The terms "dissertation" and "thesis" are often used interchangeably, sometimes even by the same school. While a dissertation might be called a thesis, a thesis is rarely called a dissertation. Dissertations are an important part of a doctoral program, while theses are usually shorter pieces reserved for master's candidates and undergraduate students. The term "thesis" can also refer to a sentence outlining the main arguments of a work.

Types of Theses

There are two types of theses. The first is a sentence or two introducing the main ideas of a paper. In this context, a thesis will outline your main arguments, introduce research or make a claim about another person's work. The other type of thesis is much more similar to a dissertation. This variety of thesis is a research project submitted to an institution of higher learning. It is sometimes a requirement for graduation, but may also be an optional independent project.

Types of Research for Theses and Dissertations

The second type of thesis, the research project, is usually a synthesis of prior research. It might also make an argument based on this research. A master's student in psychology, for example, might review protocols for treating depression and then make a recommendation for the most effective strategy. A dissertation, by contrast, contributes novel research to the field. A student writing a dissertation might propose a new theory or conduct a research study of her own.

Educational Level

Dissertations are reserved for students at the doctoral or Ph.D. level and usually serve as the final step toward achieving their degree. A thesis, by contrast, can be done at every level of education. Some undergraduate students compose undergraduate theses before graduating. Typically, however, a thesis is the domain of a master's degree student, who might be required to show a certain level of knowledge and research acumen prior to graduating.

Defense

At most schools, both thesis topics and dissertations have to be approved by an adviser. They might also go through several rounds of revisions before being published, and these revisions are typically based on the critiques of professors or an adviser. Students writing a dissertation, however, have to formally defend their paper in front of a committee of experts. This defense can last for several hours, and students can spend weeks or months preparing for it.