Psychometric properties of a new self-report measure of medical student stress using classic and modern test theory approaches.

BACKGROUND: Medical students face significant stressors related to the intense rigors of their training and education. Accurate measurement of their stress is important to quickly identify, characterize and ameliorate these challenges. Existing measures have limitations that modern measurement approaches, such as item response theory (IRT), are able to address. This study presents the calibration and validation of a new IRT-based measure called the Medical Student Stress Scale (MSSS). METHODS: Following rigorous measurement development procedures described elsewhere, the authors created and tested a pool of 35 items with 348 1st - 4th year medical students along with demographic and external validity measures. Psychometric analysis included exploratory and confirmatory factor analyses, IRT modeling, and correlations with legacy measures. RESULTS: Of the original 35 items, 22 were retained based on their ability to discriminate, provide meaningful information, and perform well against legacy measures. The MSSS differentiated stress scores between male and female students, as well as between year in school. CONCLUSION: Developed with input from medical students, the MSSS represents a student-centered measurement tool that provides precise, relevant information about stress and holds potential for screening and outcomes-related applications.