<p>I agree that a HS student should not concern him/herself with residency. Most HS students thinking of Medicine never make it or end up interested in doing something else. Being accepted to a US allopathic medical school is really the first criteria in trying to become a surgeon. While I do not think general surgery is all that competitive, the surgical subs are competitive as are derm, ophtho, rad onc, and rads. Criteria for matching varies from specialty to specialty and can be somewhat different between programs within a specialty.
A recent paper on dermatology for example found that AOA, medical school research rank, USLME scores, and number of unpublished manuscripts were significantly associated with matching. MSTP also probably helps. I suspect interview performance is also very important. An older paper on surgical matching found AOA, USLME, research experience and graduation from a top 40 NIH funded medical school to be positively associated with matching.</p>