Dissertation vs. Thesis—What’s the Difference? (2024)

If you’re confused about the meaning of dissertation versus thesis, you’re not alone. These two types of academic writing have a lot in common, but their meanings are reversed in American and British English. Depending on where you are in the world, the differences between a dissertation and a thesis might change!

What is a dissertation vs. a thesis?

In American English, a dissertation is a research paper that’s required to earn a doctorate degree, while a thesis is a research paper required to earn a master’s degree. Dissertations and theses (the plural of thesis) are often mixed up because they’re both lengthy research papers written for higher education, especially as part of a master’s or doctorate program. A thesis or dissertation is often a requirement for obtaining an academic degree, and both are usually seen as a gatekeeper for becoming eligible to graduate.

Informally the words dissertation and thesis are often used interchangeably, which only adds to the confusion. However, in the formal academic world, their meanings are different, although some universities occasionally have their own unique definitions. Let’s take a look at what dissertation and thesis actually mean.

What is a dissertation?

In American English, a dissertation is a highly involved research paper written as a requirement to earn a doctorate degree. When we say “highly involved,” we mean it; dissertations run 300 pages or more, essentially becoming a book-length research paper.

The central attribute of a dissertation is original research: To earn a doctorate, a person must submit new discoveries and data to their chosen field. This is symbolic of becoming part of a body of academic knowledge, and a systemic way to encourage the advancement of science.

In scientific fields of study, dissertations are empirical, drawing on data collected by the writer. In less-scientific fields, like literature or philosophy, dissertations are nonempirical: Instead of new data, “original research” is replaced by innovative new ideas, interpretations, analyses, or perspectives.

Dissertation may also involve what’s known as a dissertation defense, an oral presentation in front of a panel of experts, in addition to the paper. In a dissertation defense, the experts ask questions about the findings to test their validity, and the student must “defend” their research by explaining their methods and reasoning. The panel then decides whether or not the student graduates and earns their degree.

What is a thesis?

In American English, a thesis paper is a lengthy research paper written as a requirement to earn a master’s degree (or sometimes a bachelor’s degree, depending on the university). Also referred to as a “senior thesis” for undergraduate courses, these papers are written at the end of a program as a culmination of their studies, similar to dissertations.

Unlike a dissertation, a thesis doesn’t necessarily involve original research or ideas, although many master’s theses do. Generally, a thesis is less about adding to a body of knowledge, and more about testing a student’s skills in research, comprehension, or analysis. Regardless, a thesis paper is still a considerable amount of work and requires more effort than a standard academic paper.

Dissertation vs. thesis in American and British English

We’ve talked before about how British English and American English are different, and the definitions of dissertation versus thesis are just another example.

In short, the meanings are reversed: In British English, the term dissertation is used for bachelor’s and master’s programs, whereas thesis is used for doctorates. Keep in mind that academic institutions are very different in the US and the UK, not to mention in each individual English-speaking country, so what’s involved in a bachelor’s, master’s, and doctorate program is also different.

Do you need to write a thesis or dissertation?

It’s important to remember that the words dissertation and thesis are frequently used interchangeably, so the technical definitions are just for formal situations—like when submitting one or the other. If you’re confused, you can also ask your adviser. Each school or institution may have their own definitions of the terms.

Dissertation vs. thesis FAQ

What is a dissertation versus a thesis?

Dissertations and theses (the plural of thesis) are often confused because they’re both lengthy research papers written for higher education. In American English, a dissertation is written to earn a doctorate whereas a thesis is written to earn a master’s (or sometimes a bachelor’s). In many informal situations, however, the terms dissertation and thesis are used interchangeably.

How do American and British English define dissertation versus thesis?

In British English, the meanings of dissertation and thesis are reversed: A thesis is written to earn a doctorate, and a dissertation is written to earn a master’s or bachelor’s. Keep in mind that academic institutions are very different in the US and the UK, not to mention in each individual English-speaking country, so what’s involved in a bachelor’s, master’s, and doctorate program is also different.

When to use thesis or dissertation?

It’s important to remember that the words dissertation and thesis are frequently used interchangeably, so the technical definitions are just for formal situations—like when submitting one or the other. If you’re confused, you can also ask your adviser; each school or institution may have their own definitions of the terms.