Development of an assessment technique for basic science retention using the NBME subject exam data

One of the challenges in medical education is effectively assessing basic science knowledge retention. National Board of Medical Examiners (NBME) clerkship subject exam performance is reflective of the basic science knowledge accrued during preclinical education. The aim of this study was to determine if students' retention of basic science knowledge during the clerkship years can be analyzed using a cognitive diagnostic assessment (CDA) of the NBME subject exam data.

We acquired a customized NBME item analysis report of our institution's pediatric clerkship subject exams for the period of 2017-2020 and developed a question-by-content Q-matrix by identifying skills necessary to master content. As a pilot study, students' content mastery in 12 major basic science content areas was analyzed using a CDA model called DINA (deterministic input, noisy "and" gate).

The results allowed us to identify strong and weak basic science content areas for students in the pediatric clerkship. For example: "Reproductive systems" and "Skin and subcutaneous tissue" showed a student mastery of 83.8 ± 2.2% and 60.7 ± 3.2%, respectively.

Our pilot study demonstrates how this new technique can be applicable in quantitatively measuring students' basic science knowledge retention during any clerkship. Combined data from all the clerkships will allow comparisons of specific content areas and identification of individual variations between different clerkships. In addition, the same technique can be used to analyze internal assessments thereby creating an opportunity for the longitudinal tracking of student performances. Detailed analyses like this can guide specific curricular changes and drive continuous quality improvement in the undergraduate medical school curriculum.