An overview of methods and applications to value informal care in economic evaluations of healthcare
This paper compares several applied valuation methods for including informal care in economic evaluations of healthcare programmes: the proxy good method; the opportunity cost method; the contingent valuation method (CVM); conjoint measurement (CM); and valuation of health effects in terms of health-related quality of life (HR-QOL) and well-being. The comparison focuses on three questions: what outcome measures are available for including informal care in economic evaluations of healthcare programmes; whether these measures are compatible with the common types of economic evaluation; and, when applying these measures, whether all relevant aspects of informal care are incorporated. All types of economic evaluation can incorporate a monetary value of informal care (using the opportunity cost method, the proxy good method, CVM and CM) on the cost side of an analysis, but only when the relevant aspects of time costs have been valued. On the effect side of a cost-effectiveness or cost-utility analysis, the health effects (for the patient and/or caregiver) measured in natural units or QALYs can be combined with cost estimates based on the opportunity cost method or the proxy good method. One should be careful when incorporating CVM and CM in cost-minimization, cost-effectiveness and cost-utility analyses, as the health effects of patients receiving informal care and the carers themselves may also have been valued separately. One should determine whether the caregiver valuation exercise allows combination with other valuation techniques. In cost-benefit analyses, CVM and CM appear to be the best tools for the valuation of informal care. When researchers decide to use the well-being method, we recommend applying it in a cost-benefit analysis framework. This method values overall QOL (happiness); hence it is broader than just HR-QOL, which complicates inclusion in traditional health economic evaluations that normally define outcomes more narrowly. Using broader, non-monetary valuation techniques, such as the CarerQol instrument, requires a broader evaluation framework than cost-effectiveness/cost-utility analysis, such as cost-consequence or multicriteria analysis.