The difference between the Frye standard and the Daubert standard comes down to who decides whether expert testimony is reliable enough for a jury to hear. Under Frye, a scientific technique is admissible only if it is generally accepted by specialists in the relevant field. Under Daubert, the trial judge acts as a gatekeeper and evaluates the methodology directly using several factors, of which general acceptance is only one. Every federal court uses Daubert, a majority of states have adopted it, and a handful of states still apply Frye.
What Frye Requires
The Frye standard comes from a 1923 decision of the D.C. Circuit Court of Appeals, Frye v. United States, 293 F. 1013. The court rejected expert testimony based on an early polygraph technique, holding that the method had “not yet gained such standing and scientific recognition among physiological and psychological authorities” to justify admitting it.1Court of Appeals of the District of Columbia. Frye v. United States, 293 F. 1013 (D.C. Cir. 1923)
That reasoning became the rule. Expert testimony based on a scientific technique is admissible only if the technique is generally accepted as reliable by the relevant scientific community. “Generally accepted” does not mean universally embraced. It means a meaningful consensus among specialists in the particular field, and the test focuses on the methodology itself rather than the conclusions the expert draws.
Frye’s appeal is its simplicity. The judge does not have to evaluate the science independently; the reliability question is effectively outsourced to the scientific community. If most qualified scientists in the field accept the technique, it comes in. If not, it stays out. The trade-off is that a reliable technique can be excluded because the field has not caught up to it yet.
What Daubert Requires
In 1993, the Supreme Court replaced Frye as the federal standard in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579. The Court held that the Federal Rules of Evidence, not Frye’s general acceptance test, govern the admission of expert testimony in federal court. Before an expert testifies in front of a jury, the trial judge must make a preliminary determination that the underlying reasoning or methodology is scientifically valid and properly applied to the facts.2Cornell Law School Legal Information Institute. Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579 (1993)
The Court identified several factors judges should weigh:
- Whether the theory or technique can be tested, and whether it has been.
- Whether the work has been subjected to peer review and publication.
- The known or potential rate of error.
- Whether standards controlling the technique’s operation exist and are maintained.
- Whether the technique is generally accepted in the relevant scientific community.
General acceptance survives under Daubert, but as one factor among several rather than the whole test. A technique too new to have achieved broad consensus can still be admitted if it holds up on the other factors. A widely accepted method can be excluded if it was applied sloppily or its error rate is unacceptably high for the case at hand.
The Two Follow-Up Cases That Shaped Daubert
Two later Supreme Court decisions round out what lawyers call the “Daubert trilogy.”
General Electric Co. v. Joiner (1997)
In General Electric Co. v. Joiner, 522 U.S. 136, the Court held that appellate courts review a trial judge’s gatekeeping decision only for abuse of discretion. An appeals court will not overturn the ruling just because it would have decided differently. Joiner also recognized the “analytical gap” problem: a judge may exclude expert testimony when the gap between the underlying data and the expert’s conclusion is too wide. Nothing in Daubert or the Federal Rules, the Court said, “requires a district court to admit opinion evidence that is connected to existing data only by the ipse dixit of the expert.”3Justia U.S. Supreme Court Center. General Electric Co. v. Joiner, 522 U.S. 136 (1997)
Kumho Tire Co. v. Carmichael (1999)
Daubert spoke in terms of “scientific” knowledge, leaving open whether the same gatekeeping obligation applied to engineers, accountants, and other experts working from technical or experience-based knowledge. In Kumho Tire Co. v. Carmichael, 526 U.S. 137, the Court answered yes. The gatekeeping duty applies to all expert testimony under Rule 702, whether scientific, technical, or otherwise specialized. A trial judge can apply the Daubert factors, adjust them, or use different criteria altogether, whatever fits the discipline.4LII Supreme Court. Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999)
The 2023 Update to Rule 702
Federal Rule of Evidence 702 has been the statutory backbone of the Daubert framework since 2000. An amendment that took effect in December 2023 sharpened the burden of proof. The rule now states that an expert may testify only if “the proponent demonstrates to the court that it is more likely than not” that the testimony meets each admissibility requirement.5Legal Information Institute. Federal Rules of Evidence Rule 702 – Testimony by Expert Witnesses
The change was needed because many courts had been treating questions about the sufficiency of an expert’s basis and the soundness of the methodology as questions of “weight” for the jury rather than “admissibility” for the judge. The advisory committee called that an incorrect application of the rules. The party offering the expert now bears the burden of showing, before the testimony reaches the jury, that each reliability requirement is more likely satisfied than not.5Legal Information Institute. Federal Rules of Evidence Rule 702 – Testimony by Expert Witnesses
Under the current text, the proponent must show four things: that the expert’s knowledge will help the jury understand the evidence or decide a fact in issue, that the testimony is based on sufficient facts or data, that it is the product of reliable principles and methods, and that the expert reliably applied those methods to the facts of the case.5Legal Information Institute. Federal Rules of Evidence Rule 702 – Testimony by Expert Witnesses
How the Standards Differ in Practice
The core difference is who decides and how. Under Frye, the scientific community effectively controls admissibility. The judge’s role is comparatively passive: if most specialists accept the technique, it comes in; if they do not, it stays out. Under Daubert, the judge independently evaluates the methodology using multiple criteria. That is a fundamentally different exercise, and it changes strategy for both sides.
Frye’s simplicity is an advantage with settled science. Nobody seriously disputes DNA analysis or blood-alcohol testing, and a general acceptance test handles those efficiently. Where Frye struggles is with newer or evolving methods. A technique can be sound and highly accurate yet fail Frye because the relevant professional community has not reached consensus. That criticism is what pushed federal courts toward Daubert.
Daubert opens the door wider for novel scientific evidence, but it also hands opponents more angles of attack. A party can argue the methodology has not been tested, that the error rate is too high, that the expert failed to follow the field’s own standards, or that the conclusions do not follow from the data. Under Frye, the challenge is essentially binary: is the method generally accepted, or is it not?
That distinction has real consequences in forensic science. Techniques such as bite-mark comparison and microscopic hair analysis have faced heavier scrutiny in Daubert jurisdictions, where opponents can attack error rates and the absence of standardized protocols. In Frye jurisdictions, the same techniques may survive challenge more easily if the relevant professional community still endorses them.
How a Challenge Actually Plays Out
A Daubert challenge usually takes the form of a motion in limine, a pretrial request asking the judge to exclude or limit specific expert testimony. These motions are typically filed after discovery closes, once each side knows which experts the other plans to call and what opinions they will offer.
The judge holds a hearing outside the jury’s presence. The party offering the expert bears the burden of showing that the testimony meets Rule 702. The challenging party argues that the methodology is unreliable, the qualifications are insufficient, or the opinions do not fit the facts. The judge may review the expert’s report, deposition testimony, underlying studies, and rebuttal materials.
After the hearing, the judge issues a ruling. The testimony may be admitted in full, admitted with limits (for example, the expert can offer some opinions but not others), or excluded entirely. Because appellate review is deferential under Joiner, the trial court’s decision carries enormous weight, and getting the challenge right at that stage is often decisive.
In Frye jurisdictions, a similar pretrial motion (sometimes called a Frye motion or Frye hearing) serves the same gatekeeping function, but the inquiry is narrower. It usually focuses on what the consensus view is, often through testimony from other experts in the field.
Which Standard Applies Where
Every federal court follows Daubert, reinforced by Rule 702 and the trilogy.2Cornell Law School Legal Information Institute. Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579 (1993) A majority of states have adopted Daubert or something closely modeled on it.
A small number of states still apply the Frye general acceptance test, including California (which uses a variant called Kelly/Frye), Illinois, New York, Pennsylvania, Washington, and North Dakota. Roughly a dozen other states use hybrid approaches or state-specific standards that do not map neatly onto either framework. Some of those hybrids apply Daubert-like factors while keeping general acceptance as the primary test; others have developed their own multi-factor analyses through case law or statute.
If your case is in state court, the applicable standard depends on the state. If your case is in federal court, Daubert governs regardless of the surrounding state’s rule. That split can matter when choosing where to file, because the same expert testimony might be admissible in one court and excluded in another based solely on which standard applies. Lawyers in Frye states sometimes move cases to federal court to take advantage of Daubert’s broader framework for novel evidence, and the reverse happens too.