Classification tree summary of factors predictive of matching for (A) first attempt applicants (n = 1,690). The resulting decision tree explains 14% of the variability in probability of matching (5-fold cross-validation R2= 0.14). (B) second or higher attempt applicants (n = 233). The resulting decision tree explains 14% of the variability in probability of matching (5-fold cross-validation R2= 0.14). Green, high probability of matching (>0.8); NPA, number of program applications; P, predicted probability of matching; Red, low probability of matching (<0.4); USMLE, United States Medical Licensing Examination; Yellow, moderate probability of matching (0.4–0.8).