A Systematic Review of the Feasibility and Psychometric Properties of the ICEpop CAPability Measure for Adults and Its Use So Far in Economic Evaluation

Objectives: Development of the ICEpop CAPability measure for Adults (ICECAP-A) was reported in 2012; use of certain capability measures was suggested in the context of social or long-term care soon afterward by decision-making organizations in the United Kingdom and The Netherlands. Despite enthusiasm for the ICECAP-A, this study represents the first attempt to collate evidence on its psychometric properties and its use in economic analysis. Methods: A systematic review of studies published between January 2012 and February 2019 that have either explored the psychometric properties of the ICECAP-A (validity, reliability, and responsiveness) or report its use in economic analysis. Results: Twenty-seven studies were identified, 11 undertaking some form of economic analysis (including pilot and feasibility studies) and 16 assessing psychometric properties (7 assessing construct validity). The ICECAP-A has mainly been used in the United Kingdom, but also in other English-speaking countries and in Europe, across a wide range of healthcare contexts. There is promising evidence on content validity, construct validity, and responsiveness. Although there was consistently strong associations between the ICECAP-A and the Assessment of Quality of Life-Eight Dimension, associations with the EuroQol 5-dimension 3-level and EuroQol 5-dimension 5-level were inconsistent. In some cases, it was found that a switch in evaluative space from health to capability well-being would alter resource allocation decisions. Conclusion: The ICECAP-A is correlated with health-related quality of life but is most appropriately regarded as a complement for and not a substitute to the EuroQol 5-dimension 3-level and EuroQol 5-dimension 5-level in particular. Positive evidence of the measures content and construct validity is beginning to accumulate, but further conceptual and policy debate is needed regarding the equity implications of switching between evaluative spaces.