Expert elicitation is a formal process in which quantitative information is gathered from an expert or a group of experts. Typically this information involves probabilities, consequences, costs, value structures, and other technical details. Expert elicitation is valuable when there is uncertainty due to insufficient data, or when such data are unattainable because of physical constraints or lack of resources. Information from expert elicitation is often used in decision analysis and Bayesian statistical analysis. Neptune and Company, Inc., has conducted a variety of elicitations for government and private clients. Examples include the following:

• For the Montana National Guard, we developed a model of risk from unexploded ordnance (UXO) at the North Helena Valley Site. Modeling involved using data, meta-data, and elicitation to build a model for spatial distribution of UXO, potential for exposure, and detonation. The Bayesian model also included a ballistic model for predicting firing patterns. Approximate cost savings to the National Guard have been estimated to be on the order of $10M.

• We modeled a site for volcanic activity and the likelihood of a disruptive volcanic event. Relatively little data were available, requiring the use of Bayesian models to integrate expert assessment with the data to produce a hazard estimate and the uncertainty associated with the estimate. The elicitation covered spatial aspects of the model, such as underlying stress fields, surface extension, lithostatic pressure, impact of volcanic dikes on faults, and the location of previous events, and temporal aspects, such as the timing of previous events. The goal was to estimate the probability of volcanic hazard to a radioactive waste repository.