Measurement of health state utilities for economic appraisal.

Health status measurement for use in economic appraisal of health care programmes is reviewed in this paper, with particular emphasis on utility measurement. A framework for economic appraisal is presented displaying the various components that must be measured, and showing how the three forms of analysis (cost-effectiveness analysis, cost-benefit analysis and cost-utility analysis) relate to the framework and to each other. One of the components in the framework is health status; it can be measured using ad hoc numeric scales, willingness to pay/receive or health state utilities. The determination of health state utilities is reviewed covering the following issues: alternative sources of utilities, health state descriptions, multi-attribute utility approach, determination of appropriate subjects, utility aggregation, and accuracy. Three measurement techniques for health state utilities are described in detail: rating scale, standard gamble, and time trade-off. The use of these methods is described for both chronic and temporary health states and for both health states considered better than death and those considered worse than death.