The Last Big Hurdle: How to Prepare for a Successful PhD Defence

It’s the moment almost everyone who completes a PhD both dreads and looks ahead to for years—the defence. It signals a major achievement, but in people’s imaginations, it can seem like the stuff of nightmares… standing frozen in front of everyone, unable to answer a tricky question posed by a committee member and feeling like you must look incompetent. The format of a doctoral defence varies from field to field, but the worst fears of the candidates remain largely the same. Though most people know it probably won’t go so badly, the open-ended-ness can certainly be intimidating- you’re up there alone in front of a panel of experts who get to ask you whatever they’d like, and you may have to deliver your answers in front of an audience of your peers. There are few experiences in academic life more geared to be stressful for the person at the centre of them.

It doesn’t have to be that bad. I spent the weeks leading up to my PhD defence in a state of near panic, but I can honestly say that once it actually got underway, I sort of enjoyed it. You’re the star of the show and get to walk your peers through the finer points of your research. It can be a really invigorating experience. So let’s try to break this down into bite-sized chunks and look at strategies and tips for making your defence an event you might actually look back fondly on.

What the committee wants

Let’s start with what the committee is actually looking for. They want to see a firm grasp of the subject matter, an understanding of the implications of the work, and the ability to see weaknesses in the methodology and possible routes to take for future work. This means creating a presentation that gives a clear, logical overview of your topic, the question you’re addressing, what you did, your results and conclusions, and where the research can go from here. Remember, your jury members are not out to get you. The questions you receive from them will generally fall under one of three headings- those that test your subject knowledge, those that clarify a confusing point, and those that arise from genuine curiosity. If your presentation does a good job of conveying your knowledge of your topic, you can expect more questions from the second and third categories, allowing you to think of the defense more as a conversation amongst experts than a test from on high.

How to prepare

Practice is obviously very important here. Once you’ve put your talk together, find a trusted friend or mentor (ideally, several of them) who knows your field to go through it with you. They can both help you to pare down unnecessary parts and point out logical leaps you may not have noticed because you’re so close to the subject matter. You also want this to be a person who will ask you tough questions and try to spot holes in your reasoning, so choose your test audience carefully. It can be tempting to spend a lot of time obsessing over your slides, trying to make them perfect, but there’s a lot of studying you’ll need to do to be ready for more tangential questions, so don’t lose too much time this way.

Even though you have lived and breathed your thesis topic for years, it’s a good idea to give your thesis a complete re-read just to make sure you really know what’s in there. It may have been months since you finished writing it, and parts may have gotten a little fuzzy since then. Make sure you know why you used the methodology that you did, be able to justify any conclusions you’ve made, and if there are mistakes, admit them openly at the defence and be able to talk about what you should have done differently—the committee isn’t looking for perfection, they’re looking for clear thinking and thorough consideration of methodology.

This is also a good time to review important topics that are peripheral to your work; this will allow you to answer some of the questions designed to test the limits of your broader knowledge of your field. One of the best pieces of defence preparation advice I’ve ever heard is to find out what each of your committee members’ professional interests are, and do a bit of reading on those topics. There’s a very good chance that they’ll ask you something that’s related to their own work, because that’s familiar ground to them, and you may be able to anticipate these questions this way.

Finally, though it’s less and less of a problem as technology improves, you’ll want to make very sure ahead of time that all your presentation gear works and connects properly to the display equipment in the room where your defence will be. No one wants to be running around at the last moment looking for a dongle they didn’t think they needed, or have their laptop’s battery run out partway through the defence. Check that your slides look the same way on the projection screen as they do on your computer- not cut off or too dark. It also doesn’t hurt just to spend time in the room in which you’ll be presenting, to get a feel for the place and see where everything will be positioned.

Common questions and ideas to think about

General

• What makes your project original, and how does it answer a previously unanswered question? What have you contributed to the body of knowledge on this topic?
• Why was this question important to ask? Why do we care about what your findings reveal? (Hint: “Just for the sake of knowing” is not an acceptable answer here.)
• Did the focus of your project change over its course? If so, explain how and why.

Methodology

• Why did you choose your methodological approach (including your statistical analyses)? Why is it superior to or more appropriate than all other methodologies?
• Talk about the difficulties you experienced with your methodology and how you addressed them.
• What are the limitations of your study design/methodology?
• Explain how your data represent an appropriate source of measurement to address your question.
• Is the amount of data gathered sufficient to address your question? Why or why not?
• If you could do it again with unlimited time and funds, how would your methodology change?

Conclusions

• What would you say is the most important “take-away” message of your work?
• Does your work have wider implications for other disciplines in your field?
• How do your conclusions support or contradict the existing literature?
• Are there alternative ways your data could have been interpreted?
• Speculate about what broader implications your research could have, but which aren’t addressed by your data, or were outside the scope of your project.

Next Steps

• If you were to continue on with this area of research, what would you do next to further your results? Is there a closely related “spin-off” question that needs to be answered?
• Propose an experimental design to test this related question. What results might you expect to see?
• Where do you think this field of study is headed in the next five to ten years?

Tips, tricks, and stress management

• Practice the first few minutes of your talk until you can do it on ‘autopilot’; this will give you a bit of time to relax into your presentation, get your thoughts in order, and begin talking more confidently.
• If your defence is open to the public, ask a few supportive friends or colleagues to sit where you can easily make eye contact while you’re talking. Seeing a friendly, smiling face can be encouraging and help you to relax.
• Don’t forget to review the newest literature in the weeks leading up to your defence—one or more important papers may have been published in your field since you wrote your thesis, and you’ll want to know about them.
• Have a hard copy of your thesis on hand during the defence. It’s much faster to flip to a physical page when asked about a particular section of the text. If this really isn’t for you, be sure you have a quick way to move through pages on your computer.
• Eat and drink the same things you normally would on the day of your defence. Your stomach may be extra sensitive in response to the stress, and you don’t want to surprise it with anything new. And go easy on the caffeine… jittery-ness will not help you to manage your stress!
• Try to let your enthusiasm for your subject matter show; your audience will feel more positive about your talk if they can see that you really find the work fascinating.
• It’s fine to take a moment to think about your answer before responding. The silence isn’t as long or as deafening as you think it is. And if you don’t know, just admit you don’t know—it’s okay to not know everything.
• Dress well, but comfortably, and try to project confidence. If you can speak to your committee as a group of your peers, it will reflect well on your growth as a scientist in training- and demonstrate you are someone who deserves to be awarded their doctorate.
• Don’t forget to publicly thank your advisor, your committee, and any other key people involved with your project for their time commitment and investment in your career.
• When planning post-defence festivities, be aware that you may be more tired, both mentally and emotionally, than you expected. Don’t ask too much of yourself in the hours following the event.

A bit of encouragement

Above all, there are two things you need to remember while preparing for your defence. First, your advisor and committee would not have allowed you to proceed to this point if they didn’t think you were ready. They want to see you succeed and, altruism aside, it would reflect badly on them as well if you were to fail. Trust that they’ve made the right decision. Second, after years of delving into your little corner of the scientific world, no one knows your thesis topic better than you do—not even your committee. Marshall your facts and feel confident in knowing that on this topic, you’re the world expert.