Factorial invariance of the PedsQL™ 4.0 generic core scales child self-report across gender: A multigroup confirmatory factor analysis with 11,356 children ages 5 to 18

The measurement of health-related quality of life (HRQOL) in pediatric medicine and health services research has grown significantly over the past decade. The paradigm shift toward patient-reported outcomes (PROs) in clinical trials and population studies has provided the opportunity to emphasize the value and critical need for pediatric patient self-report. In order for HRQOL/PRO outcome comparisons to be meaningful for gender group analyses, it is essential to demonstrate the factorial invariance of an instrument. This study examined factorial invariance of the 23-item PedsQL™ 4.0 Generic Core Scales across gender groups for child self-report ages 5-18. Multigroup Confirmatory Factor Analysis (MGCFA) was performed specifying a five-factor model across gender groups. The analyses were based on 11,356 children recruited from clinic, school, and community populations. Strict factorial invariance across gender groups was demonstrated based on stability of the Comparative Fit Index (CFI) between the models, and indices of practical fit including the Root Mean Squared Error of Approximation (RMSEA), the Non-Normed Fit Index (NNFI), and the Parsimony Normed Fit Index (PNFI). The findings support an equivalent five-factor structure on the PedsQL™ 4.0 Generic Core Scales across gender groups. Based on these data, it can be concluded that boys and girls studied interpreted items on the PedsQL™ 4.0 Generic Core Scales in a similar manner. These findings have implications for studies of gender differences in health outcomes.