Admitting Expert Testimony Under the Frye Standard: The Ultimate Guide


The Frye Standard Ultimate Guide

In order to ensure the admissibility of expert testimony, it is critical to understand the governing standard of expert admissibility in the jurisdiction in which the case will be tried.

Within United States jurisprudence, there are generally two major competing standards which are based in 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 Daubert (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.

The History of 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.

As the Court in Frye holds:

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.

Frye v. Daubert: Key Differences

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. In the context of these criticisms, the standard set forth in Daubert emerged.

In Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993), 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

Under this new standard, the Court encouraged a more liberal approach to admitting expert testimony, stressing the importance of subjecting witnesses to vigorous cross-examination instead. The decision in Daubert to relax the admissibility standards of expert testimony was further expounded by its progeny. In General Electric Co. v. Joiner, 522 U.S. 136 (1997), the Court emphasized the importance of expert methodology, opposed to focusing solely on the conclusory opinion, finding that “conclusions and methodology are not entirely distinct from one another.”

Less than one year after Joiner was decided, the Supreme Court held in Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999) that the Daubert standard applies to expert testimony that is not scientific in nature, broadening the range of evidence to which Daubert applies. The Court found no relevant distinction between experts who rely on scientific principles and those who rely on “skill- or experienced-based observation,” citing Rule 702 of the Federal Rules of Evidence, which also makes no distinction between scientific knowledge and “technical or other specialized knowledge.”

In order to argue admissibility under Frye, it is critical to understand its differences with Daubert. The most obvious difference between Frye and Daubert is the broadened approach of the latter. While Frye essentially focuses on one factor – whether the expert’s opinion is generally accepted by the relevant scientific community – Daubert offers a list of factors to consider. By defining the function of trial judges as “gatekeepers,” Daubert encourages judges to determine admissibility, while Frye focuses on the expert’s own scientific community.

A Hearing Under Frye: What to Expect

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. See Krackmalnik v. Maimonides Med. Ctr., 142 A.D.3d 1143,1144 (2d Dept. 2016) (“Here, the opinion of plaintiff’s expert was not based on novel theories and did not warrant a preliminary Frye-type hearing.”).

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. See People v. LeGrand, 8 N.Y.3d 449, 458 (2007) (“A court need not hold a Frye hearing where it can rely upon previous rulings in other court proceedings as an aid in determining the admissibility of the proffered testimony.”)

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 indorsed [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.

About The Author

Anjelica Cappellino, J.D. is an accomplished defense attorney and legal writer who has represented numerous federal criminal defendants in the Southern and Eastern Districts of New York.