Benchmark exercise on expert judgment techniques in PSA Level 2

This article summarizes objectives and aims of the concerted action 'Benchmark Exercise on Expert Judgment Techniques in PSA Level 2' and the results obtained within the project. The project was organized in three phases, namely a survey phase (pre-phase), a first phase devoted to parameter estimation assessment and a second phase devoted to benchmarking expert judgment methods on a scenario development case. The paper is focused on the first phase and on the results obtained by the application of five structured Expert Judgment (EJ) methodologies to the problem at hand. The results of the comparison of EJ methodologies are also provided; they are based on the use of some metrics suitably designed during the project. The context of Phase 2 and the issue to be tackled in this phase are briefly described; since this phase has been carried out only at a preliminary level (mainly after the end of the project), the results obtained are not reported here in detail but are only briefly commented on