I think for a physics PhD at UMD you are required to take like ~4 classes and pass a couple of tests. The real point of a PhD is to have a mentor/advisor and be trained in how to do research, preferably to the point where you can begin to initiate yourself (although a lot of PhDs aren't good at this). The skills involved have nothing to do with how well you are at classes or what your IQ is. It is a much better measurement of your future success... by putting you in a 1-1 relationship with a mentor/advisor and asking you to produce. JM (I and most UMD students take far more than 4 classes. I think I took 15 or something, and I would have taken far more if I hadn't had problems. The classes that I did take, even the ones I was serious about, were not of great importance.)