Expert frailties in conservation risk assessment and listing decisions

Listing decisions are a form of risk assessment supported largely by expert judgement. Expert judgements of rare events in novel circumstances are error prone. Experts are susceptible to social influences and their views are shaped by context, framing, and personal values. Expert judgment is a legitimate source of knowledge, but only if it is fallible.A range of behavioural and numerical methods may be employed to elicit, combine and communicate opinions in deliberation processes by expert groups. Expert groups provide an efficient and convenient way of synthesising a broad range of knowledge but their advice may be improved by training, feedback of performance, consistent communication formats, and awareness of motivational and other sources of bias. A suite of behavioural and numerical methods to aggregate opinions and communicate uncertainty provides new opportunities.