The Frye Standard in Expert Testimony

Within United States jurisprudence, there are generally two major competing standards which are based on two seminal decisions – a D.C. Circuit case, Frye v. United States, 293 F. 1013 (D.C. Cir. 1923), and a U.S. Supreme Court decision, Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993). While the federal court system exclusively follows Daubert, state courts are divided between the two. A number of states continue to use the Frye standard, and interestingly, the states that have adopted the Daubert standard (approximately 27) have not all uniformly applied the standard.

In light of the differences between Daubert and Frye, challenging and defending expert admissibility must be tailored to fit the governing standard. When seeking to admit expert testimony under Frye, the expert’s opinion must be “generally accepted” within its scientific community. The “general acceptance test,” to which Frye is most often referred, presents its own set of questions to analyze when determining admissibility. A successful argument under Frye should take into consideration certain key points of the standard.

What is the Frye Standard?

The general premise in Frye v. United States, 293 F. 1013 (D.C. Cir. 1923) states that an expert opinion is admissible if the scientific technique on which the opinion is based is “generally accepted” as reliable in the relevant scientific community.

In Frye, the Circuit affirmed the trial court’s decision to expert testimony concerning a lie detector test. The test, which was based on changes in systolic blood pressure, was considered to have “not yet gained such standing and scientific recognition among physiological and psychological authorities.” As the Frye court describes:

The rule is that the opinions of experts or skilled witnesses are admissible in evidence in those cases in which the matter of inquiry is such that inexperienced persons are unlikely to prove capable of forming a correct judgment upon it, for the reason that the subject matter so far partakes of a science, art, or trade as to require a previous habit or experience or study in it, in order to acquire a knowledge of it.

When the question involved does not lie within the range of common experience or common knowledge but requires special experience or special knowledge, then the opinions of witnesses skilled in that particular science, art, or trade to which the question relates are admissible in evidence. See Frye, at 1113.

Evolution and Impact

Just when a scientific principle or discovery crosses the line between the experimental and demonstrable stages is difficult to define. Somewhere in this twilight zone, the evidential force of the principle must be recognized, and while the courts will go a long way in admitting expert testimony deduced from a well-recognized scientific principle or discovery, the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs. Id. at 1014.

Although Frye was decided in 1923, for decades it was not widely followed – the case was not cited for over 10 years following the decision. The standard was increasingly used in the 1970s, predominantly in criminal cases, and then made its way into civil cases, such as toxic torts. Eventually, it became the governing standard of expert admissibility, albeit, a broad one.

The standard set forth in Frye is applied to new or novel scientific techniques to determine whether the principles are accepted in the relevant scientific community. But what is general acceptance? It has been defined in vastly different ways, from “widespread; prevalent; extensive, though not universal” to a finding that applies a “substantial section of the scientific community.”

More than 50 years after the Frye holding, Congress enacted the Federal Rules of Evidence, with Rule 702 providing guidance as to the admissibility of experts. The first version of Rule 702 of the Federal Rules of Evidence provided that: “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.” The Rule failed to specify whether it superseded Frye, and as such, the general acceptance test continued to act as the governing standard.

Junk Science Under Frye

Prior to Frye v. United States, experts and their testimony weren’t always subjected to an admissibility test. When they were, the test was often pragmatic, even economic in nature: The witness was an “expert” if they could make a living doing what they did. If a specialized issue in that field arose, the witness could testify not only to facts but also to opinions informed by their profession.

In 1923, Frye focused on the use of blood pressure-based lie detector tests. The court affirmed that “experts or skilled witnesses” and their opinions were admissible in cases in which “inexperienced persons are unlikely to prove capable of forming a correct judgment,” because the subject matter is arcane, complex, or specific.

Frye gave judges considerable leeway in deciding which types of experts and expert testimony would be allowed in a particular case. However, the court set one standard: “the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs.”

Key Differences Between Frye and Daubert Standard

As the Frye standard gained momentum despite Rule 702, so did its criticisms. Some commentators believed that Frye was too vague, and incorrectly assumed that the scientific community will always test new scientific techniques before applying them. A major difference between Daubert and Frye is that Frye focuses on "general acceptance" within the scientific community, whereas Daubert emphasizes "relevance and reliability". In the context of these criticisms, the standard set forth in Daubert emerged.

In Daubert v. Merrell Dow Pharmaceuticals, Inc., the Supreme Court overruled Frye in federal courts, holding that the case law was inconsistent with Rule 702 of the Federal Rules of Evidence. In Daubert, the Court held that the twin standards of Rule 702 – relevance and reliability – are incompatible with the stricter “general acceptance” test. The Court emphasized the importance of a trial judge’s “gatekeeping responsibility” when admitting expert testimony and listed a non-exhaustive list of factors to consider such as:

1. Whether the expert’s technique or theory can be tested and assessed for reliability
2. Whether the technique or theory has been subject to peer review and publication
3. The known or potential rate of error of the technique or theory
4. The existence and maintenance of standards and controls
5. Whether the technique or theory has been generally accepted in the scientific community

What to Expect in a Hearing Under Frye

When an adversary challenges the admissibility of expert testimony in a Frye jurisdiction, it is important to remember this is much more limited than the analysis that occurs at a Daubert hearing. That is, the only inquiry for the court is whether the techniques used by the expert are generally accepted as reliable within its scientific community. A Frye hearing is also much more limited in that it applies only to novel scientific evidence.

Because a Frye inquiry essentially focuses on one factor – general acceptance – a hearing may be unnecessary where judicial precedent establishes that certain scientific techniques were previously accepted as reliable within the community.

Universal acceptance by the scientific community is not a prerequisite to admissibility, but rather, that there is proof that a technique generates reliable results. See People v. Middleton, 54 N.Y.2d 42, 49 (1981) (“But the test is not whether a particular procedure is unanimously endorsed [sic] by the scientific community, but whether it is generally acceptable as reliable.”). Under Frye, general acceptance can be shown in an array of ways, such as through “scientific publications, judicial decisions, or practical applications.”

When a trial court conducts a Frye hearing, it is only determining whether the expert’s techniques are generally accepted by the scientific community. Issues such as whether the expert’s conclusions are reliable or relevant are separate and distinct from such an inquiry.

In light of the pointed focus of the Frye general acceptance test, it is important to tailor one’s expert testimony to this specific factor. If it can be established that an expert’s opinion is generally accepted within its own scientific community, the testimony will stand a greater chance of surviving any challenges.