An empirical evaluation of two assessment methods for utility measurement for life years

Measurements of utility functions over life years provide useful information for decision making in the health care field. However, biases in the assessment procedures of utility functions is a well-known and documented phenomenon. In this paper we investigate possible biases in the assessment of utility functions when two different methods (direct and indirect assessment) are used. More specifically, we examine the estimation of utility functions over different lengths of life. The main findings, obtained from an empirical investigation in which the two assessment techniques were applied to a sample of students, are: (a) the use of the different methods does not lead to significant differences in the utility evaluation from a social point of view (health program evaluation); (b) the use of the different methods does lead to significant differences in the utility evaluation from an individual point of view (clinical decision making); (c) in both methods risk aversion was found to be common for shorter periods of time while risk prone behavior, when it exists, was found mainly for longer periods of time.