Psychometric Evaluation of the Persian Positive Youth Development Very Short Form among Iranian Adolescents: Evidence from Confirmatory Factor and Bifactor Modeling

The Positive Youth Development–Very Short Form (PYD-VSF) is a brief measure of the Five Cs of positive youth development; however, its measurement properties have not been evaluated among Persian-speaking adolescents. This cross-sectional psychometric study examined the structural validity, reliability, measurement invariance, and external construct validity of the Persian PYD-VSF in a school-based adolescent sample. Participants were 740 Iranian adolescents aged 13–18 years (M = 15.01, SD = 1.57). The PYD-VSF was translated using forward–backward translation, expert review, and cognitive pretesting. Structural validity was evaluated using confirmatory factor analysis and bifactor modeling with the weighted least squares mean- and variance-adjusted estimator. Reliability was examined using Cronbach’s alpha, McDonald’s omega (ω), composite reliability, omega hierarchical, and test–retest intraclass correlation coefficients. Measurement invariance across gender and developmental stage was tested using multi-group confirmatory factor analysis. The bifactor model showed slightly better fit than the correlated five-factor model (CFI = 0.99, TLI = 0.99, RMSEA = 0.03, SRMR = 0.02). Items loaded substantially on the general PYD factor (λ = 0.49–0.63). Omega hierarchical (ωh = 0.78) supported the interpretability of the total score, whereas explained common variance (ECV = 0.46) and omega hierarchical subscale coefficients (ωhs = 0.36–0.51) indicated meaningful but comparatively attenuated domain-specific variance. Internal consistency (α = 0.91, ω = 0.89), test–retest reliability (ICC(2,1) = 0.78, 95