Eliciting stated health preferences: an application to willingness to pay for longevity.

The economic analysis of many health policies requires evaluation of the benefits of programs that may prolong human lives. This article contributes to the development of credible values for longevity, demonstrating the feasibility of applying stated-preference market-research techniques to a new area of preference revelation and framing the problem as extending longevity under realistic health states associated with advanced age. Respondents to the authors' stated-preference survey clearly indicated that quality of life affects the value of quantity of life. The results demonstrate the sensitivity of life-extension values to specific health and activity-limitation conditions. The article also discusses problems that remain to be solved before valid and reliable longevity values can be obtained.