Current studies have shown that older people´s Quality of Life (QoL) is more associated to individual´s sense of happiness and subjective life satisfaction than to objective problems, such as physical functioning. In this regard, CASP scale conceptualizes QoL based in a psycho-sociological perspective.
Originally it consisted of 19 items grouped by four factors: control, autonomy, self-realization and pleasure. Later, Wiggins, Netuvelli, Hyde, Higgs and Blane (2008) proposed a shorter version including 12 items and three factors (control combined with autonomy, pleasure and self-realization). Regarding these discrepancies in the CASP factor structure, there was a lack of studies comparing which model works better for Spanish population.
Although life expectancy has increased in the past decades, it is also surprising that several studies using CASP scale to assess older people´s QoL have included people younger than 60 years old, such as the SHARE project, in which people aged 50 years old and over participated. The consideration of people aged 60 and over is especially important in order to assess adequately older people´s needs and resources.
Regarding the lack of studies that have validated the CASP-12 in older people exclusively, we assessed the structure of the CASP-12 SHARE version using confirmatory factor analysis (CFA) in a sample of 1,108 people aged 60 years and over from Spain. Thus, considering the contradictory hypotheses stated to date, we checked the CASP structures traditionally proposed (one-dimensional, four dimension first-order factor and second order factor model) and tested, for the first time, the three domains model proposed by Wiggins et al. (2008) with the objective of constructing a model with acceptable fit to the data that also retains the theoretical value of the scale.
We found that the three factor model showed a good overall fit: 1) pleasure, 2) self-realization and 3) autonomy and control. In contrast, the other tested models showed a lower overall fit. The three-factor model seemed to be more appropriate, suggesting the need to unite the factors control and autonomy in one domain. Since life satisfaction arises from feelings of mastery which includes aspects of control and autonomy, it is not surprising that control and autonomy belonged to the same factor. Also, an adequate internal consistency was obtained.
The study results suggest that the Spanish CASP-12 presents a factorial structure and reliability indexes similar to its original version. Thus, our study provides empirical evidence of the importance of the assessment of QoL in older people using a broader and a holistic approach that is different from the approach based on the dominant paradigm of decline in older people. Knowing that QoL acts as a significant mediator between chronic and disabling conditions and the perceived effects of burden, having QoL assessment instruments with strong psychometric support may contribute to give a better answer to older people needs.
To sum up, this is one of the first, and the largest study on the levels and psychometric properties of CASP-12 in Spain. CASP-12 is a valid and reliable tool for assessing QoL among older adults aged 60 years or older. Quality of life in later life has become a major global policy and research issue. This version of CASP is recommended to be used in future studies investigating QoL in Spanish population. This study provides Spanish-speaking countries a good scale to measure QoL in later life. Hopefully, future studies in these countries will be able to use this scale when assessing the impact of Public Health services and cross-cultural comparisons.
Posted by Gema Pérez-Rojo1, Noemy Martín2, Cristina Noriega1 and Javier López1
1 CEU San Pablo University (Madrid, Spain)
2 Francisco de Vitoria University (Madrid, Spain)
Pérez-Rojo, G., Martín, N., Noriega, C., & López, J. (2017). Psychometric properties of the CASP-12 in a Spanish older community dwelling sample. Aging & Mental Health. doi:10.1080/13607863.2017.1292208