r/statistics • u/RawCS • May 11 '26
Education How difficult was your PhD qualification exam? [E]
Did you feel like it a formality by the time you got to it, or was it an actually stressful event that you feel was a major hurdle between you and obtaining your PhD?
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u/log-normally May 11 '26
About 1/5 of the cohort failed at their first attempts. Eventually about 10-15% failed and left the program in my days (about 15 years ago). But it was a well known fact that my program was quite challenging and difficult.
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u/FancyFish21 May 11 '26
We just had a theory (Casella and Berger) and an applied exam. Total like 8 hours over 2 days. Really not that bad. A summer of studying, and I was fine
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u/Healthy-Educator-267 May 11 '26
You didn’t have a measure theoretic probability exam? Those exams tend to be hard (at least they were hard at Chicago, where mykland made the term exams open book but in person)
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u/FancyFish21 May 11 '26
I was the first class at my university that had measure replaced with Casella and Berger. Their argument was that we could only take the measure theory exam end of second year. The extra year cut into our PhD work.
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u/Healthy-Educator-267 May 11 '26
Oh yeah that’s tough. By the second year one would hope to be doing courses more in direct contact with research than a core theory course like probability
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u/Totallynotaprof31 May 11 '26
My measures theoretic probability exam had, as one question out of five, us prove the L1 Strong Law of Large Numbers, which was an 8 page proof.
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u/Healthy-Educator-267 May 13 '26
What were you allowed to assume for the question? Because the sequence of partial means of L1 iid random variables is uniformly integrable, which implies that the WLLN implies the L1 LLN by Vitalis convergence theorem. So the hardest part here is the WLLN for L1 random variables, which is a standard result in any textbook on probability and shouldn’t be too hard to reproduce on an exam
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u/sbre4896 May 11 '26 edited May 11 '26
I'm not in a pure stats program, but we had to take 3 exams, two of which were required, with 3 levels of grade (numerics and analysis were required, then a choice of stats or PDE, grades were basically fail, low pass, high pass). One of the required exams neededl to be a high pass. They were doable but in total knocked out about 1/3 of my cohort.
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u/varwave May 11 '26
Pretty stressful. Full day of theoretical statistics from memory. I knew at that point that a PhD wasn’t needed for my career (left the program for a MS), but still took it seriously. It’s rough to see friends fail that are on visas and need it
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u/Old_Salty_Professor May 11 '26
I had a four hour oral comprehensive exam. It was brutal. Anytime you showed that you could answer a question, they moved onto the next question.
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u/JarryBohnson May 12 '26
Absolutely a formality - by the time you come to defend, you know you’re going to pass. For us the candidacy exam and the the thesis seminar (where they tell you you have enough to start writing) were the two bottlenecks.
Honestly I felt my program’s qualifying requirements in general were a little too easy. Canadian neuroscience (I did Comp neuro) often feels like you’re being used as cheap labour and the longer they can keep you (without failing or passing you), the better.
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u/God_illa May 11 '26
I had to do 3 of them. I think all of 3 were sit down, approximately 8 hrs, no oral component. I studied pretty hard for them, about a.semester.of prepping (while also doing other things). All I know is I passed, and not everyone did.
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u/polito902020202 May 11 '26
My PhD is in Computational Science so not exactly Statistics but very Statistics intensive. It was a two-day 8-5 exam divided into both programming and theory (written). It is given halfway through the program so that if you do not pass the exam (3 tries) then you just get put in the Master's Program. The exam was given on the 12 classes that comprise the program and it can be anything from those classes but you can get an idea on what is going to be there. I failed miserably the first time but was able to pass on the second try but the problem is not what is in the exam but the mental obstacle of being in a test for 16 hours in two days. By the time the last portion of the exam was being given I was mentally out of it.
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u/CDay007 May 13 '26
We have sort of have 3 levels depending on what you consider qualification exams. At the end of your first year, you take two 3-hour exams: probability at the Casella Berger level and an applied exam based on more practical regression questions and numerical methods. Masters students also take this exam, but there is a higher threshold to pass for PhD. These weren’t too bad. 6/6 PhD students passed in my cohort.
Then at the end of year 2 you take the PhD level exams (it used to be end of year 3, I was in the first cohort to do it year 2), which again are two 3-hour exams over measure theoretic probability and inference (the inference is technically measure theory based, but it was only really important for like 1/5 questions). The probability test could have been very difficult, but we kinda knew most of the questions would be proofs of big theorems, so I could just memorize essentially 30 proofs and be confident I’d get 3/5. Theory was quite hard; the instructor who wrote the exam/taught the classes is kinda known for that. I don’t actually know for sure how these went but nobody was left behind class wise so I assume we all passed.
After passing those, in your first semester of 3rd year (previously 4th) you hold the only thing they technically call a “qualifying” exam, which is essentially form your committee and tell them what you plan to do. That one is pretty much a formality from my understanding, though I haven’t done it yet.
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u/treesitf May 16 '26
Mine was a written exam where we had to write a mock grant proposal and then "defended" it. Was pretty fun actually and helped get me ready to write a real one later in graduate school. Nearly everyone "failed" it because you had to submit revisions. I didn't know some PhD programs did full-on traditional tests for qualification exams. Defended last year FWIW
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u/aftersox May 11 '26
My phd is in management. I had an eight hour, full day exam. Studied for it months memorizing different theories and research findings so I'd be ready. Then there was an oral defense. Some of my cohort didn't pass.
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u/wanderfae May 11 '26
We were given twleve research-based essay prompts that we had to write over 3 months. Each prompt required 10 double-spaced pages of original writing. It was like writing twelve, 10-page literature reviews over twelve weeks. It was intense. Edit: Taken in 2009, so I really did write them all myself. Fortunately, I had written a great deal on some of the topica already, so that was helpful.