Factors Influencing NBME Surgical Shelf Exam Scores: A Systematic Review

Abstract

Introduction: There are multiple factors that can impact a student’s success in a surgical clerkship, including preclinical curriculum and grades, previously completed clerkships, clerkship sequence and schedule, length of clerkship, work-study balance, and quality of education during the clerkship. These factors make it difficult for medical educators to assess the effectiveness of their preclinical and clinical curricula. This is the first systematic review to date that has analyzed the factors that negatively or positively influence NBME Surgery Subject Exam scores. Methods: Computer systematic literature searches of the Embase and Pubmed databases were performed. The studies included in this systematic review were papers testing variables that affect NBME subject exam performance of medical students in their third-year surgical clerkships. Results: The literature search resulted in 2,823 articles, of which 17 were selected for analysis. The studies included in this review were grouped into three categories based on variables assessed: preclinical factors, third-year clerkship scheduling or structure, and surgical clerkship educational methods. Analysis shows that the quality of medical students’ preclinical education plays a strong factor, as USMLE Step 1 scores and second-year NBME scores have a strong positive correlation with exam scores, while shortened preclinical curricula negatively impact third-year NBME exam scores. While the length of the surgery clerkship has varied significance based on multiple studies, the sequence of clerkships showed a consistent correlation with third-year NBME exam scores. Taking medicine clerkship prior to the surgery clerkship showed significant improvement in third-year NBME exam scores across multiple studies. The quality of clinical education received at clerkships is also very important; multiple studies of different educational models have shown that increased student engagement through presentations, small-group case-based learning, and direct resident interaction resulted in increased test scores. Additionally, the student-perceived educational quality along with preceptor-perceived clinical competency via clerkship evaluations and OSCE are positively correlated with NBME subject exam scores. Conclusion: This systematic review looked at multiple factors that influence student success of the NBME Surgery Subject Examination and should be a useful tool for medical educators and students looking to increase NBME Surgery Subject Examination grades at their institution.