The importance of perspective in the measurement of quality-adjusted life years.

Scaling instruments for the measurement of quality-adjusted life years (QALYs) incorporate either a personal or an impersonal perspective on the benefits of a health intervention and either do or do not incorporate considerations of equity. This paper sets out three hypotheses concerning perspective and equity: 1) that more equally distributed benefits will be preferred to less equally distributed benefits; 2) that the preference value elicited for a health benefit will be greater when the respondent to a QALY questionnaire is a potential beneficiary; and 3) that, by comparison with personal preferences, individuals will be more concerned with the quantity than the quality of life in other people. These hypotheses were tested using two existing instruments and two other instruments that were created for this study. Results gave no support to the third hypothesis; some support to the first hypothesis, and strong support for the second hypothesis. It is concluded that perspective can significantly alter the values incorporated in a QALY instrument. The policy implications of the results are twofold. First, they give some support to the view that distributional consequences of health programs are of importance to the population and that they should be included in the evaluation of any health program. Second, they indicate that an evaluation should consider whether the health-state values to be obtained should incorporate an impersonal perspective reflecting the purely "social" judgment of a health planner or a perspective reflecting self-interest.