Validity of the Medical College Admission Test for Predicting Medical School Performance

PURPOSE: Since the introduction of the revised Medical College Admission Test (MCAT(R)) in 1991, the Association of American Medical Colleges has been investigating the extent to which MCAT scores supplement the power of undergraduate grade point averages (uGPAs) to predict success in medical school. This report is a comprehensive summary of the relationships between MCAT scores and (1) medical school grades, (2) United States Medical Licensing Examination (USMLE) Step scores, and (3) academic distinction or difficulty. METHOD: This study followed two cohorts from entrance to medical school through residency. Students from 14 medical schools' 1992 and 1993 entering classes provided data for predicting medical school grades and academic difficulty/distinction, while their peers from all of the U.S. medical schools were used to predict performance on USMLE Steps 1, 2, and 3. Regression analyses assessed the predictive power of combinations of uGPAs, MCAT scores, and undergraduate-institution selectivity. RESULTS: Grades were best predicted by a combination of MCAT scores and uGPAs, with MCAT scores providing a substantial increment over uGPAs. MCAT scores were better predictors of USMLE Step scores than were uGPAs, and the combination did little better than MCAT scores alone. The probability of experiencing academic difficulty or distinction tended to vary with MCAT scores. MCAT scores were strong predictors of scores for all three Step examinations, particularly Step 1. CONCLUSIONS: MCAT scores almost double the proportion of variance in medical school grades explained by uGPAs, and essentially replace the need for uGPAs in their impressive prediction of Step scores. The MCAT performs well as an indicator of academic preparation for medical school, independent of the school-specific handicaps of uGPAs.