Validity of four approaches of using repeaters' MCAT scores in medical school admissions to predict USMLE step 1 total scores

BACKGROUND: This study investigated the validity of four approaches (the average, most recent, highest-within-administration, and highest-across- administration approaches) of using repeaters' Medical College Admission Test (MCAT) scores to predict Step 1 scores. METHOD: Using the differential predication method, this study investigated the magnitude of differences in the expected Step 1 total scores between MCAT nonrepeaters and three repeater groups (two-time, three-time, and four-time test takers) for the four scoring approaches. RESULTS: For the average score approach, matriculants with the same MCAT average are expected to achieve similar Step 1 total scores regardless of whether the individual attempted the MCAT exam one or multiple times. For the other three approaches, repeaters are expected to achieve lower Step 1 scores than nonrepeaters; for a given MCAT score, as the number of attempts increases, the expected Step 1 decreases. The effect was strongest for the highest-across-administration approach, followed by the highest-within- administration approach, and then the most recent approach. CONCLUSIONS: Using the average score is the best approach for considering repeaters' MCAT scores in medical school admission decisions.