Comparing the German translation of the ICECAP-A capability wellbeing measure to the original English version: psychometric properties across healthy samples and seven health condition groups

As the cross-cultural use of outcome measures grows, it is important to determine whether these instruments are: appropriate for use in other settings, translated accurately, and perform in a similar manner to their original tools. This research aimed to compare the validity of the German translation of the ICECAP-A to the original English version of the instrument, across healthy adults and seven health condition groups (arthritis, asthma, cancer, depression, diabetes, hearing loss and heart disease). Data were analysed from a cross-cultural study, which recruited participants through online panels in 2012. Data were analysed on capability wellbeing (ICECAP-A), health-related quality of life (EQ-5D-5L and SF-6D), satisfaction with life (SWLS), and a series of other condition-specific outcome measures. The ICECAP-A was assessed for internal consistency, convergent validity and construct validity. 2501 individuals were included in the analysis. The ICECAP-A demonstrated good internal consistency within Germany and the UK population, and across all seven health condition sub-groups (α =.74–.86). In both countries, ICECAP-A scores were significantly correlated with SWLS, SF-6D and EQ-5D-5L scores for healthy participants and health condition groups (r =.35–.77). Finally, experiencing one of the seven health conditions (compared to being healthy) was significantly associated with lower levels of capability wellbeing in the German and UK samples (construct validity). The German translation of the ICECAP-A yielded valid and reliable data, in both healthy respondents and the seven health condition groups. Further work could be undertaken to develop a German specific value-set for the ICECAP-A.