Morbidity and Mortality: How Do We Value the Risk of Death and Illness? Session 4

We report several contingent valuation surveys to elicit willingness-to-pay for risk reductions associated with decreases in exposure to a chemical, PCBs, in the environment. We also develop Quality Adjusted Life Years (QALYs) from the survey using either standard gamble or time-tradeoff elicitation methods to explore the relationship between QALYs and willingness to pay (WTP), and to develop QALY weights for subtle developmental effects. The results of the contingent valuation are designed for incorporation into an integrated risk model to demonstrate the economic impact of risk reductions. Respondents showed a positive and proportional relationship between decreasing the risk of a 6-point reduction in IQ and WTP. Socioeconomic variables were not statistically significant predictors of WTP, while behavioral variables were strongly predictive and statistically significant. The range of mortality risks that respondents would accept on behalf of their (hypothetical) 10-year-old child is 2 in 10,000 to 9 in 1,000 per IQ point, and WTP per IQ point is $466 (95% confidence interval = $380, $520). QALY weights elicited via time tradeoff (reduction in life expectancy) were statistically significantly different from QALY weights elicited via a standard gamble. Respondents who answered questions about ecological endpoints first were willing to pay a small additional amount when asked about human health effects, but those respondents who answered questions about human health endpoints first were not willing to pay any additional amount when subsequently asked about ecological effects. WTP models demonstrate the importance of obtaining behavioral and cognitive information from respondents when eliciting WTP and in tests of sensitivity to scope.