Integrating expert judgment in veterinary epidemiology: example guidance for disease freedom surveillance

Expert opinions supplement empirical data in many epidemiologic assessments. For veterinary disease freedom surveillance, where the geographic scope of concern is often broad, populations subject to change, decisions eminent and empirical data, expert opinion can be a critical component of the decision making process. However, opinion is by definition subjective and the manner in which opinion is sought can impact the quality and reliability of estimates. Group interaction can hinder or improve the estimation process, depending on its facilitation. Further, whether and how validation is conducted can limit or increase acceptance of the resulting model. While the utility of expert opinion is widely recognized in many fields, and the impact of its use or misuse implicit, standards for application to veterinary assessments are not readily available. This paper aims to foster discussion on this influential component of epidemiology, with disease freedom application as a focus. Benefits and concerns attributed to expert judgment and guidelines for its structured elicitation are described, borrowing insights from its long history of use in decision science fields and examples from recent veterinary assessments.