ABSTRACT
This chapter explores uncertainties in risk assessment and how they impact subsequent risk-management decisions. Risk assessment is an important tool for informing many kinds of societal decisions. Uncertainty is concerned with statistical confidence in data. For any particular predictive theory, the values of risk coefficients and other theory parameters are important sources of uncertainty. Risk information is not very useful in risk-management decision making without considering the magnitude and sources of uncertainties. Risk-reduction strategies that have little chance of improving public health and safety divert valuable resources from programs that may have significant health impacts. Dose and risk estimates have associated uncertainties that must be considered in comparing values with limits. Regulatory limits and administrative levels do not, by definition, have uncertainties. The large uncertainties typically encountered in environmental and occupational settings beg the question of the utility of risk information in decision making.
