Psychometric Properties and Measurement Invariance of the Parental Health Locus of Control Scale in an Italian Population

Introduction. Parents play a pivotal role in shaping children’s health behaviors, preventive practices, and adherence to medical recommendations. The Parental Health Locus of Control (PHLOC) scale measures parental beliefs about the sources of control over child health outcomes. Although an Italian version exists, its psychometric properties had not yet been comprehensively evaluated. This study aimed to validate the Italian version of the PHLOC by assessing its factorial structure, internal consistency reliability, convergent validity with health literacy and vaccine hesitancy measures, and measurement invariance across healthcare professionals and non-healthcare professionals. Methods. A cross-sectional psychometric study was conducted among 308 Italian parents of children aged 0–18 years using EUSurvey®. Confirmatory factor analysis (CFA) tested the six-factor structure of the PHLOC (Parent, Child, Professionals, Media, Divine, Fate), and internal consistency was assessed with McDonald’s omega. Convergent validity was examined through correlations with health literacy (HLS-EU-Q6) and vaccine hesitancy (PACV-5). Measurement invariance by professional status was evaluated using a Multiple Indicators Multiple Causes (MIMIC) model. Results. CFA supported the six-factor model with good fit indices (CFI=0.954; TLI=0.949; RMSEA=0.068; SRMR=0.070). Internal consistency was satisfactory across subscales (ω=0.67-0.95). Correlations were consistent with theoretical expectations: higher health literacy and lower vaccine hesitancy were associated with lower endorsement of external attributions (Divine, Fate). The hierarchical second-order model (Internal, External-Powerful Others, External-Chance) yielded inadmissible solutions. Discussion. The Italian PHLOC demonstrated sound psychometric properties, supporting its validity, reliability, and measurement invariance. Future studies should further investigate higher-order structures and temporal stability to strengthen the scale’s theoretical and practical applications in research and clinical contexts.