Psychometric evaluation and factor structure of the Hungarian CASP-19: methodological and practical implications from an ageing population

Quality of life in later life extends beyond physical health to include psychological and social domains. The CASP-19 is one of the most widely used instruments for assessing psychosocial quality of life in ageing populations; however, previous studies have reported inconsistencies in its factor structure across cultural contexts, particularly regarding the distinction between the control and autonomy dimensions. The present study evaluated the psychometric properties and structural characteristics of the Hungarian CASP-19 and the methodological implications of adapting its response format. A cross-sectional study was conducted among 223 Hungarian-speaking participants aged 50 years and above. The Hungarian adaptation of the CASP-19 was administered using a modified agreement-based response format. Psychometric evaluation included principal axis factoring with varimax rotation, with parallel analysis and oblique rotation as sensitivity analyses, followed by confirmatory factor analysis comparing six structural models estimated from polychoric correlations with WLSMV. Internal consistency was assessed using Cronbach’s alpha and McDonald’s omega, while convergent validity was examined using the EuroQol 5-Dimension 5-Level questionnaire (EQ-5D-5 L), the 36-Item Short Form Health Survey (SF-36), and the Mental Health Quality of Life questionnaire (MHQoL). CASP-19 total scores of respondents completing the paper-based and the online version were compared in a propensity score-matched subsample using matched-pair t-tests; no participant completed both formats. The Hungarian CASP-19 demonstrated high internal consistency (Cronbach’s α = 0.91). Principal axis factoring yielded a four-factor solution explaining 53.1% of the total variance, although sensitivity analyses supported fewer factors. All Autonomy items and most Control items loaded on a common factor, indicating limited empirical separation between these theoretical domains. The Autonomy subscale showed the weakest internal consistency (α = 0.69), consistent with the factor-analytic finding. The questionnaire showed moderate-to-strong correlations with other quality-of-life and well-being measures, supporting convergent validity. Total scores did not differ between the matched paper-based and online subgroups; as these comprised different individuals and only 26 pairs, this cannot be interpreted as evidence of measurement equivalence. The Hungarian CASP-19 showed high internal consistency and interpretable structural characteristics, supporting its use for assessing psychosocial quality of life in adults aged 50 and over. The findings did not support a strictly separated four-dimensional interpretation, particularly with regard to the Control and Autonomy domains, adding cross-cultural evidence to ongoing questions concerning the CASP framework. The study also highlights the methodological relevance of response format adaptation in later-life research. Not applicable.