The CASP-19 as a measure of quality of life in old age: Evaluation of its use in a retirement community

Abstract

Purpose: The CASP-19 is a quality-of-life measure comprising four domains ('control', 'autonomy', 'pleasure' and 'self-realization'), developed initially in a population aged 65-75 years. This study tested the scale for use in a population whose demographic profile and residential status differed markedly from the original population. Methods: CASP-19 data were gathered from 120 residents of a UK retirement community. Distribution of scores, factor structure, internal consistency and construct validity were examined. Results: Scores were negatively skewed, especially on the pleasure domain. Attempts to confirm the factor structure of the scale were equivocal. Coefficients for composite reliability ranged from 0.52 to 0.84 across domains. Some items, particularly in the control and autonomy domains, showed low correlations with their domains. The CASP-19 correlated with the Diener Satisfaction with Life Scale (r = 0.66), and the physical (r = 0.53) and mental (r = 0.49) component summaries of the SF-12, supporting its construct validity. A recently proposed 12-item version of the scale appears to have superior dimensionality. Conclusion: Although in some respects the CASP-19 exhibited good psychometric properties, the internal consistency and dimensionality of the control and autonomy domains are suspect. Further modification of the scale may be fruitful from a psychometric point of view. © 2011 Springer Science+Business Media B.V.