Comparing the cut score for the borderline group method and borderline regression method with norm-referenced standard setting in an objective structured clinical examination in medical school in Korea

PURPOSE: Setting standards is critical in health professions. However, appropriate standard setting methods do not always apply to the set cut score in performance assessment. The aim of this study was to compare the cut score when the standard setting is changed from the norm-referenced method to the borderline group method (BGM) and borderline regression method (BRM) in an objective structured clinical examination (OSCE) in medical school. METHODS: This was an explorative study to model the implementation of the BGM and BRM. A total of 107 fourth-year medical students attended the OSCE at 7 stations for encountering standardized patients (SPs) and at 1 station for performing skills on a manikin on July 15th, 2021. Thirty-two physician examiners evaluated the performance by completing a checklist and global rating scales. RESULTS: The cut score of the norm-referenced method was lower than that of the BGM (P<0.01) and BRM (P<0.02). There was no significant difference in the cut score between the BGM and BRM (P=0.40). The station with the highest standard deviation and the highest proportion of the borderline group showed the largest cut score difference in standard setting methods. CONCLUSION: Prefixed cut scores by the norm-referenced method without considering station contents or examinee performance can vary due to station difficulty and content, affecting the appropriateness of standard setting decisions. If there is an adequate consensus on the criteria for the borderline group, standard setting with the BRM could be applied as a practical and defensible method to determine the cut score for OSCE.