US Medical Student Performance on the NBME Subject Examination in Internal Medicine: Do Clerkship Sequence and Clerkship Length Matter?

BACKGROUND: Prior to graduation, US medical students are required to complete clinical clerkship rotations, most commonly in the specialty areas of family medicine, internal medicine, obstetrics and gynecology (ob/gyn), pediatrics, psychiatry, and surgery. Within a school, the sequence in which students complete these clerkships varies. In addition, the length of these rotations varies, both within a school for different clerkships and between schools for the same clerkship.

OBJECTIVE: The present study investigated the effects of clerkship sequence and length on performance on the National Board of Medical Examiner's subject examination in internal medicine.

PARTICIPANTS: The study sample included 16,091 students from 67 US Liaison Committee on Medical Education (LCME)-accredited medical schools who graduated in 2012 or 2013.

MAIN MEASURES: Student-level measures included first-attempt internal medicine subject examination scores, first-attempt USMLE Step 1 scores, and five dichotomous variables capturing whether or not students completed rotations in family medicine, ob/gyn, pediatrics, psychiatry, and surgery prior to taking the internal medicine rotation. School-level measures included clerkship length and average Step 1 score.

DESIGN: Multilevel models with students nested in schools were estimated with internal medicine subject examination scores as the dependent measure. Step 1 scores and the five dichotomous variables were treated as student-level predictors. Internal medicine clerkship length and average Step 1 score were used to predict school-to-school variation in average internal medicine subject examination scores.

KEY RESULTS: Completion of rotations in surgery, pediatrics and family medicine prior to taking the internal medicine examination significantly improved scores, with the largest benefit observed for surgery (coefficient = 1.58 points; p value < 0.01); completion of rotations in ob/gyn and psychiatry were unrelated to internal medicine subject examination performance. At the school level, longer internal medicine clerkships were associated with higher scores on the internal medicine examination (coefficient = 0.23 points/week; p value < 0.01).

CONCLUSIONS: The order in which students complete clinical clerkships and the length of the internal medicine clerkship are associated with their internal medicine subject examination scores. Findings may have implications for curriculum re-design.