Guidance on Expert Knowledge Elicitation in Food and Feed Safety Risk Assessment
Quantitative risk assessments facilitate the decisions of risk managers. In the EU, risk assessment in food and feed safety is the responsibility of the European Food Safety Authority (EFSA). Quantitative risk models should be informed by systematically reviewed scientific evidence, however, in practice empirical evidence is often limited: in such cases it is necessary to turn to expert judgement. Psychological research has shown that unaided expert judgement of the quantities required for risk modelling - and particularly the uncertainty associated with such judgements - is often biased, thus limiting its value. Accordingly methods have been developed for eliciting knowledge from experts in as unbiased a manner as possible. In 2012, a working group was established to develop guidance on expert knowledge elicitation appropriate to EFSA's remit. The resulting Guidance first presents expert knowledge elicitation as a process beginning with defining the risk assessment problem, moving through preparation for elicitation (e.g. selecting the experts and the method to be used) and the elicitation itself, culminating in documentation. Those responsible for managing each of these phases are identified. Next three detailed protocols for expert knowledge elicitation are given - that can be applied to real-life questions in food and feed safety - and the pros and cons of each of these protocols are examined. This is followed by principles for overcoming the major challenges to expert knowledge elicitation: framing the question; selecting the experts; eliciting uncertainty; aggregating the results of multiple experts; and documenting the process. The results of a web search on existing guidance documents on expert elicitation are then reported, along with case studies illustrating some of the protocols of the Guidance. Finally, recommendations are made in the areas of training, organisational changes, expert identification and management, and further developments of expert knowledge elicitation methodology within EFSA.