The doctoral dissertation is the capstone of the Biostatistics PhD. It represents a substantial, original methodological contribution to the field and demonstrates the student’s ability to conduct independent research at a professional level. While the format may vary, the work is typically equivalent to three publishable papers and is expected to advance statistical methodology with clear connections to important biomedical applications.
A successful dissertation shows both depth (e.g., rigorous theory or methods) and relevance (e.g., through applications or collaborative science that highlight the value of the methods). Communication is also central: students are expected to explain complex methods clearly, both in writing and in public presentation.
- Scope: Novel methodological research, often organized around 2-4 related projects.
- Integration: Demonstrates a coherent research agenda rather than a set of unrelated papers.
- Quality: Suitable for peer-reviewed publication in leading journals.
- Timing: Typically completed in Years 4-5, with submission within two years after the preliminary exam.
Oral Preliminary Examination
The oral preliminary examination demonstrates readiness to lead independent methodological research and sets the approved plan for the dissertation. It comprises a written dissertation proposal (NIH/NSF fellowship style) and an oral exam with the student’s PhD committee. The exam is completed by the end of Year 3 spring semester .
- Committee: At least four members; majority from the student’s major research area; includes a Minor Area Representative (MAR). The committee must be approved by the Graduate School ≥30 days before the oral prelim.
- Written proposal: Typically ≥12 pages (plus references); circulated to the committee with sufficient time for review and feedback.
Final Oral Defense
The public defense includes a seminar followed by committee questioning (with an optional closed session). After deliberation, committee members vote to pass or require additional work. Passing the dissertation defense requires at least four “Pass” votes, no more than one “Fail” vote, and no negative vote from the chair/co-chair.
Dissertation and Graduation Milestones
It is recommended that the candidate meets with the dissertation committee regularly to keep the committee up-to-date on the dissertation research progress. Because of the review time (up to two years) involved for some statistical journals, the student will not be required to have the dissertation published before being approved. However, it is strongly encouraged that the student have at least one draft statistical manuscript ready for submission by this time. Additionally, students are strongly encouraged to have one or more collaborative publications published or in press. Specific deadlines are indicated in the table below:
| Graduation Time | Application for Graduation | Initial Dissertation Submission by 5:00 pm |
Deadline to Defend Your Dissertation |
Final Submission of Dissertation by 3:00 pm |
|---|---|---|---|---|
| September 2025 | June 11 | July 3 | July 18 | August 1 |
| December 2025 | October 1 | November 7 | November 21 | December 5 |
| May 2026 | February 1 | March 18 | April 1 | April 15 |
Preparation of Dissertation: Basic requirements for preparing and submitting the dissertation are prescribed in the “ Guide for Electronic Submission of Thesis and Dissertation ”.
Application for Graduation: Candidate must apply to graduate in the DukeHub student center at least one month before the dissertation is presented and no later than the dates listed in the table above. This application should indicate the approved title of the dissertation and be approved by both the DGS and the dissertation advisor.
Initial Dissertation Submission: The Initial submission of the electronic doctoral dissertation must be submitted via UMI/ProQuest . This submission must take place at least two weeks before your oral final defense and no later than 5:00 pm on the deadline dates indicated in the table above. Before the initial submission, the dissertation advisor must receive a complete draft of your dissertation. The candidate must request the advisor to send an Advisor Letter (see sample letter in Guide for Electronic Submission of Thesis and Dissertation ) and the DGS to submit a Defense Announcement to be emailed to the Graduate School, with the student's name as part of the subject line, to: gradacademics@duke.edu .
The doctoral dissertation should normally be submitted and accepted within two calendar years after the preliminary examination is passed.
Final Oral Defense :
It is recommended that the candidate have their committee’s approval for the presentation of the final oral defense. At the end of the fourth (or fifth) year, the student will present their dissertation work orally in a public forum, advertised and open to other members of the department and university. Questions from both committee members and other members of the audience will follow the presentation and will serve as the student's final examination. Additional questioning may take place in an optional closed session attended only by the student and committee members. Afterward, the student will be dismissed so that the student's committee can deliberate and vote on whether to pass the student or to require additional work.
The Director of Graduate Studies will send a notice of the time, place, date, student's name, title of dissertation, and names of the committee members to the Graduate School at least two weeks before the scheduled oral dissertation defense. Members of the doctoral committee must be given at least two weeks to read the dissertation before the defense. A committee finding that the candidate has passed or passed with minor revisions should sign the doctoral examination card, as well as the title and abstract pages, with the understanding that the dissertation advisor sees and approves the revisions before the dissertation is submitted. The student has up to one month after the examination to make changes in the dissertation requested by the committee to the satisfaction of the dissertation advisor. If revisions are beyond what are considered “minor” by the committee, then the committee must withhold its signature on the required documents until the dissertation advisor has approved the revisions. A candidate who has failed the final doctoral examination may be granted a re-examination on the recommendation of the supervising faculty member no sooner than six months after the date of the failed oral defense.
After the defense, the dissertation committee's pass/fail decision will be recorded by the committee chair on an electronic exam card form. This form will be pre-populated by Graduate School staff and emailed directly from The Graduate School to the dissertation committee Chair and DGSA at least 24 hours before the scheduled defense. Students graduating in Fall 2020 or Spring 2021 will not need to submit signed title pages or abstract title pages. Students will receive instructions regarding the electronic submission of the advisor-approved embargo document in the email they receive from ProQuest after their initial submission has been reviewed by a TGS administrator. Graduating students must also complete the Survey of Earned Doctoral (SED), the Graduate School’s Exit Survey, and the Duke Placement Survey. Inquiries about how to complete these requirements should be addressed to The Graduate School.
Final Submission of Dissertation : All defended, completed PhD dissertations must be submitted to UMI/ProQuest by 3:00 pm on the deadline dates indicated in the table above.
Additional Information may be found on the Graduate School website.