Development of a character qualities test for medical students in Korea using polytomous item response theory and factor analysis: a preliminary scale development study

PURPOSE: This study aimed to develop a test scale to measure the character qualities of medical students as a follow-up study on the 8 core character qualities revealed in a previous report. METHODS: In total, 160 preliminary items were developed to measure 8 core character qualities. Twenty questions were assigned to each quality, and a questionnaire survey was conducted among 856 students in 5 medical schools in Korea. Using the partial credit model, polytomous item response theory analysis was carried out to analyze the goodness-of-fit, followed by exploratory factor analysis. Finally, confirmatory factor and reliability analyses were conducted with the final selected items. RESULTS: The preliminary items for the 8 core character qualities were administered to the participants. Data from 767 students were included in the final analysis. Of the 160 preliminary items, 25 were removed by classical test theory analysis and 17 more by polytomous item response theory assessment. A total of 118 items and sub-factors were selected for exploratory factor analysis. Finally, 79 items were selected, and the validity and reliability were confirmed through confirmatory factor analysis and intra-item relevance analysis. CONCLUSION: The character qualities test scale developed through this study can be used to measure the character qualities corresponding to the educational goals and visions of individual medical schools in Korea. Furthermore, this measurement tool can serve as primary data for developing character qualities tools tailored to each medical school’s vision and educational goals.