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Ph.D. Thesis

What is it?

Your defense is the final of the PhD big three: qualifiers, proposal, and defense.

Terminology: What are the different components?

  •     Dissertation: The document detailing your research

  •     Defense:  Oral presentation covering major points of dissertation

How do I know when I’m ready?

This should be part of an ongoing conversation (over several months) with your advisor starting before your proposal. You propose when you and your advisor feel you have clearly established the steps needed, or a roadmap, to get to your defense. You should start putting together your committee 2-3 months before proposing, and generally, you will want to propose about a year in advance of defending. The maximum time you can stay in the program is 6 years after passing quals, or 10 years after your initial start date.

How do I write the dissertation?

First, outline your dissertation with your advisor. When writing your dissertation, go chapter by chapter, sending each one to your advisor. Some of these chapters will be roughly based on the papers you’ve written. For some students, their dissertation content and direction may not change between proposal and defense, but this is not universal.

When should I schedule my defense?

Two weeks before the date of your defense, you will submit a completed draft of your dissertation to your committee.  They will return the document to you after your presentation with edits that should take approximately two weeks to complete.  Since these edits are due on the same day that final grades for a semester are due, most students schedule their defense approximately two weeks before final grades.

How do I prepare for the defense?

Your defense will be a roughly 45-minute long presentation covering major points of your dissertation (when preparing your defense, it helps to have an overarching theme). It is your responsibility (not the department’s) to pick a date for your defense. Plan far in advance, as faculty travel regularly and have tight schedules.


It is a good idea to start working on the presentation after submitting the dissertation (which should be submitted two weeks before your defense). You will go over your presentation with your advisor and lab mates. Remember that you don’t have to reinvent the wheel – reuse slides from conferences or other presentations you’ve done in the past.  All defenses, including presentation and questions, are open to the public (unless there any proprietary material), and people often invite their parents and friends. Lastly, make your committee happy, and get food (real food, not bagels) for your defense (this will be out of your own pocket).

Can I fail?

Yes, but this is highly unlikely provided that your committee is engaged with your research and is not surprised by what you present.  The proposal exists to lay out what you plan to include in your defense and give your committee a chance to provide you feedback before the defense.  If your thesis has changed significantly since the proposal, or your committee has changed, be sure to discuss it with your committee so that there are no surprises.  Almost everyone gets a provisional pass, which means there are corrections you need to make to your dissertation, which can range from days’ to weeks’ worth of work.

What advice do older students and faculty have for me?

  1. Bug Chris Hertz. Paperwork is confusing. He is there to help.

  2. The dissertation will often contain more detail than your papers. Think about what information will be helpful to future students in your research group.  If you are unsure of what yours should look like, consider getting examples from other students in your group or checking out the repository of CMU dissertations here.

  3. Meet with committee members individually in the months leading up to the defense to make sure that they know what you have been working on.  It’s also good to orient yourself to the expectations by attending others’ defenses before it’s your turn.

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