Best Time Of Day For A Dissertation Defense
First, I have never heard of any research backing up the idea that defenses will be more less successful based on the time of day the defense is held.
Second, the best time to defend is whenever your committee can actually make it. When I defended, my goal was to get get at least three of our four committee members in same physical room (one non-chair member could attend via video). Within a six-week window, I felt lucky to find any two hour-window to schedule the defense.
Finally, you are overthinking things. Pour your energy and concern into the content and remember that if your committee is encouraging you to defend, it's because they think you are ready. Surprises are unlikely.
Of course if you are in the enviable position of having to choose a time of day, I personally like defenses at the end of the work day so that you can head out with others — e.g., students, family members, maybe even committee members — for a celebratory post-defense drink or meal.
Ten Tips for Surviving your PhD Defense
These previous posts were mostly written from my point of view, and tied very closely to my personal experience during the preparation for my defense and the Big Day itself.
Now that it's almost been a year since my defense, and the whole experience has been digested and thought over, I want to give something of more general value (or at least, that's what I hope).
Here is my list of ten tips for the defense, regardless of your field.
1. Know your committee
If you have not had the chance to meet your committee members before the defense, then at least read up on their latest work, and use this knowledge to get an idea of what type of questions you can expect from them. If possible, ask some people who had your committee members for their defense to see how they behave during the defense. Do they like quizzing you on general knowledge about your research field, do they like to go into the nitty-gritty of your research, do they care more about the broader societal impact?
2. Know your assumptions and limitations of your conclusions
It's very unlikely that your PhD thesis is the Holy Grail, the Answer to Life, the Universe, and Everything (well, we know that is 42), or the Theory that Replaces All Previous Theories. So, revise the assumptions that you made in your analysis parts. Know the limitations of the assumptions, and prepare for questions that might be just out of the scope of your assumptions (and have an idea of what to do when your assumptions are not valid).
3. Bring something visual
Bring something to show - this could be a scale model of your experiment, a simple "experiment" to demonstrate a basic principle that you used, copies of important papers on which you based your work to put on the projector, some additional graphs,... If you got an idea from the meetings with your committee members what they might ask (something that is maybe missing in your dissertation), then work through that problem and bring it along with you to show them.
4. Prepare for questions that are right at the edge of your work
One of my colleagues told me the following: "Your committee members are going to look at the periphery of your work, and tie that to something they have been working on (and find the intersection between your respective fields of expertise), and from there they will try to pull you out of your circle of comfort and into their own circle. That's where the dangerous questions come from." Absolutely true.
5. Trust yourself
Come on, you've come so far as to actually defend your thesis, and by now you are the big expert in your (tiny) field of expertise. You've been working on this dissertation for 3 to 4 years, and unless you were playing Farmville or Angry Birds all the time, you should know this stuff by heart.
6. Brush up on your literature knowledge
When did you write your literature review? Chances are, you wrote that maybe 2 years ago. In those 2 years, a whole slew of new papers have been published. Try to identify the most important papers of the last year, read up on the latest developments, and -if possible- attend a few conferences to know what is hot at the moment and what new research folks are working on. Be ready to show your committee members that you know what is going on.
7. Know your schedule for the Big Day
Know who has to be where at which time, and communicate this to all parties involved (promotor, committee members, paranymphs, friends, families and fans). Since I'm a bit obsessed with planning, and because I had a nightmare a few weeks before the defense that my promotor forgot about my defense and arrive too late, I had my itinerary for the day very well planned out, and I repeated to everybody ad nauseum where they were expected to be and at what time.
8. Eat well
And now for the Granny Eva advice: eat your veggies in the days before the defense for great energy. Right before the defense, it depends on you personally. I think I ate some bread with cheese to avoid being so hungry that I'd want to eat my committee or faint during the defense. Just avoid that food becomes a worry (right) before your defense. Oh, and of course, don't drink yourself into stupor the night before, thinking that it might help you relax.
9. Get enough sleep
Zzzzzzs are good for your brain, so try to relax the afternoon and evening before your defense. I tend to get nervous and unable to sleep before big events, but I did all my magic tricks to make sure I'd sleep well the night before my defense (I washed my hair -for some reason I sleep better with wet hair and believe that fresh hair brings me good luck (don't ask)-, I spent some time reading a novel on my bed with my husband and cat by my side, I had everything packed up and ready for the next day,...) and I actually really slept very well and woke up feeling rested and refreshed (and nervous, of course).
10. Enjoy your big day
You're only defending once in your life, so enjoy it. Most likely, all your friends and family will be coming out to see the event and then celebrate with you - so except for big birthday bashes and weddings, you don't often get the chance to get all your loved ones together. You're going to be in the center of attention for a day, so bask in the light!
These are my best tips for the PhD defense. What worked well for you? Let me know in the comments below!