Keywords: consent probability, dependability, experts, judgemental probability, risk analysis, risk assessment, engineering decision making, due diligence
The quality of a risk analysis depends on the quality of its constituent probabilities, which are often subject to doubt. The passe (but still widely accepted) dichotomy between subjective and objective probabilities is shown to be inadequate for decision making. Invoking Karl Popper's three-world ontogeny, two other concepts of particular relevance to engineering decision making are introduced: judgemental probability and consent probability, which should satisfy the professional criterion of 'due diligence'. Criteria are suggested to help assess the quality of given probabilities.