Requisite Diversity of Expert Witness Testimony and Issues of Objectivity, Bias and Advocacy

Abstract

The United States’ court systems allow each litigant to retain qualified expert witnesses to provide opinion testimony under oath, in support of the litigant who retained the expert. The Court qualifies and admits the witness, and the expert testimony presented by each side is subject to cross examination. According to some legal systems in other countries, and also in some circumstances in the US, the Court itself may retain a single expert to provide technical evidence independent from any litigant’s perspective. However, because of an individual’s biases and because of inherent threats to objectivity, a single expert may not possess or be able to bring to bear the diversity of knowledge, experience, opinion or judgment to adequately evaluate all reasonable sides of a dispute. The subject of this paper is objectivity and bias of experts, and advocacy by the expert witnesses for their client. The objectives of the paper include improvement of readers’ appreciation of the concepts of objectivity, bias and advocacy, and the need to emphasize the importance of diversity of opinion in the resolution of disputes.