Exam Sequence and Timing as Predictors of COMLEX-USA and USMLE Performance in Osteopathic Medical Students

This study examined the impact of exam sequence and timing on the performance of osteopathic medical students on the COMLEX-USA Level 1 and Level 2 and USMLE Step 1 and Step 2 examinations. Two cohorts were analyzed: 364 osteopathic medical students who completed both COMLEX-USA Level 1 and USMLE Step 1 between 2020 and 2022 (prior to the implementation of pass/fail grading), and 734 osteopathic medical students who completed both COMLEX-USA Level 2 and USMLE Step 2 between 2021 and 2025. Student performance was evaluated based on the sequence of examinations and intervals between them. Because the scores did not follow a normal distribution, as indicated by the Shapiro-Wilk test, the Mann-Whitney U-test was employed to compare the median scores between the groups. Osteopathic medical students who undertook the USMLE examinations first consistently achieved higher scores than those who undertook the COMLEX-USA examinations first across most academic quartiles. Shorter exam intervals (1-7 days) were associated with higher scores, whereas longer intervals (≥8 days) were correlated with significantly lower scores. The effects of exam order and timing varied across performance quartiles, with lower-performing students deriving the greatest benefit from taking the USMLE examinations first and maintaining shorter intervals between the exams. Strategic scheduling of exams may enhance performance on both the COMLEX-USA and USMLE examinations, particularly for lower-performing students. However, individual factors should be considered when implementing these strategies. These findings offer valuable insights for osteopathic medical students and educators in planning exam preparation and scheduling.