The exams will be given shortly before final exam week in Fall and Spring quarters. Information will appear on the department web site around the 3rd week of the quarter. The deadline for signing up will be a few weeks before the exams.
There are 4 problems per exam. You select 3 during the 2-hour exam period. The Graduate Committee looks at the exam and decides whether or not you show a reasonable amount of understanding of the subject. In that sense the result is simply a boolean yes (pass) or no (not a pass). To help us decide, we initially grade each problem on a scale of 0-20, resulting in a maximum score of 60 points. Roughly, scores comfortably above 30 pass, while scores within a few points of 30 could go either way. Normally, a good, solid solution to at least one question is a necessary (but not sufficient) condition for passing.
Note that the initial scores on a paper are just that: initial. The Committee reviews the exams after that to make a final determination. There may be differences in scores between graders and we pay particular attention to this in cases where it makes a difference in the outcome. But, again, the initial scores you see are a guide for the committee and borderlines will be evaluated for a reasonable understanding of the subject.
In order to pass the comprehensive examinations, a student must pass all 4 parts. A student passing only 2 or 3 parts does not have to retake those sections, while a student who passes fewer than 2 parts must retake all 4 sections.
A student who has not completed all 4 exams after 3 attempts may only retake the remaining exams with permission of the Graduate Committee. At that point, if the student has been making progress, the Committee may allow an additional attempt after the student discusses a study plan with the Graduate Coordinator. If it's felt that the student is not making sufficient progress, the Committee may require that the student retake 1 or more courses with grades of B or better before taking the exam again. Eventually, the Committee may choose not to permit an additional attempt due to repeatedly inadequate results.