Defense and Evaluation

The Graduate School of Arts and Sciences requires that all doctoral dissertations undergo a formal examination in which the student has the opportunity to discuss and defend the dissertation with respect to its sources, findings, interpretations, and conclusions before a committee of faculty knowledgeable in the student's field of research. All faculty members of the defense committee are expected to be present at the defense.

Only the candidate and the approved members of the dissertation defense committee may be present during the defense. Columbia University policy does not allow spectators or other individuals to attend a defense. Audio or video recording during the defense is strictly prohibited. No exceptions to this rule are permitted unless recommended through the amended Americans with Disabilities Act (ADA) and Section 504 of the Rehabilitation Act.

The dissertation defense is a milestone ideally reached with all five members of a student’s dissertation committee present. When a committee member can only participate from afar, an accommodation may be made by employing audio or video conferencing during the defense. A maximum of two members of the dissertation defense committee may participate remotely, but the committee chair and the sponsor must be present at the defense.

The committee chair will register the need for remote participation on the GSAS Application for the Dissertation Defense, and will sign the voting sheet on the absent member’s behalf after the defense. Committee members who must participate remotely are requested to submit comments, questions, and a provisional vote in advance so that the defense exercise may proceed in the event technical difficulties are encountered during the proceedings.

The dissertation defense committee may convene when one member is prevented from participating by extreme circumstances at the time of the defense. Such a last-minute absence will count toward the total of two members allowed to participate remotely. If possible, the absent member should, before the defense, submit a report containing comments, questions, and a provisional vote on the dissertation's approval. The committee chair will convey these questions to the candidate at the defense and rule on the quality the responses made. If circumstances prevent the submission of a report before the defense, the absent member’s report should be sent as soon as possible after the defense to the dissertation defense committee chair and to the dean of the Graduate School. The committee vote will not be considered final until the report is reviewed and the defense committee chair determines whether any further action is warranted.

The examination normally lasts two hours. The candidate is generally asked to begin by summarizing the pertinent background and findings. Such summaries should be limited to no more than fifteen minutes. The chair of the committee is responsible for allotting time, normally allowing each faculty member twenty minutes in which to examine the candidate.

Typically examiners will have a lists of points they wish to discuss. These points are either substantial or editorial. Unless it is necessary to show that a very poorly written dissertation must be entirely rewritten, examiners should not take up these editorial comments one by one. Examiners should give their sheets of notes on these matters to the candidate, leaving time to examine matters of substance.

When all examiners have finished their questioning, the chair asks the candidate to step outside the examination room, and wait for an invitation to return.

During the discussion period, the committee makes its decision on the defense and votes on the outcome. Upon the candidate's return to the room, the chair will inform the candidate of the committee's determination, and provide further instructions.

All dissertation defense outcomes are determined by a minimum of three votes in one category (Approved as Submitted, Approved Pending Revisions, Referred, or Fail). Members of the defense committee should consider themselves independent examiners, and should therefore not feel pressured—or be pressured—to join the majority opinion of the committee. While respecting disciplinary differences, the PhD degree should only be awarded to research that represents an original contribution to the field, no matter the field. If a dissertation receives two votes in the Referred and/or Fail categories, the Voting Sheet and dissertation must be submitted to the Dean of the Graduate School of Arts and Sciences for review. In such instances, the candidate should be informed that the committee’s vote was not conclusive, and to await further communication from the Office of the Dean. For more information, please review the defense vote policies

The following dissertation defense outcomes took effect on January 1, 2017.

Approved as Submitted

The committee may ask that minor revisions or corrections be made before the dissertation is deposited. The committee should convey an account of those minor revisions to the candidate at the defense. These minor revisions should be completed to the satisfaction of the sponsor within one month after the defense. If for exceptional reasons more time is needed, the candidate may apply for an additional one-month extension by submitting a letter to with the request.

Approved Pending Revisions

The committee may ask that revisions be made before the dissertation is deposited. The chair of the defense committee will ensure that a written description of those revisions be provided to the candidate typically by the sponsor—at the defense or shortly thereafter. Care should be taken to distinguish between revisions requested and recommendations given for future thought or research beyond the dissertation. These revisions should be completed to the satisfaction of the sponsor within six months after the date of the defense. Any member of the committee may ask to review a copy of the revised version of the dissertation. If for exceptional reasons more time is needed, the candidate may apply for an additional two-month extension by submitting a letter to with the request.


The committee believes that substantial work must be undertaken on the dissertation by the candidate before it can reach a recommendation to award the degree. A detailed written description of the reservations about the examined dissertation as well as of the revisions required should be provided to the candidate by the sponsor at the defense or shortly afterward. At the time of the defense, a subcommittee composed of at least three unanimously agreed upon members of the original committee (and including the sponsor) will be formed. The specified revisions should be completed to the satisfaction of the subcommittee within one year after the date of the defense. A statement from the candidate indicating the specific changes made in response to the committee’s request for revision must accompany the revised version, and both be sent to the sponsor. The sponsor will share the statement and the revised version with the members of the defense subcommittee, each of whom must communicate explicitly to the sponsor their appraisal of the revisions undertaken. A majority of the subcommittee must approve the revised version for the candidate to be recommended for the degree. The dissertation will then be recommended for award of the degree.


The committee believes that the dissertation is not acceptable, and the candidate will not be recommended for the degree. No candidate may have a second defense unless the Dean of GSAS concludes, upon evidence provided either by the candidate or by a member of the committee, that procedural irregularities occurred during the defense.

Dissertations defended after the 2012 Commencement ceremony will only be eligible for departmental distinction, should a department institute such recognition.