Exploring the structural characteristics of the Adult Social Care Outcomes Toolkit (ASCOT) and ASCOT-Carer

Exploratory factor analysis and Rasch analysis to assess the structural validity of the Adult Social Care Outcomes Toolkit Proxy version (ASCOT-Proxy) completed by care home staff

PURPOSE

Rasch analysis and exploratory factor analysis (EFA) were used to evaluate the structural validity of the ASCOT-Proxy measures completed by staff on behalf of older adults resident in care homes, by comparison to the ASCOT-SCT4, the measure of social care-related quality of life (SCRQoL) from which the ASCOT-Proxy was developed.

METHODS

EFA was conducted on the ASCOT-SCT4 and the two ASCOT-Proxy measures (Proxy-Proxy, Proxy-Resident), to determine if they retained the single factor of the original ASCOT-SCT4 measure found in samples of older community-dwelling adults. Rasch analysis was also applied to measures with a single factor structure in the EFA.

RESULTS

ASCOT-Proxy-Resident had a single factor structure, as did the original ASCOT-SCT4 (also, found in this analysis when completed by care home staff). The ASCOT-Proxy-Proxy had a two factor structure. Rasch analysis of ASCOT-Proxy-Resident and ASCOT-SCT4 had an acceptable model fit, internal consistency and met the assumptions of unidimensionality and local independence. There was evidence of less than optimal distinguishability at some thresholds between responses, and low frequency of rating of the 'high level needs'.

CONCLUSION

The ASCOT-Proxy-Resident is a valid instrument of SCRQoL for older adults resident in care homes, completed by staff proxies. Due to the two-factor structure, which differs from the original ASCOT-SCT4, we do not recommend the use of the ASCOT-Proxy-Proxy measure, although collecting data as part of the ASCOT-Proxy questionnaire may support its feasibility and acceptability. Further qualitative study of how care home staff complete and perceive the ASCOT-Proxy is encouraged for future studies.

Feasibility, validity and reliability of the ASCOT-Proxy and ASCOT-Carer among unpaid carers of people living with dementia in England

BACKGROUND

People with dementia living at home represent a growing group of social care services users in England. Many are unable to complete questionnaires due to cognitive impairment. The ASCOT-Proxy is an adapted version of an established measure, ASCOT, which was developed as a way of collecting social care-related quality of life (SCRQoL) data from this group of service users, either alone or alongside the ASCOT-Carer, a measure of SCRQoL for unpaid carers. The ASCOT-Proxy includes two perspectives, the proxy-proxy perspective ('My opinion: What I think') and proxy-person perspective ('What I think the person I represent thinks'). We aimed to establish the feasibility, construct validity and reliability of the ASCOT-Proxy and ASCOT-Carer, with unpaid carers of people with dementia living at home unable to self-report. We also aimed to establish structural characteristics of the ASCOT-Proxy.

METHODS

Cross-sectional data were collected using self-administered questionnaire (paper or online) among unpaid carers living in England between January 2020 and April 2021. Unpaid carers could take part if they supported someone living with dementia who was unable to self-complete a structured questionnaire. The person living with dementia or their unpaid carer had to use at least one social care service. We used the proportion of missing data to establish feasibility, ordinal exploratory factor analysis to establish structural characteristics, Zumbo's ordinal alpha for internal reliability, and hypothesis testing for construct validity. We also conducted Rasch analysis.

RESULTS

We analysed data for 313 carers (62.4(± 12.0) years, 75.7% (N=237) females). We were able to calculate the ASCOT-Proxy-proxy overall score for 90.7% of our sample, the ASCOT-Proxy-person overall score for 88.8% of our sample and in case of the ASCOT-Carer for 99.7% of our sample. As there was an issue with structural characteristics of the ASCOT-Proxy-proxy we conducted Rasch, reliability and construct validity analysis for the ASCOT-Proxy-person and ASCOT-Carer only.

CONCLUSIONS

This was a first study to explore psychometric characteristics of the ASCOT-Proxy and ASCOT-Carer with unpaid carers of people with dementia living at home unable to self-report. There are some aspects of the psychometric characteristics of the ASCOT-Proxy and ASCOT-Carer that warrant further investigation in future. Trial registration NA.