The Relationship Between US Medical Licensing Examination Step Scores and ABR Core Examination Outcome and Performance: A Multi-institutional Study

Abstract

Purpose: We analyzed multi-institutional data to understand the relationship of US Medical Licensing Examination (USMLE) Step scores to ABR Core examination performance to identify Step score tiers that stratify radiology residents into different Core performance groups.

Methods: We collected USMLE Step scores and ABR Core examination outcomes and scores for anonymized residents from 13 different diagnostic radiology residency programs taking the ABR Core examination between 2013 and 2019. USMLE scores were grouped into noniles using z scores and then aggregated into three tiers based on similar Core examination pass-or-fail outcomes. Core performance was grouped using standard deviation from the mean and then measured by the percent of residents with scores below the mean. Differences between Step tiers for Core outcome and Core performance were statistically evaluated (P < .05 considered significant).

Results: Differences in Step 1 terciles Core failure rates (45.9%, 11.9%, and 3.0%, from lowest to highest Step tiers; n = 416) and below-mean Core performance (83.8%, 54.1%, and 21.1%, respectively; n = 402) were significant. Differences in Step 2 groups Core failure rates (30.0%, 10.6%, and 2.0%, from lowest to highest Step tiers; n = 387) and below-mean Core performance (80.0%, 43.7%, and 14.0%, respectively; n = 380) were significant. Step 2 results modified Core outcome and performance predictions for residents in Step 1 terciles of varying statistical significance.

Conclusions: Tiered scoring of USMLE Step results has value in predicting radiology resident performance on the ABR Core examination; effective stratification of radiology resident applicants can be done without reporting numerical Step scores.

Keywords: ABR Core examination; USMLE Step score; predictors; radiology residency.