In many fields and industries, it is important to have expert opinions. They can be used to assess issues, determine risks and make recommendations on how to proceed or avoid certain pitfalls. While experts may use their education, training and practical experience to develop these opinions, they must carefully weigh and balance that information to ensure they are credible. When forming an opinion, they must also be careful not to cross over certain boundaries that can render them inadmissible in court.
One way to reduce the risk of an opinion being rendered inadmissible is for the expert to provide evidence of the source and reliability of their information. In addition, the expert should be able to testify as to the reasons for any inferences they make. This may include references to scientific literature and experimental data, as well as the expert’s own experience and knowledge.
It is also important for an expert to be able to defend their opinions on cross-examination. This may involve discussing the amount of time they spent on their work, whether they reviewed all pertinent materials and information, how they conducted any tests, the methods they used to perform those tests and analyzing and documenting those results. In addition, the expert should be questioned about any conflicts of interest or potential bias.
Using expert opinions to guide regulatory policy can be a cost-effective alternative to collecting primary field or survey data on any ecosystem service. However, the quality of such information cannot be guaranteed; large disagreements between experts imply poor information quality (Kangas et al., 1998). Furthermore, the expertise of an individual can vary based on a number of factors, including his or her personality, demeanor and ability to organize, express, and interpret complex concepts for a jury.