ABSTRACT
Expert knowledge is technical information provided by qualified people responding to formal elicitation questions that address complex, often under-characterized technical problems or phenomena [1]. Expressions of expert knowledge are of interest to scholars in a wide range of fields: economics, medicine and epidemiology, computational sciences, risk and reliability assessments, engineering, statistics, and others. In its formal expression, expert knowledge is most frequently associated with expert judgment, often a significant data source for mathematical and scientific models that attempt to predict or characterize complex, highly uncertain, and rare phenomena-for example, the probability of a nuclear reactor core melt accident. Informally expressed, however, expert knowledge is always a major factor in scientific
research. This form of expert knowledge, which in this chapter is referred to as expertise, is articulated in the decisions that scientists and engineers make in selecting phenomena for study, identifying appropriate data sources, designing experiments, and choosing computational models. In short, expert knowledge is never absent from any research process, regardless of how formally it is elicited or expressed.
