Hints for PhD Defenses
At Columbia, PhD defenses are generally not public, although CS usually allows a student audience. Defenses consist of four parts: first, the candidate introduces themselves, then presents a summary of their work, interrupted and followed by questions from the committee. Finally, the committee meets in private to discuss the presentation and dissertation.
While most of the committee will have read most of your thesis, you cannot assume that everyone has read every chapter.
The committee needs to be able to assess impact and depth. Usually, the committee has some idea of this before the defense, but whatever the student can say to make this assessment easier, perhaps just through emphasis, is likely to make the defense go much more smoothly.
Generally, the whole defense will not take more than two hours, but should take considerably less time. Part of the challenge of a defense is to convince the committee that you can summarize the important points of your work in a very limited time.
- Your presentation (and thesis) needs to address the following:
- What is the problem you are studying?
- Why is it important?
- What results have you achieved?
- Some committee members will want to know if the works has been published and where and how it was received. For example, if you have written software, indicate where it is being used, either for follow-on work or in some production or test environment.
- Have a list of your thesis-related publications as a slide. Indicate any awards that a paper may have received. For most people, it's easier to list some honor than "brag" about it in person.
- If you have presented your work in a conference or at job talks, be sure to anticipate and address the most common questions asked there.
- The committee should be handed a copy of your slides.
- Be prepared to briefly summarize your background (undergraduate degree, how long at the university, etc.)
- No more than 30 slides, plus "back up" slides with additional material in case of questions. The most effective way of making your committee members mad is to come unprepared with a stack of 80 slides and then madly skip through them.
- Number your slides, particularly if one of your committee members is linked in via speakerphone. Consider using some kind of remote presentation software.
- List your contributions early.
- When presenting your contributions, be sure to use "I" and not "we" so that the committee will know what aspects of the work where yours, and which were group projects.
- Keep discussions of related work very brief, but be prepared to answer questions of the "how does this differ from so-and-so's work" succinctly.
- You will not be asked to prove results again.
- Be prepared to back up any comparative statement with facts, in particular statements like "works better", "faster", "scalable" or "optimal". If you are presenting a protocol, how do you know that it works correctly?
- If you have multiple parts in your dissertation, consult with the committee ahead of time as to whether it makes sense to omit some of them for the presentation.
Hints for Dissertations
- It is better to focus deeply on a single area then to work on several topics, each of which is pursued to a moderate depth.
- Systems work must be coupled with implementation and some kind of numerical comparitive analysis to demonstrate the improvements from existing or alternate approaches.
- Your thesis needs a one page executive summary that a layperson should be able to understand. Test: give it to a relative of yours that does not have an engineering degree...
- You are likely only to defend a PhD thesis only once; your defense is a special occasion, so consider dressing appropriately, at least business casual, but a suit is not inappropriate.
- It is customary to provide refreshments for the audience, such as coffee, bagels, cookies and fruit, depending on the time of day.
The Role of PhD Committee Members
- Committee members (should) read the draft thesis (and provide feedback). Obviously, students appreciate an in-depth reading, but it is common for committee members to focus on chapters closest to their expertise. Reading depths varies - some provide line edits, others just suggest larger issues that should be addressed ("Your related work section in Chapter 10 is a bit sparse and ends in 2005."). While this is probably not the place to suggest "do another year of research", filling in gaps is ok and I'd rather postpone a defense by a month if needed. Before the committee gets the thesis, I've done a first or sometimes second reading, but the whole point of the committee is to keep the advisor honest (and complement his or her knowledge or taste).
- Committee members attend the PhD defense, usually in person. Typically, this lasts about 90 minutes. Take notes on any editorial improvements (e.g., "make clear that the throughput graph is measured in gallons/minute"). Vote on the outcome and sign the form.
- If the student is given a set of changes to implement, the advisor asks students to detail on how they implemented the changes, similar to how an author may respond to reviewer comments for a journal. The committee informally signs off, or not, on these changes. There is no need to re-read the thesis.
Checklist for DissertationBefore you submit your draft to the committee, be sure to verify that you have done the following checks:
- Spell check;
- Check for missing chapter or figure references;
- Section, Chapter, Figure are capitalized;
- All references converted from  to [1,2,3];
- Consistent capitalization in captions;
- Verify expansion of all abbreviations at first instance;
- Avoid "tremendous", "huge" and other similar adjectives;
- End to end -> end-to-end;
- Check references for capitalization of abbreviations and missing data such as page numbers.
(Contributions by Ed Coffman, Jonathan Rosenberg and Sal Stolfo.)
[Hints for PhD proposal defenses] [Writing style] [Writing bugs]
"So long, and thanks for the Ph.D.!"
How to be a programmer
Last updated by Henning Schulzrinne
Well, I’m back. After 3 months of intense thesis writing, revisions, and successfully defending (all while working a part-time job in industry), I want to share with you Part 1 of 3 of this series. Part 2 will be how to finish your thesis in a timely manner (and write a good quality thesis). Part 3 will be life after a PhD, making the transition into the workforce, and how to prepare ahead of time (i.e. apply for jobs before, during, or after writing your thesis).
First, what does it take to give a successful PhD Defense? How can you prepare, keep the stress levels low, and make sure you have the highest chance of success?
I’ll just say that everyone’s PhD Defense is unique and is unpredictable. Your talk/presentation is only as good as you want it to be. And you cannot fully prepare for all the endless possibility of questions. If you wrote a 200 page thesis, your thesis commitee can pick apart an error bar on a graph on page 133. They can ask you what you meant by a word in a random sentence in any given paragraph. Keep in mind, this is all just apart of the PhD hazing process, and in a sense is just to humble you. At the end of the day, if you wrote a good quality thesis and are CONFIDENT, you should have no problem successfully defending and leaving that room with a sense of relief. Either way, I wanted to share my experience while it is still fresh in my mind
1) Do not underestimate how long it takes to prepare your slides/talk and make sure you give multiple practice talks
When I turned in my thesis two weeks ahead of time to my committee, I thought the hard part was over. Although a very important milestone, don’t let your guard down. If you already have most your slides ready to go, then you are lucky. I ended up getting data at the last minute and my story changed. I had to make many model slides from scratch.
If you want to give a GOOD thesis talk, you need to practice multiple times. And this means that you don’t cram it all in a couple of days right before your talk. I’m not talking about giving just one practice talk. You need to give multiple group practice talks. In between, you need to practice on your own.
You certainly don’t have to memorize every word of your thesis defense talk, but you should have it well-polished. There is no limit (or requirement) on how many practice talks you should give, but give as many talks as it takes until you feel like you are ready. If you are unsure of the quality of your talk (or being “ready”), tape record yourself or watch a video of yourself to see just how good it is. You might be surprised when you play it back to yourself.
You should also time your talk. I noticed that I tend to talk faster (by about 5 minutes) when giving the actual public talk vs. when I practice on my own. The length of the talk can depend on many departmental factors. My talk was ~45-50 minutes long which also leaves time for questions.
Either way, do not procrastinate on your slides and/or talk until days before. Make sure you use the full two weeks to perfect your slides, polish your talk (and be very concise about your words), and review material you are unsure about.
2) Listen to other thesis defense talks
The best way to mentally prepare for your thesis defense talk is to listen to other thesis defense talks. I actually went and got a few talks on DVD (the good ones that I remembered). If their research is on a similar topic as your own, this would be more ideal-but take what you can get. When you watch the talk, ask yourself what makes it good or bad? Were they enthusiastic and sincere? Did they keep the energy throughout the talk? Were there some rough areas of the talk? When nerves are running high, talks may not go as expected. You can battle this nervousness by showing up well-prepared. If you are, the thesis defense talk is just a formality.
If you cannot obtain any thesis defense talks on video, make sure that you go to actual public thesis defense talks. At least go to one so that you have a good idea of how to TIE the whole story together and give your audience the big picture. Keep in mind that you are giving a talk to a general audience. This means that use of jargon and highly technical terms will only put your audience to sleep. Make sure it is clear and understandable. Simplify it the best that you can and put it in the larger context of your research field. Use cartoons or model slides (if necessary) to give your audience the general, overall picture.
3) Have your friends, labmates, and others drill you with questions
What’s the best way to prepare for unforeseen questions? Have others that are familiar with your work drill you with questions. Chances are that even though these questions may not be the actual questions you will be asked either by the public and/or your thesis committee, it prepares you to think on your feet. It also builds your confidence. And the questions that your labmates or friends ask you may just be the same question you will get asked on your defense day.
4) Re-read over your entire thesis and write out your own list of questions
You may be sick of reading your entire thesis over and over by now, but you need to keep everything fresh in your mind. I actually read over my entire thesis multiple times during my final two weeks and came up with my own list of questions that I thought my committee would ask me. In addition, I also came up with a list of questions that I had of my own (questions that I was unsure of or that I thought were a weakness of mine). If you cannot come up with a list of good questions, then you are not trying hard enough.
Even though my committee didn’t ask me my exact list of questions, the process of coming up with my own list of questions-then finding the answers to those questions (beyond my thesis)-actually helped me gained a deeper understanding of my project. And it was a confidence booster in disguise.
5) Don’t let distractions get to you
Completing your thesis is a huge milestone. Those last two weeks until defense day can be stressful. Whether you are doing job interviews, applying to other jobs, or you want to “jump the gun” and finally start your post-PhD life, don’t give into temptation. Keep your guard up until your actual defense day. This is key to giving a good talk. You need to go in with the mindset that you will kill your presentation and give a long lasting impression to your audience. I have actually heard that some people who gave great thesis defense talks were offered a position shortly after (i.e. a postdoc).
You are going to want to do all those little tasks that you have been putting off for so long because you have spent X amount of months writing your thesis in solitude and you had no time to do them. Your list could be very long. I can tell you that one of the things on my list was to keep publishing blog articles and keep my blog running. I simply did not have enough time. Prioritize and focus on your defense talk and nothing else. If you are looking for jobs during this time period, I will be writing about this in Part 3 of this series.
6) Get plenty of sleep, keep your diet in check, and take care of yourself
This might be the most difficult thing for anyone. I struggled with this the most while writing my thesis. Skipping meals, late nights, overloading your system with caffeine just to stay awake. You have to fight it the best that you can. A month before my defense talk, I hit the gym 3x a week (for the first time in months). Everyone handles the anxiety of their defense talk differently. I am someone who thinks about it constantly. So it becomes hard to focus on other things, like taking care of yourself.
Once your thesis is turned in to your committee members, during those final two weeks- sleep and a proper diet are KEY. The day of your defense, make sure you are well-rested (don’t stay up all night stressing about it) and eat well. Don’t sell yourself short. By taking care of yourself, you ensure that you have the highest probability for giving a great thesis defense talk and showing your committee members that you are confident about your project.
7) Keep your cool and relax
When your defense day comes, you have to remember that you have put in a lot of HARD WORK to get to this point. You know your topic better than anyone. Because of this, you have no reason to be stressed out.
When your committee pushes you and asks you questions, they again will push you to your limits. You will meet a point where you won’t know the answer. Also, a question could simply be a future direction/experiment that you simply haven’t tested yet. Remember that they are simply trying to test your knowledge and humble you. You don’t have to know all the answers. Therefore, when you are answering questions, keep your cool and relax. Answer the questions the best that you can and you should have no problem passing. And in all honesty, the prelim (or qualifying exam) was much harder than the actual defense…
8) Don’t focus on the after-party until you have actually reached the after-party
Who doesn’t want to spend their final two weeks planning the celebration? Although I did have an after-party, I did not go to great efforts to plan it like a wedding party. As I said in #5, prioritize and focus on your thesis defense talk and nothing else. Plan your after-party while you are on break from your practice talk/preparing for questions/working on slides but do not make it a number one priority. Once you have passed, then you can change your focus. The feeling is indescribable (see #10).
9) Have a good structure
A good thesis talk also has a good introduction before going on to the next idea or slide. It should flow in a logical manner and be smooth. That is why #1 is important, because many people don’t spend enough time in the creation of good powerpoint slides. Your slides and talk have to MATCH up, meaning you can’t have really good slides and a mediocre talk (or vice versa) if you want it to go well.
This is why practice is important, and if you spend enough time on BOTH the talk/slides you will give a very good talk. A lot of times while I was actually practicing my talk, I had to go back and change the order/wording of slides or how I introduced certain slides (the wording) so that the flow would be better.
Be formal in how you word things (i.e. say “our data show that”… vs. “you see here that”…). To give a good introduction, it might be wise to use slides that ask a question in between. This question slide (break) in-between your next idea allows for your general audience to CATCH UP and understand your logic. Why are you doing this experiment? If you just show a bunch of your published data with no introduction (and maybe a title that gives an interpretation/punchline), you will overwhelm and bore your audience.
Many scientists forget that although they are an expert on their topic, what seems easy and understandable to them-does not apply to others outside of their field.
Before you go to your next data slides introduce the idea (based on this data I wanted to ask this question). Then tell them WHY you performed this particular experiment (which is basically in the form of a question). Once your audience understands why, go on to the next slide and give them your interpretation. In other words, don’t just jump to the interpretation. This will keep your audience’s attention and make sure that your thesis defense talk gets a lot of positive feedback and leaves a good impression on your committee members (it really does show).
10) Visualize yourself giving your defense each day and think about how good it will feel when it’s over
This one is pretty self explanatory. I will say that when it is all said and done, it feels like a huge burden has been lifted off your shoulders. It is emotional and you finally feel that all that hard work and time that you put in over the years-was all worth it in the end. Good luck to all those who are preparing for their defense talk in the future! Think about what it will be like to get up in front of a large audience and show everyone how you moved a field forward. This is YOUR moment to show everyone you are an expert in your field. The more you keep this mentality, the better your talk will be. Keep your cool and relax (#7) and everything will be fine.
If you would like to see an example video of a defense talk that illustrates the advice I’ve given, a link to my PhD defense can be found here: http://bit.ly/1sAIT7O
Best of luck to all!