A Brief Report of Psychometric Evaluation of the SWEMWBS in Adolescents across 7 Countries: Using MGCFA and IRT

Objective:This study evaluates the psychometric properties of the Short Warwick–Edinburgh Mental Wellbeing Scale (SWEMWBS) among adolescents from seven culturally and linguistically diverse countries.Method:A total of 4,006 adolescents (ages 11–18) from 18 schools across Bahrain, Canada, Germany, India, Sweden, Turkey, and the United Arab Emirates completed the SWEMWBS as part of a school-based wellbeing survey. Participants responded in either English (n = 3,358) or French (n = 648). We examined internal consistency (Cronbach’s α and McDonald’s ω), conducted confirmatory factor analysis (CFA) to test unidimensionality, evaluated cross-national measurement invariance using multi-group CFA (MGCFA), and applied Item Response Theory (IRT) analyses to assess item discrimination, response thresholds, and measurement precision.Results:The SWEMWBS demonstrated acceptable-to-good internal consistency across all countries (α = .76–.82; ω = .76–.83) and a unidimensional structure with strong model fit (CFI = .983, RMSEA = .065). Full scalar invariance was supported across countries. IRT analyses showed that items 2 ("feeling useful") and 5 ("thinking clearly") offered the highest information, while country-specific patterns suggested subtle differences in item functioning. The test was most informative for adolescents with low-to-average mental wellbeing (θ ≈ −2.5 to +1.5). Intra-class correlation (ICC) indicated minimal school-level clustering (ICC = 0.037).Conclusion:Findings support the SWEMWBS as a reliable, unidimensional, and cross-culturally valid measure of adolescent mental wellbeing. These results provide psychometric justification for its use in global adolescent health research.