Elicitation

The elicitation of imprecise probabilities is a relatively unexplored topic, and so some parts of this chapter draw from work on precise probability judgements. Most methods of eliciting imprecise probabilities fall into three groups: direct numerical estimates, numerical translations of verbal probability expressions, and evaluations of candidate intervals or bounds. The chapter first discusses the issues and methods in evaluating judged imprecise probabilities. It then examines methods for evaluating judged probabilities that can be adapted and applied to imprecise probability judgements. The chapter describes the factors that influence probability judgements and ways in which elicitation methods may be matched with the purposes intended to be served by elicitation. It reviews three influences on subjective interval estimates and probability judgements that have generated the greatest concerns about their validity: over- and under-weighting, overconfidence, and partition dependence. Finally, the chapter provides a guide to further reading on elicitation.