PhD Dissertation · Structure · DoingResearch.net

What it is

The written work at the end of a doctorate: a long report of research that makes an original contribution to knowledge. The UK’s Quality Assurance Agency (QAA) states the requirement plainly: every UK doctorate, whatever its form, must show an original contribution to knowledge, through new research or a new application of existing knowledge.

That is the step up from a master’s thesis. A master’s thesis has to add something and show it knows the literature; a dissertation has to change what the field knows, even if only a little, and the examiners have to agree that it does. Most doctoral examiners, the QAA says, are looking for work of a quality that could pass peer review in the field, even if only parts of it are published.

The names swap between countries. In most US universities this document is the dissertation and the master’s paper is the thesis. In the UK it’s usually called a thesis.

It comes in two main shapes. The traditional form is a monograph: one argument developed across chapters, like a book. The other is the thesis by publication, often called the three-paper or article-based dissertation: a set of related journal articles, framed by an introduction and a conclusion that tie them together.

Who reads it

Your committee or examiners, who are specialists and read every page. In the US that’s usually a committee led by your advisor. At the University of Rochester’s political science department, for example, the dissertation committee needs at least two political science faculty, one of them the advisor, and one from outside. In the UK the thesis goes to examiners, and at least one external examiner from another institution is required at every doctoral oral exam.

Then the field. Dissertations are deposited and indexed, and future researchers will find yours when they search your topic. Some chapters may become journal articles or a book; others will be read mainly by the few people working on the same question.

The parts

1Front matter

The title page, abstract and table of contents, plus acknowledgments and other pages your graduate school requires, all in the exact order its format manual sets. Some include a copyright page. Article-based dissertations may need a preface explaining who did what in any co-authored paper.

2Introduction

The problem, why it matters, the research questions, and a map of what follows. In an article-based dissertation it does more work: it has to show how the separate papers add up to one project.

3Literature review

The state of the field on your question, organized around debates and gaps. In a monograph this is often its own chapter. In an article-based dissertation the introduction may carry a general review, with narrower reviews inside each paper.

4Method

How the research was done, described fully enough to be checked.

5The body: chapters or papers

In a monograph, several chapters that build one argument: results and analysis, case by case or question by question. In an article-based dissertation, usually three papers (some programs allow more or fewer), each written as a journal article with its own introduction, methods, results and discussion. The papers must be related closely enough that the contribution shows across them as a body of work. If a paper is already published, you’ll need to cite the publication and may need the publisher’s permission to include it.

6Conclusion

What the whole dissertation shows, stated clearly as its contribution to knowledge, with its limits and the questions it leaves open. In an article-based dissertation, this is where you show the papers form one original contribution, not three unrelated ones.

7References and appendices

Every source cited, in your field’s style, then appendices for instruments, extra data, code and other supporting material.

What this level expects

An original contribution to knowledge, and a clear statement of what it is.
Passing a qualifying stage first. Many US programs require qualifying or comprehensive exams and a dissertation proposal or prospectus before you’re admitted to candidacy. At Rochester’s political science department, the qualifying exam combines a public presentation, a written prospectus and an oral defense, and at least seven months must pass between that and the final defense. UK programs use progress reviews instead; the first often comes at the end of the first year.
Independent work. Your advisor guides you, but the question, the design and the argument have to be yours. In article-based dissertations, programs often expect you to be first author on each paper.
A defense. In the US, a final oral exam before the committee, at some programs opening with a public talk. In the UK, the viva voce (or viva): a closed oral exam where the examiners question you on the thesis. Examiners often ask for minor or major corrections, or for resubmission, before the degree is awarded.
Deposit. After approval, the dissertation goes into the university’s repository and, at many US universities, to ProQuest.

Common mistakes

A question too big for one project. A dissertation has to be finished, not just started well. Umberto Eco’s advice in How to Write a Thesis applies here: choose sources you can reach and methods you can handle, and treat your outline as a hypothesis to revise.
Assuming the contribution is obvious. Say what’s new, plainly, in the introduction and again in the conclusion. Examiners shouldn’t have to infer it.
Three papers with no thread. An article-based dissertation needs papers that answer parts of one question. Decide on the format early with your advisor, not after the papers are written.
Losing touch with the committee. Meet regularly and share drafts. A committee that sees the work only at the end may ask for changes you could have made a year earlier.
Ignoring copyright and co-authorship rules for published papers until deposit day.
Choosing an embargo in a hurry. If you plan a book or patent, decide whether to delay public release before you submit. Embargo options and limits are set by your university.

What varies

Length depends on field. The QAA notes that a mathematics thesis may be relatively short because its core is a proof, while one in a discursive subject may run to 100,000 words, and that neither signals a different level of achievement. The monograph is the traditional form; the QAA notes that doctorates by publication are offered particularly in science and engineering. Defense formats differ too: the UK viva is usually closed, while some European countries hold a public defense. Deposit rules are changing. The Library of Congress notes that US universities increasingly don’t require deposit with ProQuest, and put a copy in their own repository instead, often after an embargo. Your graduate school’s format manual and your department’s handbook are the rules that apply to you.