Translation, cultural adaptation and construct validity of the German version of the Adult Social Care Outcomes Toolkit for informal Carers (German ASCOT-Carer)

PURPOSE: The Adult Social Care Outcomes Toolkit for Carers (ASCOT-Carer), developed in England, measures the effects of long-term care (LTC) services and carer support on informal carers’ quality of life (QoL). Translations of the ASCOT-Carer into other languages are useful for national and cross-national studies. The aim of this paper was to report on the translation and cultural adaptation of the original English ASCOT-Carer into German, to assess its content validity and to test for its construct validity (convergent and discriminative/known-group validity). METHODS: Translation and cultural adaptation followed the ISPOR TCA guidelines. As part of the translation and adaptation process, five cognitive debriefing interviews with informal carers were used for evaluating linguistic and content validity. In addition, a sample of 344 informal carers of older adults, who received home care services in Austria, was used for hypothesis testing as suggested by the COSMIN checklist to assess convergent and discriminative/known-group validity as part of construct validity. RESULTS: Cognitive interviews provided evidence that questions and response options of the German ASCOT-Carer were understood as intended. Associations between ASCOT-Carer scores/domains and related outcome measures (convergent validity) and expected groups of informal carers and the care service users they care for (discriminative validity) supported construct validity of the translated instrument. CONCLUSION: The German ASCOT-Carer instrument meets the required standards for content and construct validity which supports its usefulness for (cross-)national studies on LTC-service-related QoL-outcomes in informal carers. Research is encouraged to assess further measurement properties of the translated instrument. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s11136-020-02682-4) contains supplementary material, which is available to authorized users.