A Discrete Choice Experiment to Obtain a Tariff for Valuing Informal Care Situations Measured with the CarerQol Instrument

Abstract

Economic evaluations adopting a societal perspective need to include informal care whenever relevant. However, in practice, informal care is often neglected, because there are few validated instruments to measure and value informal care for inclusion in economic evaluations. The CarerQol, which is such an instrument, measures the impact of informal care on 7 important burden dimensions (CarerQol-7D) and values this in terms of general quality of life (CarerQol-VAS). The objective of the study was to calculate utility scores based on relative utility weights for the CarerQol-7D. These tariffs will facilitate inclusion of informal care in economic evaluations. The CarerQol-7D tariff was derived with a discrete choice experiment conducted as an Internet survey among the general adult population in the Netherlands (N = 992). The choice set contained 2 unlabeled alternatives described in terms of the 7 CarerQol-7D dimensions (level range: "no,""some," and "a lot"). An efficient experimental design with priors obtained from a pilot study (N = 104) was used. Data were analyzed with a panel mixed multinomial parameter model including main and interaction effects of the attributes. The utility attached to informal care situations was significantly higher when this situation was more attractive in terms of fewer problems and more fulfillment or support. The interaction term between the CarerQol-7D dimensions physical health and mental health problems also significantly explained this utility. The tariff was constructed by adding up the relative utility weights per category of all CarerQol-7D dimensions and the interaction term. We obtained a tariff providing standard utility scores for caring situations described with the CarerQol-7D. This facilitates the inclusion of informal care in economic evaluations.