For the past three years I’ve been doing a PhD at Aston University's Neuroscience department in collaboration with the Birmingham Children’s Hospital. I have been looking at the relationship between omega-3 and omega-6 fatty acids in the blood, brain metabolites detected with a neuroimaging technique called Magnetic Resonance Spectroscopy and cognitive ability. For those that are particularly interested, here’s a link to my thesis abstract. After two and a half years of planning and implementing the research, I spent the last three hellish months of 2010 writing the 65,000 words of my thesis and submitted in the first week of January. It’s been a couple of weeks since I passed my PhD viva exam and I can finally relive the agony and the ecstasy of the event.
Whilst preparing for my viva, I found that as well as differing between countries, the conventions of the viva differ according to the institution, the topic area, the type of thesis submitted and the examiners, therefore no two vivas are the same.
In the most general terms, the viva is there to establish that the thesis is the student’s own work. It’s an examination of how well they can defend the research, how it was conducted, what the findings are and what they mean, and whether the thesis makes a strong and original enough contribution to knowledge to be worthy of a PhD. In the UK, the viva is ‘closed’, so that only the examiners, and possibly your supervisor and an independent chairperson, are present. In some European countries, public defences, where anyone, including as the name suggests the general public, can attend your viva and ask questions, is more common. How the viva is conducted is completely up to your examiners, of which there are usually two: an internal examiner (from your own institution) and an external examiner (from another institution).
Having trawled through dozens of university advice websites and personal blogs, and attended some thesis and viva preparation workshops, here’s my collection of the best advice that I came across for preparing for your viva. I’ve split them up into different stages of preparation, but the lists themselves are in no particular order. I hope it helps current PhD students who have their vivas coming up.
Things you can do well in advance of your viva:
Read your university’s rules and regulations, that way you know exactly what to expect.
Attend courses or workshops on thesis and viva preparation. If they’re run by your university or department, they’ll be a great resource for institution-specific advice.
Be involved in all aspects of the work so that you can claim full ownership of it. Some decisions will, of course, be out of your hands, but you still need to know why those decisions were made, and if there were alternative choices, why they weren’t taken. I learnt this lesson the hard way in my year-one viva when asked to justify one technique over another. ‘Because my supervisor told me to’ just won’t cut it, even if at the initial stage it’s the honest answer.
Present your research at as many conferences/seminars/lab meetings as you can over the course of your PhD so that you are comfortable talking about your work in front of different audiences. The more you talk about your work and the more you have to defend it, the easier the viva becomes. A couple of tricky questions during my viva had already come up at conferences I had presented at and it helped that I had thought through the answers before.
Ask the people in your lab/office, especially those that have recently finished, for advice. Concentrate on how they prepared and the kinds of things they found most useful to do beforehand, rather than what their actual viva was like. I found that asking people about their viva was more confusing than useful, because each person had had a completely different experience. How other people’s vivas went is no indication of what will happen during yours.
Pick the right external examiner. Unless you’re spoiling for a fight, pick someone who is somewhat sympathetic to your approach and ideas. In my case, my research covered lipid analysis, neuroimaging and psychometric assessment with healthy and clinical paediatric populations. To save having a committee of examiners (which I think is against the rules anyway), my examiner, Professor Gary Green, was chosen for his broad knowledge of neuroscience and neuroimaging and his medical background, rather than any specific contributions to the particular fields my work covered.
Do a little research into your examiners’ backgrounds so you know exactly where they are coming from. Try to find out what kind of person they are as well as their research interests. How much you need to do this depends on how well you already know your examiner and how much you’ve cited their work in your thesis.
In the run-up to the viva:
The advice from one of the viva workshops I attended was to start preparing in earnest about six weeks in advance. Starting a new job immediately after submitting my thesis was actually a good thing, as it completely took my mind off my PhD. Having worked on the same topic for three years, it’s hard to really approach it with fresh eyes, but taking some time completely away from your thesis will allow you to put yourself in your examiners’ shoes. After having nearly six weeks away from something I stared at morning, noon and night for months on end I saw my work in a new way. Not only did I spot holes and mistakes, but I also understood it better as a whole.
Keep abreast of the literature. If something that has an important bearing on your work has been published between your submission and the viva, you need to know about it. I found a paper published a couple of months after I submitted which backed up some of the things I said in my thesis and I’m sure it won me some brownie points.
Take advantage of the fact that the viva is an open book exam. At the very least you should have an annotated copy of your thesis with you. Other people have also advised taking in your lab books in case your examiners wish to look at primary data.
Try to ‘revise’ from summaries and bullet-pointed lists, rather than the actual thesis. I found that working from summaries helped me think of the bigger picture, rather than getting unnecessarily fixated on specifics. I summarised my thesis in five broad categories, with four or five bullet points for each:
- What I did
- Why I did it
- How I did it
- What I found out
- What the findings mean and their implications
A great tip I picked up from Phillips and Pugh’s book was to create a table with two columns, one for page numbers and the other to summarise each page of the thesis in one line, with a couple of words per paragraph. This really helped me focus on the key points of everything I had written and proved really handy as a way of navigating around my thesis during the viva, in response to specific questions.
When going through my thesis page by page I created two sets of post-its. The first were major points or corrections for that particular page, and the second were for the chapter as a whole and summarised the key finding/conclusions, anything I thought might need qualifying or clarifying andany major points of contention.
Don’t try to anticipate your examiners’ exact questions. I tried doing that and pretty much not a single thing I thought they would ask came up. The questions can move from the very specific to the very general, often fairly quickly, and it’s better to be prepared for anything. Although I’ve already said that each viva is unique, these are some of the more generic questions I got asked:
- Talk us through your thesis – having spent so long working on the same thing, most people have their two-minute elevator speech worked out. Flesh it out to about five minutes and you’re on your way.
- How did this project come about/what was the motivation for doing this research?
- Why did you have this particular hypothesis?
- Why did you choose this method over this one?
- How did you make sure your results were reliable and valid?
- What are your main findings?
- What is the direct impact of your research?
- How/where are you going to disseminate your work?
There’s no escaping that pain in the researcher’s backside that are confounding variables. You’ll have no doubt been thinking of them as you were writing and doing your research, and they will have gone into your discussion, but unless you’re working in a closed, well defined system, you won’t have thought of them all. Confounds are the best and easiest way to test how robust your findings and arguments are, and if your viva is anything like mine, you’ll spend a good chunk of your time discussing them. I had already thought and written about some of confounds that might undermine my results and was asked to talk through them in more detail. Others came from left field and I really did have to think on my feet.
Don’t leave things to the last minute, do expect the unexpected. The week before my viva I was struck down with a really bad cold that completely messed up my preparations and then the night before my viva, plans for a final read-through my summaries were scuppered when I had to bury our beloved hamster (RIP in peace Earl Grey). You’re never going to feel 100% prepared (I certainly didn’t), but I try to make sure that it’s not for lack of time.
During the viva itself:
Don’t let the stack of post-it’s sticking out of the side of your examiner’s copy of your thesis put you off. As we talked we managed to cover a lot of his questions and skipped quite a lot of them.
Take your time to think – more than once I started talking and then realised I wasn’t really going anywhere.
Use all the notes and post-its you made to remind yourself of points and answers. There were a couple of times when my post-its reminded me of insightful things that I had already thought of, but that hadn’t occurred to me in the heat of the moment.
Unless it’s something basic and fundamental to your work, it’s ok to say ‘I don’t know’. For some questions my examiner pushed me for more and more detail until, short of guessing, I had nothing else to say. Your examiner can’t and won’t expect you to know everything, but they may try and find out exactly where the limits of your knowledge lie.
Ask for clarification if the question is not clear. Some of the questions I got asked were deliberately open and ambiguous, which left me with room to manoeuvre, and on at least one occasion I was asked a question where, until I asked my External examiner what he meant, I had no idea what he wanted.
Annotate your thesis as and when points arise. Although your examiners will give you a report of the corrections they would like made, I made notes of other things that came up during the discussion that will be important for publishing my work, but that are not necessarily important for the final submission of my thesis.
From what I can gather, most vivas are between two and four hours, and mine was over in three. Longer than four hours isn’t necessarily a bad thing, since lots of questions can mean that your examiner is really interested in your work (this happened to one of my colleagues – his viva lasted nearly six hours, but he passed with flying colours).
Take some time at the end, if you think both yourself and the examiners are up to it, to ask some questions. My viva was actually over after about two and a half hours, but once they were done I took the opportunity to ask my examiners some questions and ask for advice on turning my chapters into manuscripts for publication. This was great because my External advised splitting one of my chapter into two papers, one as a quantitative review and the other as original research. I also asked about which journals to target and to clarify one amendment that they asked me to make.
As perverse as this may sound (and I realise it’s always easier to say so in Dr-prefixed hindsight), I am glad I was given a hard time during my viva, because at the end of it I really felt like I had earned it and I can now put all that constructive criticism (however harsh it may sound at the time) to good use as I try to get my work published.
The decision to award the degree will be based partly on the quality of the thesis itself and partly on the performance in the viva. The very best preparation you can do for the viva is submit a thesis that you are happy with – it’s much easier to defend something you are proud of!