Using the Clerkship Shelf Exam Score as a Qualification for an Overall Clerkship Grade of Honors: A Valid Practice or Unfair to Students?

Most clerkships require medical students to pass the National Board of Medical Examiners (NBME) subject (shelf) exam to pass the clerkship. Many use the NBME's recommended honors cut score on the shelf exam to determine medical student eligibility for an overall clerkship grade of honors. This use of a conjunctive scoring model for determining honors is inconsistent with the logic behind the intended use of this model for making pass-fail determinations. Further, many clerkships use grading systems that employ both this conjunctive model for honors eligibility and a compensatory scoring model for determining the overall clerkship grade. For students who fall short of the shelf exam honors cut score, such a grading system effectively increases the weighting of shelf exam performance and decreases the clerkship's transparency about the weighting of performance on other assessments toward the clerkship composite score and overall grade. It may also lead to contradictory grading results in which student B has a higher composite score than student A, yet student B receives a lower overall grade. The author illustrates how to calculate a weight for shelf exam performance that would be fairer to students and would help create a more transparent weighting scheme for the grading system. The author recommends that clerkships restructure their grading systems so that shelf exam honors-eligibility cut scores are not used as conjunctive criteria for determining overall clerkship grades of honors. A reexamination of the NBME's practice of suggesting honors-eligibility cut scores for shelf exams is also recommended.