. You cite the work in the references, not the researchers themselves. E.g., "The experiments described in [citation] explored the foo and bar conditions, but did not discuss the further problem of baz, the central point of this work." You should not make references such as this: "Curly, Moe, and Larry all believed the same in their research [CML53]" because you do not know what they believed or thought -- you only know what the paper states. Every factual statement you make must have a specific citation tied to it in this chapter, or else it must be common knowledge (don't rely on this too much).

Chapter II. Abstract Model. Your results are to be of lasting value. Thus, the model you develop and write about (and indeed, that you defend) should have lasting value. Thus, you should discuss a model not based on Windows, Linux, Ethernet, PCMIA, or any other technology. It should be generic and capture all the details necessary to overlay the model on likely environments. You should discuss the problems, parameters, requirements, necessary and sufficient conditions, and other factors here. Consider that 20 years ago (ca 1980), the common platform was a Vax computer running VMS or a PDP-11 running Unix version 6, yet well-crafted theses of the time are still valuable today. Will your dissertation be valuable 20+ years from now (ca 2050), or have you referred to technologies that will be of only historical interest?

This model is tough to construct but is the heart of the scientific part of your work. This is the lasting part of the contribution, and this is what someone might cite 50 years from now when we are all using MS Linux XXXXP on computers embedded in our wrists with subspace network links!

Chapters III & IV, Proof.There are basically three proof techniques that I have seen used in a computing dissertation, depending on the thesis topic. The first is analytic, where one takes the model or formulae and shows, using formal manipulations, that the model is sound and complete. A second proof method is stochastic, using statistical methods and measurements to show that something is true in the anticipated cases.

• clearly showing how your implementation model matches the conditions of your abstract model,
• describing all the variables and why you set them as you do,
• accounting for confounding factors, and
• showing the results.

Chapter V. Additional results. This may be folded into Chapter III in some theses or multiple chapters in a thesis with many parts (as in a theory-based thesis). This may be where you discuss the effects of technology change on your results. This is also a place where you may wish to point out significant results that you obtained while seeking to prove your central thesis but which are not supportive of the thesis. Often, such additional results are published in a separate paper.

Chapter VI. Conclusions and Future Work. This is where you discuss what you found from your work, incidental ideas and results that were not central to your thesis but of value nonetheless (if you did not have them in Chapter V), and other results. This chapter should summarize all the important results of the dissertation --- note that this is the only chapter many people will ever read, so it should convey all the important results.

This is also where you should outline some possible future work that can be done in the area. What are some open problems? What are some new problems? What are some significant variations open to future inquiry?

Appendices usually are present to hold mundane details that are not published elsewhere but are critical to the development of your dissertation. This includes tables of measurement results, configuration details of experimental testbeds, limited source code listings of critical routines or algorithms, etc. It is not appropriate to include lists of readings by topic, lists of commercial systems, or other material that does not directly support the proof of your thesis.

Here are some more general hints to keep in mind as you write/edit:

• Adverbs should generally not be used -- instead, use something precise. For example, do not say that something "happens quickly." How fast is quickly? Is it relative to CPU speeds? Network speeds? Does it depend on connectivity, configuration, programming language, OS release, etc? What is the standard deviation?
• As per the above, the use of the words "fast," "slow," "perfect," "soon," "ideal," "lots of," and related should all be avoided. So should "clearly," "obviously," "simple," "like," "few," "most," "large," et al.
• What you are writing is scientific fact. Judgments of aesthetics, ethics, personal preference, and the like should be in the conclusions chapter, if they should be anywhere at all. With that in mind, avoid the use of words such as "good," "bad," "best," and any similar discussion. Also, avoid stating "In fact," "Actually," "In reality," and any similar construct -- everything you are writing must be factual, so there is no need to state such things. If you feel compelled to use one of these constructs, then carefully evaluate what you are saying to ensure you are not injecting relative terms, opinions, value judgments, or other items inappropriate for a dissertation.
• Computers and networks do not have knees, so poor performance cannot bring them to something they do not have. They also don't have hands, so "On the one hand..." is not good usage. Programs don't perform conscious thought (nor do their underlying computers), so your system does not "think" that it has seen a particular type of traffic. Generalizing from this, do not anthropomorphize your IT components!
• Avoid mention of time and environment. "Today's computers" are antiques far sooner than you think. Your thesis should still be true many years from now. If a particular time or interval is necessary, be explicit, as in "Between 1905 and 1920" rather than "Over the last 15 years." (See the difference, given some distance in time?)
• Be sure that any scientist or mathematician would recognize something you claim as proof.
• Focus on the results and not the methodology. The methodology should be clearly described but not the central topic of your discussion in chapters III & IV
• Keep concepts and instances separate. An algorithm is not the same as a program that implements it. A protocol is not the same as the realization of it; a reference model is not the same as a working example, and so on.

As a rule of thumb, a CS dissertation should probably be longer than 100 pages but less than 160. Anything outside that range should be carefully examined with the above points in mind.

Keep in mind that you -- the Ph.D. candidate -- are expected to become the world's foremost expert on your topic area. That topic area should not be unduly broad but must be big enough to be meaningful. Your advisor and committee members are not supposed to know more about the topic than you do -- not individually, at least. Your dissertation is supposed to explain your findings and, along with the defense, demonstrate your mastery of the area in which you are now the leading expert. That does not mean writing everything you know -- it means writing enough about the most important points that others can agree with your conclusions.

Last of all, don't fall into the trap that ties up many candidates and causes some of them to flame out before completion: your thesis does not need to be revolutionary. It simply needs to be an incremental advancement in the field. Few Ph.D. dissertations have ever had a marked impact on the field. Instead, it is the author's set of publications and products of the author that may change the field.

If your dissertation is like most, it will only be read by your committee and some other Ph.D. candidates seeking to build on your work. As such, it does not need to be a masterwork of literature, nor does it need to solve a long-standing problem in computing. It merely needs to be correct, to be significant in the judgment of your committee, and it needs to be complete. We will all applaud when you change the world after graduation. And at that, you will find that many well-known scientists in CS have made their careers in areas different from their dissertation topic. The dissertation is proof that you can find and present original results; your career and life after graduation will demonstrate the other concerns you might have about making an impact.

So get to work!

Have a language expert improve your writing

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

• Knowledge Base
• Dissertation

What Is a Dissertation? | Guide, Examples, & Template

A dissertation is a long-form piece of academic writing based on original research conducted by you. It is usually submitted as the final step in order to finish a PhD program.

Your dissertation is probably the longest piece of writing you’ve ever completed. It requires solid research, writing, and analysis skills, and it can be intimidating to know where to begin.

Your department likely has guidelines related to how your dissertation should be structured. When in doubt, consult with your supervisor.

You can also download our full dissertation template in the format of your choice below. The template includes a ready-made table of contents with notes on what to include in each chapter, easily adaptable to your department’s requirements.

Download Word template Download Google Docs template

• In the US, a dissertation generally refers to the collection of research you conducted to obtain a PhD.
• In other countries (such as the UK), a dissertation often refers to the research you conduct to obtain your bachelor’s or master’s degree.

Instantly correct all language mistakes in your text

Upload your document to correct all your mistakes in minutes

Table of contents

Dissertation committee and prospectus process, how to write and structure a dissertation, acknowledgements or preface, list of figures and tables, list of abbreviations, introduction, literature review, methodology, reference list, proofreading and editing, defending your dissertation, free checklist and lecture slides.

When you’ve finished your coursework, as well as any comprehensive exams or other requirements, you advance to “ABD” (All But Dissertation) status. This means you’ve completed everything except your dissertation.

Prior to starting to write, you must form your committee and write your prospectus or proposal . Your committee comprises your adviser and a few other faculty members. They can be from your own department, or, if your work is more interdisciplinary, from other departments. Your committee will guide you through the dissertation process, and ultimately decide whether you pass your dissertation defense and receive your PhD.

Your prospectus is a formal document presented to your committee, usually orally in a defense, outlining your research aims and objectives and showing why your topic is relevant . After passing your prospectus defense, you’re ready to start your research and writing.

Prevent plagiarism. Run a free check.

The structure of your dissertation depends on a variety of factors, such as your discipline, topic, and approach. Dissertations in the humanities are often structured more like a long essay , building an overall argument to support a central thesis , with chapters organized around different themes or case studies.

However, hard science and social science dissertations typically include a review of existing works, a methodology section, an analysis of your original research, and a presentation of your results , presented in different chapters.

Dissertation examples

We’ve compiled a list of dissertation examples to help you get started.

• Example dissertation #1: Heat, Wildfire and Energy Demand: An Examination of Residential Buildings and Community Equity (a dissertation by C. A. Antonopoulos about the impact of extreme heat and wildfire on residential buildings and occupant exposure risks).
• Example dissertation #2: Exploring Income Volatility and Financial Health Among Middle-Income Households (a dissertation by M. Addo about income volatility and declining economic security among middle-income households).
• Example dissertation #3: The Use of Mindfulness Meditation to Increase the Efficacy of Mirror Visual Feedback for Reducing Phantom Limb Pain in Amputees (a dissertation by N. S. Mills about the effect of mindfulness-based interventions on the relationship between mirror visual feedback and the pain level in amputees with phantom limb pain).

The very first page of your document contains your dissertation title, your name, department, institution, degree program, and submission date. Sometimes it also includes your student number, your supervisor’s name, and the university’s logo.

Read more about title pages

The acknowledgements section is usually optional and gives space for you to thank everyone who helped you in writing your dissertation. This might include your supervisors, participants in your research, and friends or family who supported you. In some cases, your acknowledgements are part of a preface.

Read more about acknowledgements Read more about prefaces

Here's why students love Scribbr's proofreading services

Discover proofreading & editing

The abstract is a short summary of your dissertation, usually about 150 to 300 words long. Though this may seem very short, it’s one of the most important parts of your dissertation, because it introduces your work to your audience.

Your abstract should:

• State your main topic and the aims of your research
• Describe your methods
• Summarize your main results
• State your conclusions

Read more about abstracts

The table of contents lists all of your chapters, along with corresponding subheadings and page numbers. This gives your reader an overview of your structure and helps them easily navigate your document.

Remember to include all main parts of your dissertation in your table of contents, even the appendices. It’s easy to generate a table automatically in Word if you used heading styles. Generally speaking, you only include level 2 and level 3 headings, not every subheading you included in your finished work.

Read more about tables of contents

While not usually mandatory, it’s nice to include a list of figures and tables to help guide your reader if you have used a lot of these in your dissertation. It’s easy to generate one of these in Word using the Insert Caption feature.

Read more about lists of figures and tables

Similarly, if you have used a lot of abbreviations (especially industry-specific ones) in your dissertation, you can include them in an alphabetized list of abbreviations so that the reader can easily look up their meanings.

Read more about lists of abbreviations

In addition to the list of abbreviations, if you find yourself using a lot of highly specialized terms that you worry will not be familiar to your reader, consider including a glossary. Here, alphabetize the terms and include a brief description or definition.

Read more about glossaries

The introduction serves to set up your dissertation’s topic, purpose, and relevance. It tells the reader what to expect in the rest of your dissertation. The introduction should:

• Establish your research topic , giving the background information needed to contextualize your work
• Narrow down the focus and define the scope of your research
• Discuss the state of existing research on the topic, showing your work’s relevance to a broader problem or debate
• Clearly state your research questions and objectives
• Outline the flow of the rest of your work

Everything in the introduction should be clear, engaging, and relevant. By the end, the reader should understand the what, why, and how of your research.

Read more about introductions

A formative part of your research is your literature review . This helps you gain a thorough understanding of the academic work that already exists on your topic.

Literature reviews encompass:

• Finding relevant sources (e.g., books and journal articles)
• Assessing the credibility of your sources
• Critically analyzing and evaluating each source
• Drawing connections between them (e.g., themes, patterns, conflicts, or gaps) to strengthen your overall point

A literature review is not merely a summary of existing sources. Your literature review should have a coherent structure and argument that leads to a clear justification for your own research. It may aim to:

• Address a gap in the literature or build on existing knowledge
• Take a new theoretical or methodological approach to your topic
• Propose a solution to an unresolved problem or advance one side of a theoretical debate

Read more about literature reviews

Theoretical framework

Your literature review can often form the basis for your theoretical framework. Here, you define and analyze the key theories, concepts, and models that frame your research.

Read more about theoretical frameworks

Your methodology chapter describes how you conducted your research, allowing your reader to critically assess its credibility. Your methodology section should accurately report what you did, as well as convince your reader that this was the best way to answer your research question.

A methodology section should generally include:

• The overall research approach ( quantitative vs. qualitative ) and research methods (e.g., a longitudinal study )
• Your data collection methods (e.g., interviews or a controlled experiment )
• Details of where, when, and with whom the research took place
• Any tools and materials you used (e.g., computer programs, lab equipment)
• Your data analysis methods (e.g., statistical analysis , discourse analysis )
• An evaluation or justification of your methods

Read more about methodology sections

Your results section should highlight what your methodology discovered. You can structure this section around sub-questions, hypotheses , or themes, but avoid including any subjective or speculative interpretation here.

Your results section should:

• Concisely state each relevant result together with relevant descriptive statistics (e.g., mean , standard deviation ) and inferential statistics (e.g., test statistics , p values )
• Briefly state how the result relates to the question or whether the hypothesis was supported
• Report all results that are relevant to your research questions , including any that did not meet your expectations.

Additional data (including raw numbers, full questionnaires, or interview transcripts) can be included as an appendix. You can include tables and figures, but only if they help the reader better understand your results. Read more about results sections

Your discussion section is your opportunity to explore the meaning and implications of your results in relation to your research question. Here, interpret your results in detail, discussing whether they met your expectations and how well they fit with the framework that you built in earlier chapters. Refer back to relevant source material to show how your results fit within existing research in your field.

Some guiding questions include:

• What do your results mean?
• Why do your results matter?
• What limitations do the results have?

If any of the results were unexpected, offer explanations for why this might be. It’s a good idea to consider alternative interpretations of your data.

Read more about discussion sections

Your dissertation’s conclusion should concisely answer your main research question, leaving your reader with a clear understanding of your central argument and emphasizing what your research has contributed to the field.

In some disciplines, the conclusion is just a short section preceding the discussion section, but in other contexts, it is the final chapter of your work. Here, you wrap up your dissertation with a final reflection on what you found, with recommendations for future research and concluding remarks.

It’s important to leave the reader with a clear impression of why your research matters. What have you added to what was already known? Why is your research necessary for the future of your field?

Read more about conclusions

It is crucial to include a reference list or list of works cited with the full details of all the sources that you used, in order to avoid plagiarism. Be sure to choose one citation style and follow it consistently throughout your dissertation. Each style has strict and specific formatting requirements.

Common styles include MLA , Chicago , and APA , but which style you use is often set by your department or your field.

Create APA citations Create MLA citations

Your dissertation should contain only essential information that directly contributes to answering your research question. Documents such as interview transcripts or survey questions can be added as appendices, rather than adding them to the main body.

Read more about appendices

Making sure that all of your sections are in the right place is only the first step to a well-written dissertation. Don’t forget to leave plenty of time for editing and proofreading, as grammar mistakes and sloppy spelling errors can really negatively impact your work.

Dissertations can take up to five years to write, so you will definitely want to make sure that everything is perfect before submitting. You may want to consider using a professional dissertation editing service , AI proofreader or grammar checker to make sure your final project is perfect prior to submitting.

After your written dissertation is approved, your committee will schedule a defense. Similarly to defending your prospectus, dissertation defenses are oral presentations of your work. You’ll present your dissertation, and your committee will ask you questions. Many departments allow family members, friends, and other people who are interested to join as well.

After your defense, your committee will meet, and then inform you whether you have passed. Keep in mind that defenses are usually just a formality; most committees will have resolved any serious issues with your work with you far prior to your defense, giving you ample time to fix any problems.

As you write your dissertation, you can use this simple checklist to make sure you’ve included all the essentials.

Checklist: Dissertation

My title page includes all information required by my university.

I have included acknowledgements thanking those who helped me.

My abstract provides a concise summary of the dissertation, giving the reader a clear idea of my key results or arguments.

I have created a table of contents to help the reader navigate my dissertation. It includes all chapter titles, but excludes the title page, acknowledgements, and abstract.

My introduction leads into my topic in an engaging way and shows the relevance of my research.

My introduction clearly defines the focus of my research, stating my research questions and research objectives .

My introduction includes an overview of the dissertation’s structure (reading guide).

I have conducted a literature review in which I (1) critically engage with sources, evaluating the strengths and weaknesses of existing research, (2) discuss patterns, themes, and debates in the literature, and (3) address a gap or show how my research contributes to existing research.

I have clearly outlined the theoretical framework of my research, explaining the theories and models that support my approach.

I have thoroughly described my methodology , explaining how I collected data and analyzed data.

I have concisely and objectively reported all relevant results .

I have (1) evaluated and interpreted the meaning of the results and (2) acknowledged any important limitations of the results in my discussion .

I have clearly stated the answer to my main research question in the conclusion .

I have clearly explained the implications of my conclusion, emphasizing what new insight my research has contributed.

I have provided relevant recommendations for further research or practice.

If relevant, I have included appendices with supplemental information.

I have included an in-text citation every time I use words, ideas, or information from a source.

I have listed every source in a reference list at the end of my dissertation.

I have consistently followed the rules of my chosen citation style .

I have followed all formatting guidelines provided by my university.

Congratulations!

The end is in sight—your dissertation is nearly ready to submit! Make sure it's perfectly polished with the help of a Scribbr editor.

If you’re an educator, feel free to download and adapt these slides to teach your students about structuring a dissertation.

Open Google Slides Download PowerPoint

Is this article helpful?

Other students also liked.

• How to Write a Literature Review | Guide, Examples, & Templates
• Dissertation Table of Contents in Word | Instructions & Examples
• How to Choose a Dissertation Topic | 8 Steps to Follow

More interesting articles

• Checklist: Writing a dissertation
• Dissertation & Thesis Outline | Example & Free Templates
• Dissertation Binding and Printing | Options, Tips, & Comparison
• Example of a dissertation abstract
• Figure and Table Lists | Word Instructions, Template & Examples
• How to Write a Discussion Section | Tips & Examples
• How to Write a Dissertation or Thesis Proposal
• How to Write a Results Section | Tips & Examples
• How to Write a Thesis or Dissertation Conclusion
• How to Write a Thesis or Dissertation Introduction
• How to Write an Abstract | Steps & Examples
• How to Write Recommendations in Research | Examples & Tips
• List of Abbreviations | Example, Template & Best Practices
• Operationalization | A Guide with Examples, Pros & Cons
• Prize-Winning Thesis and Dissertation Examples
• Purpose and structure of an advisory report
• Relevance of Your Dissertation Topic | Criteria & Tips
• Research Paper Appendix | Example & Templates
• Shorten your abstract or summary
• Theoretical Framework Example for a Thesis or Dissertation
• Thesis & Dissertation Acknowledgements | Tips & Examples
• Thesis & Dissertation Database Examples
• Thesis & Dissertation Title Page | Free Templates & Examples
• What is a Dissertation Preface? | Definition & Examples
• What is a Glossary? | Definition, Templates, & Examples
• What Is a Research Methodology? | Steps & Tips
• What Is a Theoretical Framework? | Guide to Organizing
• What Is a Thesis? | Ultimate Guide & Examples

What is your plagiarism score?