A utility-theoretic approach to the aggregation of willingness to pay measured in decomposed scenarios: development and empirical test
For cost-benefit analysis, health technologies with multiple effects should be valued in a single scenario by a holistic willingness-to-pay (WTP) measure. Recent studies instead used decomposed scenarios in which respondents report their WTP for each individual effect. Evidence can be found that the sum of such decomposed WTPs overestimates the holistic WTP, i.e. the holistic WTP is sub-additive. This sum of decomposed WTPs can lead to wrong conclusions on the efficiency of health technologies. This is also relevant in decision making about new technologies that are valued separately in different surveys. To date, no utility-theoretical and empirically validated aggregation function for decomposed WTPs exists. Within an expected utility model, this paper identifies as a reason for sub-additivity - beside risk aversion with respect to wealth - a negative influence of better health on the marginal utility of wealth, i.e. marginal utility of wealth is smaller in better health states. Assuming mutual utility independence of health and wealth, a theoretically founded aggregation function covering these two impacts is derived. In a contingent valuation study, 92 patients with diabetes were asked to state their WTP for reductions of the risk of several diabetic complications in decomposed as well as in holistic scenarios. The patients had preferences with a significant negative influence of health on the marginal utility of wealth. Sub-additivity occurred and theoretically founded aggregation could considerably lower the degree of overestimation. These results suggest that the theoretically founded aggregation function might reduce problems of sub-additivity that can be economically relevant. Further empirical testing of the approach is indicated. Copyright © 2003 John Wiley & Sons, Ltd.
Volume (Year): 13 (2004)
Issue (Month): 4 ()
|Contact details of provider:|| Web page: http://www3.interscience.wiley.com/cgi-bin/jhome/5749|
References listed on IDEAS
Please report citation or reference errors to , or , if you are the registered author of the cited work, log in to your RePEc Author Service profile, click on "citations" and make appropriate adjustments.:
- Johansson,Per-Olov, 1995. "Evaluating Health Risks," Cambridge Books, Cambridge University Press, number 9780521478786.
- Sloan, Frank A. & Kip Viscusi, W. & Chesson, Harrell W. & Conover, Christopher J. & Whetten-Goldstein, Kathryn, 1998. "Alternative approaches to valuing intangible health losses: the evidence for multiple sclerosis1," Journal of Health Economics, Elsevier, vol. 17(4), pages 475-497, August.
- Kahneman, Daniel & Knetsch, Jack L., 1992. "Valuing public goods: The purchase of moral satisfaction," Journal of Environmental Economics and Management, Elsevier, vol. 22(1), pages 57-70, January.
- Randall, Alan & Hoehn, John P., 1996. "Embedding in Market Demand Systems," Journal of Environmental Economics and Management, Elsevier, vol. 30(3), pages 369-380, May.
- Viscusi, W Kip & Evans, William N, 1990. "Utility Functions That Depend on Health Status: Estimates and Economic Implications," American Economic Review, American Economic Association, vol. 80(3), pages 353-374, June.
- Eckerlund, Ingemar & Johannesson, Magnus & Johansson, Per-Olov & Tambour, Magnus & Zethraeus, Niklas, 1995. "Value for money? A contingent valuation study of the optimal size of the Swedish health care budget," Health Policy, Elsevier, vol. 34(2), pages 135-143, November.
- Phillips, Kathryn A. & Homan, Rick K. & Luft, Harold S. & Hiatt, Patricia H. & Olson, Kent R. & Kearney, Thomas E. & Heard, Stuart E., 1997. "Willingness to pay for poison control centers," Journal of Health Economics, Elsevier, vol. 16(3), pages 343-357, June.
- Stéphane Luchini & Christel Protière & Jean-Paul Moatti, 2003. "Eliciting several willingness to pay in a single contingent valuation survey: application to health care," Health Economics, John Wiley & Sons, Ltd., vol. 12(1), pages 51-64.
- Keeney,Ralph L. & Raiffa,Howard, 1993. "Decisions with Multiple Objectives," Cambridge Books, Cambridge University Press, number 9780521438834.
- Evans, William N & Viscusi, W Kip, 1991. "Estimation of State-Dependent Utility Functions Using Survey Data," The Review of Economics and Statistics, MIT Press, vol. 73(1), pages 94-104, February.
- Thomas Klose, 2003. "A utility-theoretic model for QALYs and willingness to pay," Health Economics, John Wiley & Sons, Ltd., vol. 12(1), pages 17-31.
- Johannesson, Magnus, 1996. "A note on the relationship between ex ante and expected willingness to pay for health care," Social Science & Medicine, Elsevier, vol. 42(3), pages 305-311, February.
- Peter A. Diamond & Jerry A. Hausman, 1994. "Contingent Valuation: Is Some Number Better than No Number?," Journal of Economic Perspectives, American Economic Association, vol. 8(4), pages 45-64, Fall.
- Klose, Thomas, 1999. "The contingent valuation method in health care," Health Policy, Elsevier, vol. 47(2), pages 97-123, May.
- John H. Beck, 1994. "An Experimental Test of Preferences for the Distribution of Income and Individual Risk Aversion," Eastern Economic Journal, Eastern Economic Association, vol. 20(2), pages 131-145, Spring.
- Blumenschein, Karen & Johannesson, Magnus & Yokoyama, Krista K. & Freeman, Patricia R., 2001. "Hypothetical versus real willingness to pay in the health care sector: results from a field experiment," Journal of Health Economics, Elsevier, vol. 20(3), pages 441-457, May.
- Dubourg, W R & Jones-Lee, M W & Loomes, Graham, 1994. "Imprecise Preferences and the WTP-WTA Disparity," Journal of Risk and Uncertainty, Springer, vol. 9(2), pages 115-133, October.
- Johansson,Per-Olov, 1995. "Evaluating Health Risks," Cambridge Books, Cambridge University Press, number 9780521472852.