Title: Bi-factor model of the control, autonomy, self-realization and pleasure scale (CASP-12) for general factor determination of quality of life in older adults
Authors : Kerry-Krause, Matthew J.
Conference details: International Measurement and Psychometrics Society, Santiago de Chile, 15.Juli - 17.Juli 2019
Issue Date: 2019
License (according to publishing contract) : Not specified
Type of review: Peer review (Abstract)
Language : English
Subjects : Item response theory; Patient-reported outcome; Quality of life; Bifactor model
Subject (DDC) : 362: Health and social services
Abstract: Patients' subscores on quality of life (QoL) measures can provide diagnostic information about strengths and weaknesses of respondents' performance in specific areas. Such diagnostics may help with identification of potential at-risk individuals. Subscores may also help with modifying extant care-treatment programs. The Control, Autonomy, Self-realization, and Pleasure (CASP) measure is one, popular QoL measure example with such subscore potential, which will be of focal interest and presented via the current poster submission. As the CASP’s author reassures researchers that “those who simply require a single index” may sum the CASP-12, it is important to first-determine if unidimensional usage in prediction models is reasonably unbiased by ignoring subdomains. As the CASP constructor’s concluded, “…strength of the inter-domain correlations….confirm our belief that QoL is a unitary phenomenon which is the product of the interactions between the domains”. In this first-IRT inspection of CASP’s psychometric properties, the CASP-12’s general QoL factor was found to be well-specified by a bifactor model for specifying subdomains/content homogeneity as sources of nuisance variance. Furthermore, the CASP-12’s total score (general factor) exhibited acceptably high reliability in older populations across both broader community-dwellers, as well as among narrower-patient respondents. In contrast, the CASP-12’s specific subfactors were found to exhibit unacceptably low reliability, suggesting only CASP-12’s global score is currently appropriate for substantive interpretation and meaningful use. Finally, the CASP’s original 12-item measure was identified as-having a potentially useful, 5-item subset for succinct indexing of QoL-unitary scores for future researchers’ use in structural-estimation models.
Departement: Health Professions
Organisational Unit: Institute of Health Sciences (IGW)
Publication type: Conference Poster
URI: https://digitalcollection.zhaw.ch/handle/11475/17327
Appears in Collections:Publikationen Gesundheit

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