Time, age, gender and cultural measurement invariance of the CASP-12, a measure of psychological quality of life in adulthood.

Abstract

Whereas Quality of Life in older populations has long been conceptualized in regards to health or illness, the Control, Autonomy, Self-Realization and Pleasure scale (CASP-12) focuses on the positive facets of aging. Although the CASP is a widely used scale, its measurement invariance has seldom been examined. The present study aims to ascertain the measurement invariance of the CASP-12 over a period of 10years and between age, culture and gender. Secondary data analyses were conducted on the longitudinal data collected in four waves between 2006 and 2016-2017 of the Survey of Health, Ageing and Retirement in Europe study (SHARE). The factorial validity of the CASP-12 was examined and its measurement invariance was tested with a sample of 3684 men and 4955 women aged 30-99years, coming from 10 different European countries. Results showed a strong theoretical and empirical dimensionality of the CASP-12, a well as invariance of time (10years), age and culture. It was also found that the scale is gender invariant at the strict level. These results were replicated with two more waves of SHARE, measured six years apart. This study replicates the CASP-12 dimensional structure, factorial structure and factor loadings. The scale has demonstrated to be a reliable and valid measurement of the positive aspects of quality of life to be used across time, age, gender and culture. The Autonomy dimension of the scale warrants further investigation.