Psychometric Properties of the CASP-12 Scale in Portugal: An Analysis Using SHARE Data

• Main Authors: Carmen Rodríguez-Blázquez, Oscar Ribeiro, Alba Ayala, Laetitia Teixeira, Lia Araújo, Maria João Forjaz
• Format: Article
• Language: English
• Published: MDPI AG 2020-09-01
• Series: International Journal of Environmental Research and Public Health
• Subjects: quality of life; CASP-12; Rasch model; older adults; Portugal
• Online Access: https://www.mdpi.com/1660-4601/17/18/6610
• ISSN: 1661-7827; 1660-4601

The purpose of this study is to assess the psychometric properties of the Portuguese version of the Control, Autonomy, Self-realization, and Pleasure (CASP)-12 scale used in the Survey of Health, Aging and Retirement in Europe (SHARE) project. Data were obtained from a representative sample of 1666 people aged ≥50 years living in Portugal and participating in the SHARE wave 6. In addition to the CASP-12 scale, sociodemographic data and health status, activity limitation (GALI), depression (Euro-D) and satisfaction with life scores were collected. Data quality and acceptability, construct and structural validity and internal consistency of the CASP-12 scale were analyzed. A Rasch analysis was also performed. CASP-12 total score (mean: 33.3; standard deviation: 5.8, range: 12–48) correlated with Euro-D (−0.57) and with life satisfaction (0.52). Mean scores were significantly lower for women, people aged ≥75 years and those with activity limitations and worse health status (<i>p</i> < 0.001). The confirmatory factor analysis showed good fit to the 4-factor model (root mean squared error of approximation (RMSEA): 0.07; comparative fit index (CFI): 0.90, χ² (48) = 444.59, <i>p</i> < 0.001), which was confirmed by Rasch analysis (χ² (36) = 10.089, <i>p</i> = 0.745, person separation index (PSI) = 0.722 for the 4-factor model). For domains, person separation index ranged 0.31–0.79 and Cronbach’s alpha, 0.37–0.73. In conclusion, the Portuguese version of the CASP-12 scale presents some inadequacies in acceptability, internal consistency and structural validity.