Actually, the passing USMLE score for a successful US IMG was not substantially different from that of their unsuccessful peers. Those who matched had a mean Step 1 score of 217, unmatched: 204. Though they are both pretty low, the data does not support high stats being a defining characteristic of successful US IMG's. In my experience, really high stats are a red flag: why would someone capable of getting a score that high choose to go to the Caribbean (pretty scary). We don't interview Caribbean grads but if we did, both high and low scores would be exclusion criteria. Success for US IMG's
does seem more likely to be associated with a larger number of contiguous ranks. The more interviews you get, the more you can rank. To your point regarding AMG's, there were 56 US Seniors with Step 1 scores >241 that did not match in Ortho. Scores do not guarantee success for anyone in the very competitive specialties.
http://www.nrmp.org/wp-content/uploads/2014/09/Charting-Outcomes-2014-Final.pdf
http://www.ecfmg.org/resources/NRMP...atch-International-Medical-Graduates-2014.pdf