ALEATORY AND EPISTEMIC UNCERTAINTY IN PROBABILITY ELICITATION WITH ANEXAMPLE FROM HAZARDOUS-WASTE MANAGEMENT

The quantification of a risk assessment model often requires the elici tation of expert judgments about quantities that cannot be precisely m easured. The aims of the model being quantified provide important guid ance as to the types of questions that should be asked of the experts. The uncertainties underlying a quantity may be classified as aleatory or epistemic according to the goals of the risk process. This paper d iscusses the nature of such a classification and how it affects the pr obability elicitation process and implementation of the resulting judg ments. Examples from various areas of risk assessment are used to show the practical implications of how uncertainties are treated. An exten ded example from hazardous waste disposal is given. (C) 1996 Elsevier Science Limited.