Elicitation and Calibration: A Bayesian Perspective

There are relatively few published perspectives on processes and procedures for organising the elicitation, aggregation and documentation of expert judgement studies. The few that exist emphasise different aggregation models, but none build a full Bayesian model to combine the judgements of multiple experts into the posterior distribution for a decision maker. Historically, Bayesian concepts have identified issues with current modelling approaches to aggregation, but have led to models that are difficult to implement. Recently Bayesian models have started to become more tractable, so it is timely to reflect on elicitation processes that enable the model to be applied. That is our purpose in this Chapter. In particular, the European Food Safety Authority have provided the most detailed and thorough prescription of the procedures and processes needed to conduct an expert judgement study. We critically review this from a Bayesian perspective, asking how it might need modifying if Bayesian models are included to analyse and aggregate the expert judgements.