We review the applications of structured expert judgment uncertainty quantification using the "classical model" developed at the Delft University of Technology over the last 17 years [Cooke RM. Experts in uncertainty. Oxford: Oxford University Press; 1991; Expert judgment study on atmospheric dispersion and deposition. Report Faculty of Technical Mathematics and Informatics No.01-81, Delft University of Technology; 1991]. These involve 45 expert panels, performed under contract with problem owners who reviewed and approved the results. With a few exceptions, all these applications involved the use of seed variables; that is, variables from the experts' area of expertise for which the true values are available post hoc. Seed variables are used to (1) measure expert performance, (2) enable performance-based weighted combination of experts' distributions, and (3) evaluate and hopefully validate the resulting combination or "decision maker". This article reviews the classical model for structured expert judgment and the performance measures, reviews applications, comparing performance-based decision makers with "equal weight" decision makers, and collects some lessons learned. (c) 2007 Elsevier Ltd. All rights reserved.
