Definition

Admissibility of evidence refers to any testimonial, documentary material, or other form of tangible evidence that can be considered by the trier of fact, most typically a judge or a jury, in the context of a judicial or administrative proceeding. In order for evidence to be admissible, it must be relevant, non-prejudicial, and possess some indicia of reliability. For example, if evidence consists of a witness testimonial, it must be established that the witness is credible and that he/she has knowledge of that which he/she is declaring. For neuropsychologists, a central issue is the admissibility of one’s data and opinions. Rules 401, 402, and 702–705 from Article VII of the Federal Rules of Evidence (FRE) relate to “Opinions and Expert Testimony.” Perhaps of most relevance to psychologists is rule FRE 702 which states, “If scientific, technical, or other specialized knowledge will assist the trier of fact 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 other words, the expert should possess some form of knowledge that a typical judge or juror would not be expected to know or understand. Rule 703 states, “The facts or data in the particular case upon which an expert bases an opinion or inference may be those perceived by or made known to the expert at or before the hearing. If of a type reasonably relied upon by experts in the particular field in forming opinions or inferences upon the subject, the facts or data need not be admissible in evidence in order for the opinion or the inference to be admitted. Facts or data that are otherwise inadmissible shall not be disclosed to the jury by the proponent of the opinion or inference unless the court determines that their probative value in assisting the jury to evaluate the expert’s opinion substantially outweighs their prejudicial effect.”

Several important cases have addressed the admissibility of scientific testimony. In the case of Frye v. United States (1923), the Frye standard was established which stated that only scientific methods and concepts with “general acceptance” within a particular field are admissible. In the more recent case of Daubert v. Merrell Dow (1993), it was determined that scientific testimony has to abide by two criteria; the testimony must be (a) scientifically valid and (b) relevant to the case at hand.

Cross-References