Peer Review Report For: Exploring the structural characteristics of the Adult Social Care Outcomes Toolkit (ASCOT) and ASCOT-Carer [version 1; peer review: 2 approved with reservations

Abstract

Background: Measurement models inform the approach to assess a measure’s validity and also how a measure is understood, applied and interpreted. With preference-based measures, it is generally accepted that they are formative ; however, if they are applied without preferences, they may be reflective , formative or mixed . In this study, we sought to empirically test whether the reflective , formative or mixed measurement model best describes PBMs of social care-related quality of life (ASCOT, ASCOT-Carer). We also explored the network approach, as an alternative. Methods: ASCOT and ASCOT-Carer data were analyzed using confirmatory factor analysis and Multiple Indicators Multiple Causes models to test reflective, formative or mixed measurement models, respectively. Network analysis of partial correlations using the Gaussian graphical model was also conducted. Results: The results indicated that the reflective measurement model is the worst fit for ASCOT and ASCOT-Carer. The formative or mixed models may apply to ASCOT. The mixed model was the best fit for ASCOT-Carer. The network analysis indicated that the most important or influential items were Occupation and Personal cleanliness and comfort (ASCOT) and Time and space and Self-care (ASCOT-Carer). Conclusions: The ASCOT and ASCOT-Carer are best described as formative/mixed or mixed models, respectively. These findings may guide the approach to the validation of cross-culturally adapted and translated versions. Specifically, we recommend that EFA be applied to establish structural characteristics, especially if the measure will be applied as a PBM and as a measure of SCRQoL. Network analysis may also provide further useful insights into structural characteristics.