As scientific and forensic evidence advancements have become more and more sophisticated, the employment of expert witnesses to present scientific opinions interpreting this evidence has become an essential element in criminal justice legal proceedings. The use of expert witnesses by both prosecution and defense counsel has become a common, if not integral, part in presenting matters to the court that are generally dispositive of the ultimate question of guilt or innocence in criminal matters.
In maintaining a contemporary approach to keep pace with these scientific and forensic changes, the U.S. Supreme Court has issued several significant opinions in recent years that offer insight into the admission of such opinion testimony as evidence as well as the weight and credibility to be given to expert witness testimony. In a similar approach to insure consistent and current use and applicability of expert witness testimony, Congress, with the approval of the Supreme Court, has made recent amendments to the Federal Rules of Evidence on that subject matter and legal issue.
Expert witnesses, their case evaluations and solicited opinions, as well as their testimonies in court, have become extremely critical in determining the outcome of criminal case prosecutions and in some instances post-conviction appellate relief. Furthermore, expert witness testimony has often been a dominant factor in determining liability or lack thereof in civil lawsuits in state and federal litigation against public entities, law enforcement agencies and individual peace officers where there are allegations of abuse of official authority and civil rights violations.
The Court of Appeals for the District of Columbia first addressed the issue of the admissibility of scientific expert witness testimony in 1923 in Frye v. United States, 293 F. 1013 (D.C. Cir. 1923) and the impact of such expert witness testimony and evidence in federal court proceedings. This case, which dealt with the admissibility of polygraph test results, was decided before the adoption of the Federal Rules of Evidence some 50 years subsequent to this decision.
The court in Frye, supra, established the "general acceptance" of a scientific theory in a specifically material and relevant field of expertise as an essential prerequisite for the use and admission of such expert scientific evidence and testimony in federal court proceedings. In 1974, Congress, with the approval of the Supreme Court, enacted the Federal Rules of Evidence.
Rule 702 specifically governs the admissibility of expert witness testimony, "if scientific, technical, or other specialized knowledge will assist the trier of fact (judge/jury) to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education may testify thereto in the form of an opinion or otherwise."
In 1993, the Supreme Court in Daubert v. Merrell Dow Chemicals, Inc., 509 U.S. 579 (1993), reviewed Rule 702 in light of the previous decision in Frye, supra, and for all practical purposes changed the standard used to evaluate the admissibility of scientific expert witness testimony in federal court proceedings. The test established in Daubert, supra, for purposes of admissibility as evidence, required that any expert witness scientific testimony be supported by "appropriate validation" or "good grounds," and meet the requirements of Rule 702 that such evidence or testimony assist the trier of fact to understand evidence, determine facts at issue in trial proceedings, and meet traditional evidentiary standards for relevance and materiality.
For all practical purposes, the "general acceptance" standard established in Frye, supra, was determined to be inapplicable and legislatively over-ruled by Congress with the enactment of the Federal Rules of Evidence and their specific provisions regarding scientific expert witness …