If you generally score above the class average in medical school (not by a large margin, but above anyway), what are the chances that you will get a good score? Or what are the chances you will bomb the thing?
I also thought of this when looking at my class schedule: are the boards of each subject reflective of what will be tested on the Step I? At the very least, can the boards be used as a predictor of how well we are prepared for that subject for the StepI?
They tell us at our school that 80% on our exams (70% is pass) correlates pretty well to a 220. That being said, each person is different. Some do standardized tests better, some have extreme stress, some just run into a large string of questions in areas they are weak in.
There are no specific correlations between grades in subjects and USMLE Scores. That being said, most people who do well in their coursework and prepare well for USMLE, will perform well on the test. I have seen a few people who had a string of honors fail USMLE Step I and others who conditionally passed Gross Anatomy or biochemistry blow Step I out of the park and thus, there are exceptions to everything.
Step I is very integrated and is not tested by subject matter though some subjects are better represented than others. Path, Pharm and Physio are well represented with Gross Anatomy/Cell Bio not so well represented. You are actually asked to apply your basic science (pre clinical science) knowledge to some clinical situations.
Good solid review and thorough mastery of your coursework is your best strategy for preparation for USMLE (all steps). You can't sit and memorize board review books and expect to do well. More than one person with string of honors mentioned above is quite adept at memorization but not so adept at application.
When you are done with your pre-clinical coursework, you are in a good position to do your review. In the course of your review, you should do plenty of questions (such as Q-Bank/USMLEWorld) and have a good source for refreshing your knowledge base such as BRS Pathology etc. Your question source should guide your review in the sense that if you are missing tons of questions in Physio, you might need to spend some time in a physio review book.
Trying to remember or memorize "everything" is not going to work very well because you will burn up most of your time trying to keep random facts in your head when you don't need to and take away valuable time from practicing application of those facts to problems.
The worst thing that you can do is sit back and believe that just because you have excellent grades in your coursework, you are a "lock" for "acing" Step I. I did very well in my coursework and I left nothing to chance with Step I. I was also required to take Step I early (because of a medical school fellowship) which meant that I was the most efficient reviewer on the planet at the end of year 2 and had to be ready in 3 weeks to take that test.
