Our courts were not designed to consider the increasingly complex scientific and technical evidence needed to resolve contemporary legal disputes. Moreover, when conflicting evidence requires an understanding and interpretation of scientific or technical issues, allowing the parties to control the presentation of evidence places great strain on the judge and jury. This essay describes and evaluates three prototypical procedures that allow courts to appoint scientists and other experts independent of the parties to assist the court: 1) The appointment of an expert to advise the court and the parties regarding a disputed scientific issue by testifying in open court and being cross-examined by the parties; 2) The appointment of a “technical advisor” who assists the judge regarding scientific issues in much the same way that a law clerk assists regarding legal issues; and 3) The appointment of a special master who takes responsibility for the resolution of a portion of the case and prepares a written report for consideration by the court.
Our courts were not designed to consider the increasingly complex scientific and technical evidence needed to resolve contemporary legal disputes. The common law tradition of the United States relies on the litigating parties to structure the presentation of evidence by selecting witnesses and allows them in some measure to shape their evidence presentation to their own advantage. While there are limits on the extent to which this can be done with ordinary witnesses, there is far greater leeway in shaping the evidence presented by expert witnesses. Indeed, if a party does not like what one retained expert has to say, the party need not call that expert and can instead present another expert whose testimony better supports the party’s case. In most instances, the opposing side and the factfinder will not even know that another expert had been consulted. Similarly, cross-examination by the opposing party is supposed to identify weaknesses in opposing witness testimony by revealing inconsistencies, showing flaws in opportunities to observe, and revealing biases and other motives to deceive. Juries and judges are expected to understand the points being made. Experts, however, typically know considerably more than opposing counsel about the matters they discuss in their testimony, and jurors and judges typically know even less. Some experts are experienced witnesses selected in part for their proven success in withstanding cross-examination and persuading judges and jurors to their side. Others may be novices, inexperienced in giving testimony, who communicate poorly to the jury or are easily flustered by a cross-examiner, even if their science is sound. . . .