The Preliminary Oral Exam is the last exam in your way to a Ph.D. degree before the actual thesis defense itself. At this stage, you have a research adviser who will guide you to completion of the Ph.D. degree.

Only after you pass the oral exam, you can register for thesis credits (you need 24 of them before you complete your degree). And after you finish taking thesis credits (you need at least two semesters to do so), you will reach “ABD status” (All But Dissertation).