I think you need to get >50% to pass, it's probably 60something percent. If you don't suck at standardized tests, and did decent on USMLE and your in service exams, you are very likely to pass on 1st try. Study with either Medstudy or MKSAP and you should be fine. I found the test to be based mostly on rote memorization...I did worse than on USMLE because I honestly didn't want to memorize quite all of the minutiae on the IM boards and I knew what I needed to do to pass. If you are a bad test taker then you know it by now, and better study hard. Even if you are a good test taker, you need to study some just to avoid the possibility of failing. People who fail probably either didn't study at all, or were the ones who were marginal on the steps and in service exam as well. You can bomb some sections(s) and still do OK on the overall test. Only the bottom 10% or so fail.