Expert judgment in assurance cases

摘要

Quantitative methods are usually preferred in safety assessment, but, frequently, necessary probabilities cannot be determined accurately. As a result, expert judgment plays a significant role in safety arguments and system deployment decisions. Trust in expert judgment is based on the assumption that the expert's experience, knowledge, and training will enable the expert to make a suitable decision. The record indicates, however, that this assumption does not always hold and that decisions tend to be ad hoc and unprincipled. In this paper we present an analysis of expert judgment and a rigorous process for utilizing expert judgment in safety arguments.