Admissibility of Scientific Evidence
Only admissible evidence is used in court proceedings, but what determines admissibility? Admissibility of evidence is regulated by the Federal Rules of Evidence. These rules were developed in 1973 and govern the introduction of evidence in civil and criminal proceedings. The Federal Rules of Evidence incorporate the judge-made decisions and common evidentiary rules that were in effect at the time of their adoption. If the Federal Rules contain gaps or omissions, courts may answer questions by relying on a precedent. The factors that deem evidence inadmissible include prejudice, unreliability, and privilege. Evidence that causes prejudice includes anything that could turn the triers of fact against the accused. Examples of prejudicial evidence include graphic images of a victim presented by color photographs or facts that highlight a prior incident, not for which the accused is currently being tried. Unreliable evidence includes eyewitness testimony, hearsay, or evidence that has not gone through the process of discovery. Privilege could affect the admissibility of evidence because in cases of attorney-client or doctor-patient privilege, protection is offered from having to offer testimony on persons or information that is considered confidential.
Federal Rule 702, “Testimony by Experts,” says, “If scientific, technical, or other specialized knowledge will assist the triers 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, if (1) the testimony is based upon sufficient facts or data,
(2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case.” (Federal Rules of Evidence 702, 1988; emphasis added by the author)