The graduate program is divided into two phases. During the first phase, when the student is actively taking a full course load, students are considered precandidates. Coursework, teaching, and independent research and study prepare students to participate as research scholars in particular fields within political science. Once a student demonstrates mastery of these fields, the student enters the second phase, called candidacy. During candidacy the student plans, executes, and defends his or her doctoral dissertation. While a student is a precandidate, the student focuses on two subfields. One becomes the major field, and the second is the minor. Over the first three years, ordinarily students take four or five courses in their major field and three or four in their minor. In addition, all students must complete a ''cognate'' required by Rackham that consists of four credit hours in approved graduate-level courses in a field outside their major and minor. Usually these credits will come from the same department, but a student might tie together courses from different departments. A student enters the candidacy phase only after successful completion of two preliminary exams and completion of coursework requirements.