A court-appointed expert is obligated to provide a fact-based opinion. Whether they are retained by the parties in a case or by stipulation of the courts, they are subject to varying standards of admissibility based on legal decisions such as Daubert and its progeny. Consequently, the facts, scientific principles, and methodologies that underlie an expert opinion must result in valid and reasonably accurate conclusions. If an expert’s opinions are not credible or reliable, they may be excluded from the trier of fact.
When it comes to forming an expert opinion, the amount of work and resources invested by the expert will often determine its value and credibility in the eyes of a judge or other fact-finder. An expert should only accept cases that allow him to devote the necessary time and resources to a thorough analysis and formulation of an opinion that is defensible and compelling. An expert who insists on accepting such work will not be able to produce an accurate, comprehensive, or persuasive opinion, even if it is favorable for his client.
An expert is permitted to receive information that is not available to the general public on which to form an opinion, and he or she is expected to disclose these sources in a report if asked about them during cross-examination. However, experts must be careful not to rely too heavily on this type of information. Often, this information is the result of tabulations that have been done by lawyers who do not understand the methodology involved.