Direct comparison
Thesis vs Dissertation: What's the Difference? | CASRAI
In the US, a thesis is master's level and a dissertation is doctoral; in the UK and Australia, the terms are often reversed. Both require original scholarly work.
Side-by-side comparison
| Dimension | US Thesis (Master's) | US Dissertation (Doctoral) | UK / Australia Usage |
|---|---|---|---|
| Degree level | Master's degree | Doctoral (PhD) degree | Terms often reversed: thesis = doctoral; dissertation = master's |
| Original research required | May synthesise existing research; original research varies by programme | Must make an original, significant contribution to knowledge | Doctoral thesis must demonstrate original contribution |
| Typical length | 40–80 pages (approx. 15,000–30,000 words) | 200–400 pages (approx. 80,000–100,000 words) | Doctoral thesis: 70,000–100,000 words; master's dissertation: 15,000–25,000 words |
| Defence format | Committee review; may include oral presentation | Public oral defence (viva voce) before a committee | Doctoral viva voce: oral examination by internal and external examiners |
| Committee size | Typically 3 members | Typically 3–5 members plus external examiner | Usually 2 examiners (1 internal, 1 external) at the viva |
| Supervision | Faculty supervisor / advisor | Primary supervisor (advisor) with advisory committee | Primary supervisor plus secondary/co-supervisor |
| Submission process | Submitted to graduate school; may be deposited in ProQuest ETD | Submitted to graduate school; ProQuest ETD deposit; open-access options | Submitted to institution; often deposited in institutional repository (EThOS in UK) |
Common questions
FAQ
Why are thesis and dissertation sometimes used interchangeably?+
Because the terminology is genuinely different across countries. In the United States, "dissertation" typically means a doctoral work and "thesis" means a master's work. In the United Kingdom, Australia, and many European countries, "thesis" refers to the doctoral document and "dissertation" to the master's work. This transatlantic reversal causes widespread confusion.
Does a US master's thesis require original research?+
It depends on the programme and institution. Some master's programmes require an original research thesis; others offer a non-thesis track with a capstone project or coursework only. In contrast, a doctoral dissertation invariably requires an original, significant contribution to the field, evidenced through the research and demonstrated in a formal defence.
What is a viva voce?+
A viva voce (Latin for "by live voice") is an oral examination in which the candidate defends their doctoral thesis in front of examiners. In the UK and Australia, it is the primary mechanism for assessing whether the thesis demonstrates an original contribution to knowledge. In the US system, the oral defence of a dissertation serves a similar function, though the format varies by institution and discipline.
Going deeper
