Daubert vs. Frye: What’s the Difference?

Daubert and Frye are two competing legal standards for admitting expert testimony. The Daubert standard, from Daubert v. Merrell Dow Pharmaceuticals (1993) and codified in Federal Rule of Evidence 702, asks whether an expert’s methods are reliable and relevant. The older Frye standard asks only whether the methods are generally accepted in their field.

This article compares the two tests, traces each to its origin and maps which jurisdictions apply which standard. For any litigator who retains or challenges experts, the distinction shapes how a case must be prepared long before trial.

What Is the Difference Between Daubert and Frye?

The core difference is that Daubert makes the trial judge a gatekeeper who evaluates an expert’s methodology directly, while Frye defers to whether the relevant scientific community generally accepts that methodology. Under Frye, a judge counts the field’s consensus. Under Daubert, a judge assesses reliability itself, considering factors like testing, peer review, error rates and general acceptance among others. Daubert is therefore broader and more searching: general acceptance is one factor rather than the whole inquiry.

That shift changes the practical burden. Frye can admit a well-accepted technique with little independent scrutiny and exclude a novel one regardless of its soundness. Daubert lets a judge admit a new but reliable method and exclude an accepted but flawed one. The proponent of expert testimony carries the burden of establishing admissibility under either standard, but the target differs: under Frye the proponent documents consensus, while under Daubert the proponent must defend the method itself. That difference dictates how experts are prepared, what materials they must cite and how a challenge is framed.

What Is the Daubert Standard?

The Daubert standard directs trial judges to admit expert testimony only if it rests on reliable principles and methods reliably applied to the facts. The Supreme Court announced it in 1993, holding that the Federal Rules of Evidence — not the old Frye test — governed expert admissibility in federal court. The Court offered a non-exclusive list of reliability factors and assigned the judge a gatekeeping role, later extended to all expert testimony, not just scientific evidence, in Kumho Tire Co. v. Carmichael (1999).

Daubert’s factors are flexible guideposts rather than a checklist. A judge weighs them as the field and the testimony warrant, and the analysis now lives in Federal Rule of Evidence 702, which the 2000 and 2023 amendments refined. The inquiry is central in cases turning on complex causation, such as product liability and medical malpractice claims.

• Whether the theory or technique can be, and has been, tested.
• Whether it has been subjected to peer review and publication.
• The known or potential error rate and the existence of standards controlling its operation.
• Whether it enjoys general acceptance in the relevant scientific community — one factor, not the test.

What Is the Frye Standard?

The Frye standard admits expert testimony only if the underlying principle or technique has gained general acceptance in the particular field to which it belongs. It comes from Frye v. United States, a 1923 decision of the D.C. Circuit that excluded early lie-detector evidence because the technique had not achieved acceptance among physiologists and psychologists. For seventy years, “general acceptance” was the dominant test in American courts.

Frye’s virtue is administrability: rather than resolving scientific disputes, the judge asks whether the relevant community has embraced the method. Its criticism is the mirror image — it can lag behind sound but novel science and rubber-stamp entrenched but questionable techniques. Frye focuses on the acceptance of the method, not the qualifications of the individual expert, which are addressed separately.

• The test asks about acceptance of the methodology, not the expert’s personal credibility.
• “General acceptance” does not require unanimity, but it demands more than a single proponent.
• The relevant field must be defined, which can itself be disputed.
• Novel techniques face a high bar until the field coalesces around them.

Which States Use Daubert and Which Use Frye?

Federal courts and a majority of states follow Daubert, while a minority retain Frye, and the alignment continues to shift. After the Supreme Court decided Daubert, most states adopted it or a close variant, and several longtime Frye jurisdictions have switched in recent years. Because a state can change its standard by decision or rule amendment, counsel should verify the current test in the governing jurisdiction rather than rely on a static list.

The practical consequence is significant for burden of proof on scientific issues. In a Daubert state, an early motion can force a full reliability hearing; in a Frye state, the fight centers on documenting acceptance in the field. Multistate litigation may require preparing an expert to satisfy both.

1. Federal courts apply Daubert through FRE 702 in all civil and criminal cases.
2. A majority of states have adopted Daubert or a substantially similar reliability standard.
3. A minority still apply Frye, historically including states such as California, Illinois, New York, Pennsylvania and Washington.
4. Several states, including Florida, have moved between the two in recent years, so the controlling standard should be confirmed case by case.

Conclusion

Daubert and Frye represent two philosophies of expert admissibility: Daubert asks the judge to test reliability directly, while Frye asks whether the field has generally accepted the method. Daubert now governs federal court and most states through FRE 702, but a meaningful minority retain Frye, and the map keeps changing as courts and legislatures act. For practitioners, the standard in play dictates how experts are selected, prepared and defended long before a witness takes the stand. Confirm the current test in your jurisdiction, because the difference between a reliability hearing and a consensus inquiry can decide whether key testimony ever reaches the jury.

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