unfortunately, you're thinking too rationally then.
great at equalizing great standardized test takers and those with privileged socioeconomic backgrounds into the accept pile by giving adcoms another number that has the potential to be interpreted as meaningful under a very selective context (step 1 correlations are shoddy).
http://fairtest.org/healthy-medical-school-admissions
"One research study showed that as a student progresses through medical school the power of the pre-admission interview ratings to predict medical school grade point average (GPA) generally increases over time while the power of MCAT scores decreases.2 Another study considered the effects of MCAT scores and "non-cognitive" measures on basic science grades and clinical competence in medical school. While only 4% of the variation in the ratings of clinical competence were related to MCAT scores, 14% could be explained by psycho-social measures.3 While no one factor contributes greatly to predicting success, test scores are clearly only weak predictors whose value decreases as students progress through training."
more viable info than the horrifically shoddy correlation with the step 1 that's frequently claimed.
It gets even better:
" 20% of whom as part of their "special consideration" status did not need to meet MCAT and GPA minimums - had graduation rates and performance reviews in residencies that were "remarkably similar" to students admitted under standard criteria."
Nothing like being evaluated on a metric that is just there for the sake of being an easy way to supposedly rank people and demonstrates very little.