Ph.D. research must demonstrate the student’s ability to conduct an original, coherent, and independent investigation, to abstract principles, and to interpret the results in a logical manner. The student must pass a Ph.D. Proposal Examination, designed to assess the plan for completing the Ph.D. research, within the first three years of residence. Ph.D. dissertation and oral defense must be completed within six years of passing the Ph.D. Qualifying Examination.