Uncertainties in Expert-Opinion Elicitation for Risk Studies

Risk assessment involves many uncertain quantities, only some fraction of which are amenable to statistics and modeling. Even when uncertainties are difficult to model, however, experts may have well-founded opinions about them. The use of judgmental probability allows for the inclusion of these types of uncertainties in risk assessment. The quantification of expert opinion in the form of judgmental probabilities and consequences of failure has become known as "expert-opinion elicitation." The rigor of such expert-opinion elicitation in practice varies from casual to careful, as does the veracity of resulting numbers. Uncertainties associated with the process of expert-opinion elicitation and its results will be described and discussed. A process of elicitation that is appropriate for risk studies will be outlined and its components described. The paper discusses example techniques for eliciting judgmental probabilities and consequences for dam safety studies for the purposes of simulation-based design and verification and validation (V&V) necessity for computational methods.