Measuring medical student wellbeing longitudinally: a psychometric systematic review of commonly used scales.

BACKGROUND: Longitudinal measurements of medical student wellbeing are needed to evaluate the impacts of training and potential interventions, but the psychometric evidence underlying commonly used wellbeing scales is unclear, impairing selection decisions. We therefore synthesized the psychometric evidence of the most common scales employed to measure self-reported medical student wellbeing longitudinally. METHODS: We conducted a psychometric systematic review based on the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guidelines. We searched seven databases and gray literature in March 2023 for psychometric studies in medical students of 53 scales. Two independent reviewers completed screening and data extraction and resolved conflicts via discussion. We assessed study quality and psychometrics using COSMIN methodology and pooled results for internal consistency and test-retest reliability when there were ≥2 studies per scale. RESULTS: Of 2374 abstracts, we included 133 studies. Over a quarter (26.4%) of study scales lacked psychometric evidence in medical students. Internal consistency was the most studied property (118 studies), while there were no studies on measurement error. There was sufficient evidence of internal consistency for 30 scales and construct validity for 34 scales. However, there were only 1-6 scales with sufficient evidence for each of the remaining properties. Study quality varied widely and only 20 of them reported participant ethno-racial identity. CONCLUSIONS: Many scales commonly used to measure medical student wellbeing longitudinally lack medical student-specific psychometric evidence. Among those that do, few have any evidence beyond internal consistency and construct validity. Future psychometric studies are needed in diverse populations to better inform scale selection.