Using life expectancy to communicate benefits of health care programs in contingent valuation studies

Abstract

Background: There is growing interest in the use of contingent valuation (CV) to estimate the monetary value of health program benefits. Ideally, CV could be used to value a specific shift in survival curve. However, a shift in survival curve may prove too complex for widespread use in CV instruments. To facilitate the use of CV in valuing longevity benefits, researchers need alternative summary measures that describe the longevity benefit in a single number that is more readily communicated in a CV context.

Methods: The authors compare 2 methods for communicating longevity benefits in a CV survey. Random subsamples of respondents valued a longevity benefit expressed either as a continuing reduction in annual mortality risk or as a gain in life expectancy. To compare the validity of the alternative descriptions, the authors evaluate willingness to pay (WTP) estimates for consistency with theoretical predictions.

Results: It is found that WTP for a longevity benefit is sensitive to the framing of the benefit, with respondents expressing higher WTP for the benefit expressed as a life expectancy gain. The life expectancy format performs better than the risk reduction format in one important regard-sensitivity to scope of the benefit-and no worse than the risk reduction format in other regards.

Conclusion: Expressing longevity benefits in terms of life expectancy appears to hold promise as a method for enhancing the validity of economic evaluation of health care programs.