The healthy-years equivalents: how to measure them using the standard gamble approach.

The healthy-years equivalent (HYE) is a measure of outcome of health care programs that combines two outcomes of interest: quality of life and quantity of life. Unlike QALYs (quality-adjusted life years) HYEs fully represent patients' (or other individuals') preferences, as a result of the way they are calculated from each individual's utility function. The authors suggest an algorithm to measure the HYE of any given lifetime health profile. The algorithm is based on the classic standard gamble method to measure individuals' preferences under uncertainty, and consists of two lottery questions. Algorithms for the general case (any given lifetime health profile) and a simpler case--the chronic health state case--are provided, as is a modification of the algorithm aimed at shortening the length of the interview when an individual is faced with many possible lifetime health profiles. In addition, two questions are addressed. The first is theoretical and deals with the existence of HYE: do all lifetime health profiles, which are preferred to death, have hypothetical equivalents that can be measured in healthy years? The second is empirical and deals with the reproducibility of the measures obtained by using the measurement technique suggested. This is needed because the technique employs a combination of lottery questions that had not previously been used together. The results of an experiment performed to test the reproducibility of the measures were satisfactory.