A Ph.D. thesis, or dissertation, is intended for the doctoral candidate to demonstrate that he or she has mastered the art of conducting original research, analyzing problems and situations, and drawing conclusions that follow logically from that research and analysis. There are, however, different approaches that students can use in producing a research paper; in effect, there are different methodologies that can be utilized. Because a dissertation is reviewed by a committee composed of scholars specializing, in whole or in part, in the field covered by the research, and because the point of the exercise is to demonstrate the ability to prepare a scientific study, it is expected that the student will discuss in the paper the methods used in carrying out his or her research, and the tools employed in analyzing the material that has been accumulated.
The term "Nature of the Study" refers to the presentation of this information. It does not have to be long; sometimes a single paragraph will suffice. It does, however, have to be academically rigorous in its presentation. This section of the dissertation must spell out the type of analysis used -- for example, quantitative or qualitative, or some combination of the two. Is the dissertation comprised primarily of a case study involving a single development or phenomenon, or is it a comparative analysis involving multiple actors, events, developments, etc.? Is statistical analysis used in drawing conclusions? Are experiments conducted? These are they types of questions that the "Nature of the Study" section should address.