The form and general requirements for the comprehensive exam varies according to the faculty or department, degree sought, university, and country, but typically tests knowledge of the student's subject area and two or more related areas, and may be used to determine a candidate's eligibility to continue his or her course of study. Typically, comprehensive exams consist of three written exams and an oral examination.
In some university departments, graduate students seeking a Ph.D. degree must take a series of written cumulative examinations on the subject of their study in the first year or two of the Ph.D. program. These cumulative exams are often given on a pass/fail basis and a graduate student who seeks to continue in the Ph.D. program must pass a minimum number of these cumulative exams. After this minimum number of cumulative exams is passed, this degree requirement is considered to be met, and the Ph.D. student no longer takes these exams but continues work on other Ph.D. requirements.
Comprehensive examinations are typically based on a reading list agreed upon by the student and his or her committee, which is staffed by the primary supervisor and several advisors, normally professors at the university, but not necessarily in the same faculty. This reading list may comprise dozens or hundreds of books and other works.
The examination may take the form of a long paper which may take several months to write, or a shorter paper on a choice of topics which the student has 24 hours to complete.
Ph.D. students at some Canadian universities must complete their comprehensive exams by the end of their second year; those who fail to pass with a sufficiently high mark may retake the examination usually only once. Failure to pass a second time will normally result in expulsion from the program. Students who pass are distinguished with the title "Ph.D. candidate."
In some US graduate programs, particularly in the natural sciences, the majority of students do not have master's degrees when they begin graduate work, and the successful students will earn doctorates without getting master's degrees on the way. In these programs, a student who does not pass "comps" or "prelims" on the second try will generally be allowed to earn a terminal master's degree but not permitted to become a candidate for a doctoral degree. Technically, at many institutions being formally accepted as a candidate for the Ph.D. automatically entitles the student to a Master of Arts degree, but few students actually bother submitting the paperwork to apply for the MA degree after passing prelims. Comprehensive examinations of this type are more common in the sciences and some social sciences, and relatively unknown in most humanities disciplines.
In the second and third years of study, doctoral programs often require students to pass more examinations. Programs often require a Qualifying Examination ("Quals") or General Examination ("Generals") or Comprehensive Examinations (again, "Comps"), testing students' grasp of a broad sample of their discipline, and/or one or several Special Field Examinations ("Specials"), testing students in their narrower selected areas of specialty within the discipline. If these examinations are held orally, they may be known colloquially as "orals". For some social science and many humanities disciplines, where graduate students may or may not have studied the discipline at the undergraduate level, these exams will be the first set, and be based either on graduate coursework or specific preparatory reading (sometimes up to a year's work in reading). In all cases, comprehensive exams are normally both stressful and time consuming, and must be passed to be allowed to proceed on to the thesis. Passing such examinations allows the student to stay, begin doctoral research, and rise to the status of a doctoral candidate, while failing usually results in the student leaving the program or re-taking the test after some time has passed (usually a semester or a year). Some schools have an intermediate category, passing at the master's level, which allows the student to leave with a master's without having completed a master's thesis.