Legal Definitions - Frye test

The Frye test was a legal standard formerly used in federal courts, and still applied in some state courts, to determine whether scientific evidence or expert testimony was admissible in a trial. Its primary requirement was that the scientific method, theory, or technique presented by an expert witness must have gained "general acceptance" within its particular scientific field.

This standard originated from the 1923 case of Frye v. United States. Under the Frye test, a judge's role was to act as a gatekeeper, ensuring that only scientific evidence considered reliable by the relevant scientific community could be presented to a jury. At the federal level, the Frye test was replaced in 1993 by the Daubert test, which established a different set of criteria for admissibility based on the Federal Rules of Evidence.

Here are some examples illustrating how the Frye test would apply:

• Early Voiceprint Analysis: Imagine a criminal trial in the 1970s where the prosecution seeks to introduce expert testimony identifying a defendant through a "voiceprint" analysis, claiming it matches a recording from the crime scene. Under the Frye test, the court would need to determine if the scientific community specializing in acoustics, phonetics, and forensic voice analysis generally accepted voiceprint identification as a reliable and valid method for individual identification at that time. If the technique was still considered experimental or lacked widespread endorsement among these experts, the evidence would likely be excluded.

  This illustrates the Frye test because the court's decision hinges on whether the specific scientific technique (voiceprint analysis) had achieved broad consensus and acceptance within its relevant scientific field.

• Novel Psychological Profiling: Consider a civil case where an expert psychologist proposes to testify about a defendant's state of mind using a newly developed psychological profiling technique that has only been published in a single, obscure journal and has not undergone extensive peer review or replication studies. If a court were applying the Frye test, it would inquire whether this novel profiling method was generally accepted as a reliable diagnostic or analytical tool by the broader community of forensic psychologists and psychiatrists. If the technique was not widely recognized or accepted as scientifically sound by the relevant experts, the psychologist's testimony based on it would be deemed inadmissible.

  This example demonstrates the Frye test's focus on the scientific community's consensus regarding the reliability of a new methodology before it can be presented as evidence in court.

• Unproven Forensic Chemical Detection: Suppose in a product liability lawsuit, the plaintiff's expert witness wants to present findings from a brand-new laboratory method for detecting trace amounts of a specific chemical contaminant. This method was developed by the expert's private lab and has not yet been peer-reviewed, published in major scientific journals, or adopted by other forensic or analytical chemistry labs. A court applying the Frye test would evaluate whether this novel chemical detection method had gained general acceptance among analytical chemists, toxicologists, or other relevant scientific experts as a reliable and accurate technique. Without such widespread acceptance, the expert's testimony relying on this unproven method would likely be excluded.

  This scenario highlights how the Frye test acts as a gatekeeper, preventing the introduction of scientific techniques that are not yet validated and broadly accepted by the scientific community.