The Biological Sciences Division (BSD) establishes the following enrollment limits for PhD students:
- Students matriculating before Autumn 2016: 10-year limit (40 quarters) No adjustments for leaves of absence
- Students matriculating Autumn 2016 through 2024: 9-year limit (36 quarters)
- Students matriculating Autumn 2025 or later: 8-year limit (32 quarters)
For 2016 or later cohorts, the Dean of Students Office will extend the enrollment time limit for documented leaves of absence (upon student/program request) and unusual circumstances (upon program request).
The Division notes that average time-to-degree completion remains below 6 years, making cases approaching these limits exceptional. Students reaching their enrollment limit will be administratively withdrawn but retain eligibility to defend their dissertation if their dissertation is deemed defensible. See University Policy on Time Limit Administrative Withdrawal for details