Thesis vs. Dissertation: What’s the difference?

A thesis and a dissertation are both extensive research papers, and both require literature searches and novel findings, but the two differ in various ways. Their definitions also differ across regions. Typically, in North America, a thesis is required for the completion of a master’s degree, while a dissertation is required for the completion of a doctoral degree. The former is long, while the latter is longer and more intensive.

Despite these differences, the two terms are often used interchangeably, especially among those who haven’t completed one or the other. Here, we’ll compare the components, length, and purpose of these two academic documents to clearly understand the differences between these important papers in the life of a graduate student.

What’s a thesis?

The term “thesis” explained here is generally consistent with how the word is used in North America to describe this substantive research paper.

Definition

A thesis is an extended argument (PDF). It is a research-based document that displays the student’s/author’s knowledge and understanding of a specific subject within their field of study. It generally presents findings on a particular topic. 

See this and this (PDFs) for examples. These superb master’s theses from Canada will give you an idea of the size and format of these papers.

Who would write a thesis?

You generally write a thesis if you’re undertaking a research-oriented master's degree program (as opposed to a practical program, which may require a capstone, internship, exam, etc.). 

The thesis is the essential part of a program’s research component, demonstrating the student's ability to critically analyze the literature and complete independent research. The process of writing a thesis involves exploring a specific research question, conducting a comprehensive literature review, collecting and analyzing data, and presenting findings in a structured and cohesive way.

A thesis' specific requirements and expectations differ depending on the academic institution, department, and program.

Components of a thesis

A thesis is typically presented in chapters. How many chapters will vary, but a common structure is:

• Introduction: Presents the research topic, purpose, and objectives, setting the context for the work.
• Literature review: Comprehensive survey of existing scholarly material related to the research topic, highlighting key theories and findings.
• Methodology: Describes the methods, procedures, and tools used in doing the research.
• Research: The actual performing of the study, collecting, and analyzing data relevant to the research question.
• Findings and conclusions: Gives the results obtained and explains their significance in relation to the research question.
• Limitations and future research: Outlines the study’s shortcomings and suggests potential areas for future investigation.

Within that structure, and in addition to those parts, a thesis may also include: 

• Cover page: Contains the thesis title, author's name, institution, department, date, and other relevant information
• Abstract: A brief summary of the thesis, highlighting the research objectives, methods, key findings, and conclusions.
• Certificates of own work
• Certificate of readiness to be included in the library
• Certificate that the research has not been presented to another university
• Acknowledgments
• Dedication
• Table of contents: List of the main sections, subsections, and corresponding page numbers.
• Index of figures and tables
• References: A comprehensive list of all the sources cited in the thesis, following a specific citation style (e.g., APA, MLA).
• Appendices (optional): Additional materials include:

1. Glossary
2. Abbreviations and/or acronyms used
3. Questionnaire or interview schedule/s (if used)
4. Data acquired in the form of transcripts or numeric tables
5. Research protocol
6. Ethics protocol

What’s a dissertation?

This is also viewed from a North American perspective, where a dissertation is usually the main research work toward completing a research-based doctoral program.

Definition

A dissertation is a comprehensive and in-depth research project completed as part of the requirements for a doctoral degree. It’s a substantial piece of original work that contributes new knowledge to a specific field of study.  Naturally, when it’s completed as the major requirement for earning a PhD, it’s longer, more detailed, and the expectations are higher.

Dissertations themselves can add to the literature in the field. For this reason, some students choose to publish them and have them indexed. The research and the data acquired while working on a dissertation can potentially lead to more publications and help define the researcher’s growing area of expertise.

See this and this (PDFs)  top-ranking dissertation on ProQuest for good examples.

Who would write a dissertation?

Completion and defense of a dissertation is a standard requirement for doctoral students to earn a PhD or another doctorate such as an EdD or DM. But some specialized degrees, such as a PsyD (Doctor of Psychology), JD (Juris Doctor) or DPT (Doctor of Physical Therapy) may have practice-based requirements in place of a research project, as these courses of study are geared more toward practical application.

Components of a dissertation

A dissertation’s components are generally the same as those of a thesis. You can look at the list above for a thesis to see what typically goes into a dissertation. But, if compared with a master’s thesis, most aspects are longer and more rigorous.

Length

The word count requirements for theses can vary significantly, but doctoral dissertations often range 40,000–80,000 words or, per Harvard, 100–300 pages.

Differences between a thesis and a dissertation

As already touched on, the key differences are in where the two documents are used, length, and rigor. There are also regional differences.

Purpose

A thesis typically demonstrates a master’s degree program student's grasp and presentation of a specific subject in their field of study. It normally involves a literature review, data analysis, and original research, but it is usually shorter and less comprehensive than a dissertation. The standards for rigor and novelty may also be lower.

A dissertation requires more extensive research, original contributions to the field, and a deeper exploration of the research topic. A dissertation is typically the output associated with a doctoral degree program.

Structure

The main differences in structure between a thesis and a dissertation are in the scope and complexity.

Length

The word count requirement for theses and dissertations can vary depending on the institution and program.

A thesis is usually 20,000–40,000 words. However, there have been cases of mathematics dissertations that were only a few pages long!

Doctoral dissertations may range 60,000 to upward of 100,000 words, and exceed 100 pages. Many universities, however, seek around 80,000 words.

Oversight and process

A thesis may simply be submitted to the student's instructor, though rigorous thesis programs require a committee and defense. A dissertation will nearly always require the student to choose a chair, a committee, and then go through a more rigorous defense and revision (if necessary).

• Committee: Master's thesis committees usually have fewer members (typically 2–3) than doctoral dissertation committees (often 4–5, or even more).
• Guidance: Master's students often receive more detailed direction from advisers than doctoral students, who are expected to work more independently.
• Review: Dissertation reviews are typically more rigorous, often involving external reviewers, while thesis reviews are usually internal.
• Defense: A dissertation defense is generally more intense and formal, as it often involves a presentation to the wider academic community, while a thesis defense might be more confined and informal.
• Revision: The revision process for a doctoral dissertation is typically more extensive, given the larger scope of the project and higher stakes involved, compared with those for a master's thesis.

Regional differences

The terms' use varies among (and even within) countries. Here are some general regional differences:

In the United Kingdom, a thesis is commonly associated with both master's and doctoral degree programs. For example, the University College London refers to a thesis for EngD, MPhil, MD(Res), and PhD degrees. At the University of Nottingham, a dissertation is written for a research master’s degree.

In Australia and New Zealand, “thesis” is generally used to refer to a substantial research project completed for a higher degree, though not limited to a master’s (you’ll find ample references to a “PhD thesis”).

In Latin American countries,  the thesis is commonly used to refer to both master's and doctoral research projects.

Closing thoughts

Both theses and dissertations are necessary documents for students in graduate programs. Despite the differences in expectations, and even in definitions of these papers, the student-author must do a diligent and rigorous job to earn their degree.

Here are a few helpful resources if you want to get into greater detail:

• Writing the Winning Thesis or Dissertation: A Step-By-Step Guide
• 100 PhD rules of the game to successfully complete a doctoral dissertation (PDF)
• Theses and Dissertations: A Guide to Writing in Social and Physical Sciences

Perfect the English on your thesis or dissertation

Whether you’re submitting a thesis or a dissertation, if it’s in English, it should:

• Have no grammatical or spelling mistakes
• Use field-appropriate language
• Concisely and clearly communicate your research.

That’s what AJE expert editors will do for you. Within days, you can receive an expert English edit of your work. The editor will be familiar with your field of study and will comprehensively improve both the language quality and the delivery of your message. Look into AJE English Editing.