Evaluating the construct validity of the health promotion literacy scale

Introduction: The development of a Health Promotion Literacy Scale within the USR Curriculum is crucial for addressing the existing gap in measuring the impact of USR on students’ citizenship and social engagement. This study aimed to develop and assess the psychometric properties of the Health Promotion Literacy-based Scale in USR (HPLS-USR) scale on medical university students through confirmatory factor analysis (CFA) in Taiwan. Methods: We conducted a cross-sectional study and recruited a convenience sample of 405 students in central Taiwan. The HPLS-USR scale, developed by Hung et al. in 2022, comprises four factors—personal growth, responsibility of citizenship, social interaction, and intellectual development—that together accounted for 61.83% of the total variance. Data analysis was performed using SPSS version 26 and AMOS (version 22.0) to perform a CFA to verify the model’s goodness of fit. Results: The modified model derived 17 items in 3 factors, with 51.02% of the total variance explained. The structural equation model displayed a good fit, suggesting that personal growth, responsibility for citizenship, and social interaction were latent variables of the Health Promotion Literacy-based Scale on a USR curriculum. The Cronbach’s alphas for the overall scale and the three subscales ranged from 0.82 to 0.93. The psychometric properties of the scale demonstrated good to excellent model fit in the CMIN/DF (χ2/df) = 3.149, GFI = 0.91, AGFI = 0.88, SRMR = 0.04, RMSEA = 0.07, NFI = 0.90, NNFI = 0.92, RFI = 0.89, IFI = 0.93, CFI = 0.93, PNFI = 0.78, and PCFI = 0.81. The Cronbach’s alphas ranged between.81 and.89; the composite alphas ranged between.87 and.94. Conclusion: This study provides preliminary construct validity evidence for the HPLS-USR scale, a robust and psychometrically sound instrument for assessing health promotion literacy among USR students.