How to defend your PhD dissertation

So, I made it. Yiihaa! Four years culminating into one day. My first post as a fresh Doctor in Operations Management will be my reflections on giving the defense. I hope the thoughts will be somewhat helpful or comforting for all those shivering PhD candidates yet to come. One thing’s for sure; I’ve got respect for the process. A PhD defense is – and should be – a serious ceremony. Yet, it can be one of the best days in life. These tips and tricks on how to defend your PhD dissertation are not just my own; many thanks to all the professors at NTNU who shared their advice with me. I’ll pay it forward.

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Nerve coolers

Yes, it’s the lamest advice, but it is still the best: you are the expert in the room. Trust your brain. No one in the world has recently spent so much time as you on this specific topic. Your supervisor has found your thesis worthy to be defended. So has the committee. You will pass. Everyone knows that. The only one still doubting is you. You know all the weaknesses of your own work. The opponents in the committee don’t. They know the weaknesses of their own work…

In fact, the committee has better reasons to be nervous than you; the audience want you to succeed and be brilliant. It is not everyone against you, it is everyone against the committee. The opponents want to appear smart but friendly. An experienced professor told me that in many cases they are so hung up in performing with their questions, that they don’t really pay attention to all your answers. After all, it’s a small research community and what goes around comes around. They’ll be much nicer than you fear.

Dress up for your defense. This is your day. If you’re going to have a tough time, have it with style. The audience does not just listen to what you have to say, they observe it. If you look good, your work looks good. The last thing you want to worry about when the opponents start lightening up the fire is whether your shirt matches your socks.  Treat yourself with a complete new outfit. You certainly deserve it, and it boosts your confidence and cools your nerves.

Presentation skills

Presentation skills is king. It is probably too late to become a TED-level speaker two weeks prior to the defense, but it’s not too late to nail an excellent presentation of your work. Make sure you get these basic things right: simple slides, flow and timing. Practice? Yes, of course. A run-through with colleagues is essential and tremendously helpful. But don’t overdo the practice part; if you know it by heart, it will get boring. Leave some room for nerves and energy. I recommend about three to five full trials, of which at least one in the actual defense room.

A difficult thing during a PhD defense is to reach your audience. Probably, your public defense draws a rare mix of friends, family, expert colleagues, other PhD candidates and wild-card walk-ins. How can you possibly deliver a speech that will reach them all? Make all of them feel smarter. Tell a story: what was the problem, what did you do, and what did you find that contributes to research and practice (repeat if several papers). That simple story will offer something for anyone.

The discussion

Your presentation is delivered. It went well. Now, don’t let your guard down. This is when the real defense start. If you got a written comment to your thesis from the committee you should have read it carefully and practiced a few responses to the obvious questions in it. I also hope you have already attended a few other defenses and asked professors for advice before you’re up. In any case, the most important advice is this one: This is the day to be humble. All research has weaknesses. Be confident about your choices and results, but agree that it could have be done better or differently. That will take you far.

Some questions deserve a few seconds thought. Write them down as soon as you hear that there are several questions bundled into one. Here’s a few standard openings that might come in useful: “A good point, I’m aware of that debate…”; “Yes, on one hand (…) but on the other hand…”; “I see your point, but I respectfully disagree, because…”; “I’m not an expert in that area, but here’s how I view that…”; “I understand that question as follows… (tweak it into something you’ve prepared to answer)”. In general, talk more if you’re confident, be brief when you’re on thin ice (this is much more tricky than it sounds like!). Use examples if you have them. If you’ve done case studies, refer to them. No one knows what you have seen and heard, hence you own the truth and can speak freely and in pictures. Examples come with the additional benefit of being interesting for the audience.

Finally, the PhD defense is not meant to be a walk in the park. There will be a few really tough questions, and it can therefore be good to know of a few “life savers”. The most usual one, which you can pull a few times and that will quickly end any difficult question is this one: “An excellent point, I would like to look into that in the future” or “Unfortunately, I did not have the time and resources to investigate that, I’ll leave it to future studies”. If you need to buy yourself some time, and you know that you have treated the question somewhere in you thesis, you can lend this dry joke from me: “Hmm, let me read what I think about that…”. If every escape is blocked, and you painted yourself into a corner, you “get a free life” by simply admitting “I don’t know the answer to that question”. But note; this last-resort-option can only be used once, so save it carefully .

Go defend your PhD dissertation

If there’s one advice that trumps all the others, it has to be this one: Smile, have fun, enjoy YOUR day! I wish you the best of luck.

16 thoughts on “How to defend your PhD dissertation

  1. Thank you very much for all of your advices! I´m defending on March 13th and I´m sooo nervous, it was very helpful to read you!

  2. This was a great read! I’m defending mine tomorrow and you had good points I will hold on to. Thanks again!

  3. Thank you very much for the post. I am close to my defense. My advisor and most of my committee is very supportive of my work. However one member is creating nuisance over a published (peer-reviewed journal) part of my dissertation and essentially making comments in academically unprofessional tone? I need him to sign my dissertation. If you or someone can offer some thoughts on this …

    • Congrats on beeing so close! Some people have bigger egos than others, my advice would be to be diplomatic with him; thank him and let him know that you “see his points”, and that “no research study is perfect”, but that “you believe in your work and there is clearly some merit in it ” (after all it has been published). I am sure he’ll back off eventually if the rest of the committee wants to accept it. Good luck!

    • David; answer is unfortunately “depends on your university traditions and committee”. My advise is to not bore the h.. out of the other attendants. Good luck!

  4. My dissertation defence is on 15 December. I don’t have many experiences in doing presentation in English, so this adds to the level of my nervousness. Just curious if actually you were this calm before your defence took place.

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