Head-to-Head Comparison of the Psychometric Properties of 3 Carer-Related Preference-Based Instruments [Editor's Choice]



To compare the psychometric properties of the Adult Social Care Outcomes Toolkit for carers (ASCOT-Carer), the Carer Experience Scale (CES), and the Care-related Quality of Life (CarerQol) to inform the choice of instrument in future studies.


Data were derived from a 2018 online survey of informal carers in Australia. Reliability was assessed via internal consistency (Cronbach alpha, α) and test-retest reliability (intraclass correlation coefficient, ICC) for respondents who self-reported no change in their quality of life as a carer over 2 weeks. Convergent validity was evaluated via predetermined hypotheses about associations (Spearman’s rank correlation) with existing, validated measures. Discriminative validity was assessed based on the ability of the carer-related scores to distinguish between different informal care situations (Mann–Whitney U, Kruskal–Wallis one-way analysis of variance).


Data from 500 carers were analyzed. The ASCOT-Carer demonstrated a higher degree of internal consistency, possibly due to a unidimensional structure, and test-retest reliability than the CarerQol and CES (α = 0.87, 0.65, 0.59; ICC, 0.87, 0.67, 0.81, respectively). All 3 instruments exhibited convergent validity and detected statistically significant associations between carer-related scores and different informal care situations, except for the CarerQol-7D and sole carer status.


The ASCOT-Carer, CarerQol, and CES performed reasonably well psychometrically; the ASCOT-Carer exhibited the best psychometric properties overall in this sample of Australian informal carers. Findings should be used in conjunction with consideration of research goals, carer population, targeted carer-related constructs, and prevailing perspectives on the economic evaluation to inform choice of instrument in future studies.


Nikki McCaffrey Jessica Bucholc Stacey Rand Renske Hoefman Anna Ugalde Anne Muldowney Cathrine Mihalopoulos Lidia Engel

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