The USMLE is like any other standardized test. Your percentile is derived from your score compared to everyone who takes the exam. For example, a score of 215 on step 1 of the USMLE means that you would fall in the 50th percentile, which makes that an average score. The nbme stopped submitting the percentile rank along with your 3 didit score to discourage residency programs from using it to weed people out based primarily on how well you did. They still give a 2 digit score but it does not correlate with your percentile rank. For example, if you score a 245 they will give you a 2 digit score of 99. However, your percentile would be in the low 90s. This makes the 2 digit score useless IMO because whether you 245 or 255 your 2 digit score will be 99. I know that all this is confusing but thats the way the show runs.