Health state values from multiattribute utility instruments need correction.

Cost-utility analysis uses the quality-adjusted life year (QALY) as a measure of the benefit of health interventions. It presupposes the assignment of utility scores to different states of health on a scale from zero (dead) to unity (healthy). A number of so-called multiattribute utility (MAU) instruments are available for this purpose. Analysts who wish to use MAU instruments in economic evaluations of health programmes and technologies may improve their performance by conducting two different analyses: the first is a conventional cost-utility study, in which the utilities from MAU instruments are used as they stand, and the second is a study in which the utilities are transformed into numbers that also encapsulate concerns for giving priority to the worst off. The term 'cost-value analysis' is used for the latter, broader approach. A figure is offered as a preliminary tool to help conduct the required transformations.