Longitudinal measurement invariance of the Short Warwick-Edinburgh Mental Well-Being Scale (SWEMWBS) among adolescents in the Czech Republic

Abstract Background Monitoring adolescent mental well-being requires instruments that measure the construct consistently over time. Although the Short Warwick-Edinburgh Mental Well-Being Scale (SWEMWBS) has been widely validated across countries and diverse demographic, cultural and clinical groups, its longitudinal measurement invariance (LMI) has not yet been examined. Without evidence of invariance, observed changes in mental well-being may reflect measurement artefacts rather than true developmental trends. This study tested the LMI of the SWEMWBS among Czech adolescents across three annual waves. Methods Data were drawn from three waves (2023–2025) of the Czech Education Panel Survey (CZEPS), including 13,739 secondary school students who participated in all waves. Descriptive statistics and reliability coefficients (Cronbach’s alpha, McDonald’s omega) were calculated. Confirmatory factor analysis (CFA) with robust maximum likelihood estimation (MLR) was used to test the one-factor structure in each wave. LMI was assessed using multiple-group CFA (MGCFA) testing four levels of invariance: configural, metric, scalar, and strict. Model fit was evaluated using CFI, RMSEA, and SRMR, and changes in these indices between nested models were used to evaluate LMI. Latent mean differences across waves were also examined. Results The one-factor structure of the SWEMWBS demonstrated good model fit in all waves. Longitudinal analyses (MGCFA) supported full strict invariance, as changes in CFI, RMSEA, and SRMR between nested models remained below recommended thresholds. Comparison of latent means revealed a small but consistent increase in adolescent mental well-being from 2023 to 2025. Results based on arithmetic means showed a nearly identical pattern with the latent means from MGCFA. Conclusions The Czech version of the SWEMWBS demonstrates full strict invariance across three years of adolescence. The scale can therefore be used to assess developmental changes and monitor trends in Czech adolescent mental well-being over time with confidence.