Course work and comprehensive exams are preliminary steps in a Ph.D. program that prepare the student for the dissertation. The goal for a dissertation is for the Ph.D. student to make an original contribution to a particular academic discipline. The first step in making an original contribution is identifying a problem. Defining a problem involves a thorough knowledge of the relevant and related literature in the field and the ability to see issues that researchers have not addressed or have addressed inadequately.
Addressing the problem in a dissertation requires collecting and critically assessing all the relevant information and data. Information gathering involves a number of critical thinking skills. Information gathering requires making sense of multiple documents that often have contradictory facts and details and critically reflecting on and interpreting the information and data. Gathering the information for the Ph.D., depending on the specific discipline, requires the ability to qualitatively and quantitatively evaluate and organize the material. Ph.D. students working in the humanities spend a majority of time in libraries interpreting literary texts. Ph.D. students in the social or hard sciences may spend a lot of time in forming research questions and doing experiments.
The successful Ph.D. student must be able to use the gathered information and literature thoughtfully to create an original solution to the problem. The Ph.D. student has to have a tolerance for ambiguity because most academic problems are capable of multiple solutions. However, even though there are multiple solutions to a problem, some solutions are more persuasive and convincing than others. The solution presented in the dissertation must make a convincing argument that is persuasive even to those in the field that hold an alternative point of view.
The dissertation presents the solution in a written form, and the dissertation defense requires the Ph.D. student to defend questions and objections to the dissertation in an oral examination. The writing stage of the dissertation is the most difficult part of completing a Ph.D. student. It is the obstacle that prevents many Ph.D. students from completing their degree. A number of critical thinking skills are necessary to successfully write a dissertation including organizing and arranging the material, writing persuasively, reflecting on and editing what you written critically and possessing time management skills. The oral defense demands the ability to respond to critical questions in a thoughtful and convincing way, the ability to stay calm under the pressure and the ability to respond the serious objections that you may not have been aware of before.