Advice on studying for epidemiology and biostats preliminary exams
When I was studying for prelims, I spent some time searching for advice on how or what to study, or any tips and tricks from people who've taken these exams for epidemiology. I was pretty surprised not to find much out there, even though to the best of my knowledge most epi PhD programs have prelims of some description (mine were General Epidemiology, Biostatistics, and Applied Data Analysis after the first year of my program). Now that prelims are (thankfully!) behind me, I figured I'd write up a prelims guide of sorts in case it would be helpful for others.
Prelims were in mid-August, and I began studying in mid-May. Originally, I told myself I'd start studying by spring break (mid-March) at the latest, but of course that didn't happen given my course load and research. But starting in May was enough time, even though it didn't always feel like it would be. One of the first things I did (before the program provided us with a list of what would be on the exams) was go through syllabi for the relevant classes and figure out all the learning objectives to use as an initial framework. My cohort and I also started organizing a weekly study group (on Zoom, because this was during COVID). Around two weeks before the exams, I put together the double-sided cheat sheet we were allowed to have for the epi exam.
Reviewing class material:
We received the official list of testable material in mid-June, but I basically wound up reviewing everything anyway. This was fairly obviously inefficient. Although I could have been more efficient in what I chose to review, reviewing everything made me less anxious because it seemed way less likely they could throw something on the exam that I hadn't gone over. In the beginning, I also felt I had the time to give everything a solid once-over, and narrowed down my focus as we got closer to the exam. Material always sticks better in my brain when I write it out by hand, so that's what I started doing - going over all the class powerpoints and writing out notes. The downside is this is incredibly time consuming, and in all honesty I don't think I finished doing this for each class, but it was still a good way for me to get started especially when I didn't know what else to do. For the biostats exam, I went through all the lectures and created a massive flowchart of when to use each statistical test and how to interpret it. One upside of COVID is that lectures were recorded for around 25% of the total material that would be on prelims. I only rewatched the lectures where I felt I didn't quite understand the material, and didn't attempt to rewatch every lecture available, which I felt worked well for me.
I created a giant stack of pen to paper flashcards and initially committed to doing all of them every day. I also added to them as I went through lectures, old homeworks, and old exams.
However, the flashcards became unwieldy and hard to manage. I also realized I didn't want or need to do every question every day. That's when I started using Anki, which I originally learned about from my med student friends. It's an app where you can create your own flashcards and uses spaced repetition to determine when you will next see that card. The easier you rate a card, the longer the interval of time before you'll see it again. Anki gives you lots of great stats about your progress, including: daily average cards studied, passed reviews, average time spent per card, percent correct for new vs older cards, and intervals until reviews are shown again. Anki is incredibly flexible and customizable in terms of how you can set it up and what you can include in your deck (some helpful tips are located here and here).
I used the textbooks we had previously used in class, primarily the classic Gordis book and Epidemiology: Beyond the Basics. While I did read each book cover to cover, doing questions is highest yield. Gordis has an online supplement with many additional questions, though I thought they were poorly written compared to the questions in the book itself. Beyond textbooks, I spent a significant amount of time trying to find additional resources online. I didn't feel that the textbooks or redoing old homeworks/exams was sufficient practice to feel really confident, so I sought out those additional practice problems.
I flipped through the Gordis book so much the pages started to fall out
Unsurprisingly, practice problems are crucial. One of the professors on the prelims committee let us know that when she's met with students who failed, a frequent regret is that they spent too much time reading and not enough time doing practice problems. I tried to get the readings over with first to have a solid foundation fresh in my head before refocusing almost exclusively on practice problems. The most important problems to practice are whatever your department tells you to prioritize. In my case, that meant redoing old tests and assignments. Besides sitting down and doing them in sequence, I also added those questions to my Anki decks. It took awhile to do, but it was worth it. I was honest with myself about what concepts/types of problems I didn't have a truly solid handle on, which wasn't always a good feeling (I felt like I 'should' already know the material). After identifying those areas, I worked on going over those types of questions with others in my cohort - often someone else was able to explain it in a way that really helped. Alternatively, talking through concepts/working through a question with someone who didn't get it was really valuable for my own studying as well.
Time management and motivation:
By around July, I felt like I was using every waking minute to study. I also strongly suspected this could not possibly be the case. So I started using Toggl to track my actual study time. Toggl lets you categorize the time you spend, so I could determine how many hours I was spending on, say, biostats, and how much of that time was spent taking notes, doing practice problems, etc.
Here's a screenshot of how my study time broke down 2 weeks before prelims
Essentially, shortly before prelims I was averaging around 6 hours per day of study time (excluding work I was doing for class or research). I was definitely not using every waking minute to study, and it turned out fine anyway. I think it felt like every minute was dedicated to studying because of how anxious I was about the exams (it's quite possible that most of my waking minutes were dedicated to worrying about prelims). While I felt guilty spending time doing non-prelims related activities, it really is possible to take a walk or cook a new recipe without failing anything. Realistically, taking breaks for physical activity, nourishment, and giving yourself mental space to decompress are all part of what it takes to pass prelims while avoiding nervous breakdown. Most of my motivation to study was driven by fear of failing out of the program. Yet as I was studying, there were times I was glad I was going over some of the material, because otherwise it was unlikely I would have pushed myself to understand it.
Odds and ends:
When venting about prelims to people who had taken them already, I was often told 'oh you'll be fine!' This was never reassuring. Not everyone passes prelims and there was simply no guarantee that I would be one of them. Especially given the stakes, I think it's very reasonable to fear failure. By the time I took the exams, I simply wanted to get them over with. I'd done everything I could think of to prepare, even though I often told myself I should be pushing myself harder.
If you start studying early enough, are honest with yourself about what you don't know, and do all the practice problems you can find, you have set yourself up to pass. It's still no guarantee, but it's probably good enough - and that's all you need to put prelims behind you forever.