Score Gains on the NBME Subject Examinations in Internal Medicine Among Clerkship Students: a Two-Year Longitudinal...

The impact of clinical proficiency on individual student scores on the National Board of Medical Examiners (NBME) Subject Examinations remains uncertain. We hypothesised that increasing the length of time spent in a clinical environment would augment students' performance.

Performance on the NBME Subject Examination in Internal Medicine (NBME-IM) of three student cohorts was observed longitudinally. Scores at the end of two unique internal medicine clerkships held at the third and fourth years were compared. The score differences between the two administrations were compared using paired t-tests, and the effect size was measured using Cohen's d. Moreover, linear regression was used to assess the correlation between the NBME-IM score gains and performance on a pre-clinical Comprehensive Basic Science Examination (CBSE). A two-tailed p-value <0.05 was considered significant.

Of the 236 students enrolled during the third year, age, gender, CBSE, and NBME-IM scores were similar across all cohorts. The normalised score gain on the NBME-IM at the fourth year was 9.5% (range -38 to +45%) with a Cohen's d of 0.47. However, a larger effect size with a Cohen's d value of 0.96 was observed among poorly scoring students. Performance on the CBSE was a significant predictor of score gain on the NBME-IM (R 0.51, R ² 0.26, p-value < 0.001).

Despite the increased length of clinical exposure, modest improvement in students' performance on repeated NBME-IM examination was observed. Medical educators need to reconsider how the NBME-IM is used in clerkship assessments.