AAAS Science & Technology Policy Fellow, U.S. Environmental Protection Agency, 1200 Pennsylvania Ave., NW, Washington, DC 20460, USA.
Diminishing Willingness to Pay per Quality-Adjusted Life Year: Valuing Acute Foodborne Illness
Article first published online: 13 APR 2011
© 2011 Society for Risk Analysis
Volume 31, Issue 9, pages 1363–1380, September 2011
How to Cite
Haninger, K. and Hammitt, J. K. (2011), Diminishing Willingness to Pay per Quality-Adjusted Life Year: Valuing Acute Foodborne Illness. Risk Analysis, 31: 1363–1380. doi: 10.1111/j.1539-6924.2011.01617.x
- Issue published online: 29 SEP 2011
- Article first published online: 13 APR 2011
- Foodborne illness;
- health risk;
- quality-adjusted life year;
- stated preference;
- willingness to pay
We design and conduct a stated-preference survey to estimate willingness to pay (WTP) to reduce foodborne risk of acute illness and to test whether WTP is proportional to the corresponding gain in expected quality-adjusted life years (QALYs). If QALYs measure utility for health, then economic theory requires WTP to be nearly proportional to changes in both health quality and duration of illness and WTP could be estimated by multiplying the expected change in QALYs by an appropriate monetary value. WTP is elicited using double-bounded, dichotomous-choice questions in which respondents (randomly selected from the U.S. general adult population, n = 2,858) decide whether to purchase a more expensive food to reduce the risk of foodborne illness. Health risks vary by baseline probability of illness, reduction in probability, duration and severity of illness, and conditional probability of mortality. The expected gain in QALYs is calculated using respondent-assessed decrements in health-related quality of life if ill combined with the duration of illness and reduction in probability specified in the survey. We find sharply diminishing marginal WTP for severity and duration of illness prevented. Our results suggest that individuals do not have a constant rate of WTP per QALY, which implies that WTP cannot be accurately estimated by multiplying the change in QALYs by an appropriate monetary value.