The Daubert Motion

There is no Daubert motion in the Federal Rules

The phrase is practitioner shorthand and it names an argument rather than a procedural device. No Federal Rule of Civil Procedure or Evidence creates a motion by that name. A challenge to expert testimony under FRE 702 is brought as one of the following:

• a motion in limine, the usual vehicle;
• a motion to exclude or to strike the opinion or the report;
• part of a summary-judgment motion, where exclusion of the opinion is dispositive of an element;
• an objection at trial, preserved and renewed; or
• a post-trial motion, where the point has been preserved.

Because the rule text now carries the standard, some commentators argue the label should be retired in favor of “Rule 702 motion.” That is more than a naming preference. A motion framed around a thirty-year-old opinion invites a response built on thirty years of gloss; a motion framed around the current text of the rule puts the four requirements and the burden in front of the court in the words the court has to apply.

The label also survives in local rules and standing orders, several of which use it explicitly. Where the assigned judge’s order uses the term, use the term.

What the motion actually puts in issue

The motion does not carry a burden of proving the testimony inadmissible. It puts the requirements of the rule in issue, and once they are in issue the proponent must establish each of them by a preponderance. The current text, effective 1 December 2023, states the allocation on the face of the rule:

“A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if the proponent demonstrates to the court that it is more likely than not that: (a) the expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue; (b) the testimony is based on sufficient facts or data; (c) the testimony is the product of reliable principles and methods; and (d) the expert’s opinion reflects a reliable application of the principles and methods to the facts of the case.”

That allocation is not new. FRE 104(a) always supplied it, and the 2000 Advisory Committee Note said so: “the proponent has the burden of establishing that the pertinent admissibility requirements are met by a preponderance of the evidence.” The 2023 amendment exists because many courts had not applied it — the Committee wrote that holdings treating the sufficiency of an expert’s basis and the application of the methodology as questions of weight “are an incorrect application of Rules 702 and 104(a).” A motion drafted against the current text should say which subsection each challenged opinion fails, and why. Rule text and Notes: FRE 702.

Timing, and the deadline that quietly controls everything

The sequence begins with disclosure. FRCP 26(a)(2)(B) requires a written report from a retained expert; FRCP 26(a)(2)(D) supplies default timing of 90 days before trial, and 30 days after the opposing disclosure for a rebuttal expert, absent stipulation or court order. The deposition follows.

Most districts then set a separate expert-challenge deadline in the FRCP 16(b) scheduling order, frequently keyed to the close of expert discovery rather than to the trial date, and frequently earlier than counsel expect. Filing after it commonly waives the challenge, and the risk is real enough that the deadline should be diaried when the scheduling order issues rather than when the report arrives.

Two timing choices follow from that. First, whether to depose the expert early enough to leave drafting time — a motion built without deposition admissions is a motion built on the report alone, and reports are drafted to survive. Second, whether to move together with summary judgment. Where exclusion of a causation or damages opinion would leave an element unsupported, the two motions are usually briefed as one package, and the court then has a reason to reach the expert question first.

What the papers have to contain

The national rules say nothing about the contents of the motion. Local rules and the individual judge’s standing order control, and they are more specific than most practitioners assume. A representative standing order in the Northern District of Illinois requires the movant to identify the specific opinions sought to be excluded and the legal basis for exclusion, “together with sufficient background information to provide context”; to file the relevant expert reports and, where the expert was deposed, the full transcript in searchable format; provides that the court may conduct a hearing on request or on its own; and states expressly that the proponent bears the burden of demonstrating that the testimony satisfies the standard.

Three drafting consequences are worth naming. Identify opinions, not witnesses. Courts routinely admit part of an expert’s testimony and exclude the rest, and a motion that asks for wholesale exclusion of a qualified witness often gets nothing. Quote the record. A reliability argument that rests on characterization rather than on transcript pages invites the answer that the movant has described the method inaccurately. Match each argument to a subsection. An objection to the data is a 702(b) objection; an objection to the method is 702(c); an objection to how the method was used here is 702(d); an objection to the fit between the opinion and the issues is 702(a).

Where the record comes from

Because FRE 104(a) frees the court from the rules of evidence in deciding a preliminary question, the material available on the motion is broader than what could be shown to a jury. The report, the deposition transcript, an unsworn declaration and the underlying literature are all properly before the court.

In practice the deposition is where the motion is made or lost. What a brief needs is not an expert who says something foolish but an expert who has confirmed, under questioning, what was and was not done: which data were considered and which were set aside, what alternatives were ruled out and on what basis, what the method would have produced if applied consistently, and where the conclusion goes beyond what the analysis supports.

That produces a genuine strategic fork. The questions that build the record are the same questions that tell the opposition what the motion will say, and an exposed gap left uncured hands the proponent months to supplement, reframe or retain another witness, subject to the disclosure deadlines. Counsel who intend to move usually accept that cost, because a motion unsupported by deposition admissions is generally decided against the movant. Counsel who intend only to cross-examine at trial have the opposite incentive.

Answering one

The response is written to the same four subsections, and there are two arguments that a proponent should be careful about.

The first is “that goes to weight.” The category still exists — the Committee gave the example of an expert who has not read every study, which raises a question of weight once the court has found a sufficient basis — but it is narrower than the pre-2023 case law suggests, and citing a circuit decision that treats basis or application as automatically a weight question is now an invitation for the movant to quote the Committee Note against it.

The second is over-defending the conclusion. The proponent does not have to show that the opinion is correct. “The evidentiary requirement of reliability is lower than the merits standard of correctness,” and the Rule 104(a) standard “does not require perfection” and does not oblige a court to “nitpick an expert’s opinion.” A response that walks the court through what the method is, that it is used outside litigation, that it was applied to these facts, and where its limits were disclosed will usually do more than a defense of the result.

Where the court is being asked to resolve a genuine factual dispute between two qualified experts, the Committee’s own answer is available: by deciding the disputed facts, the jury can decide which side’s experts to credit.

What the motion usually achieves

Exclusion in whole is the exception. The common outcomes, in descending order of frequency, are narrowing of the opinion, a limitation on how a conclusion may be stated, concessions in the opposition brief that constrain the trial testimony, and a cross-examination outline that would not otherwise exist. A motion that is denied still forces the proponent to commit in writing to what the methodology is, and the judge who denies it has read the weaknesses.

Reported success rates should be handled carefully. Figures in circulation range from roughly a quarter to roughly two-thirds, and the range is an artifact of what is counted — challenges filed or written opinions, full exclusion or partial exclusion, which subject matter, and who is doing the counting. The RAND Institute for Civil Justice study by Lloyd Dixon and Brian Gill (2002) coded 399 federal district court opinions from 1980 to 1999 and reported the share of challenged evidence found unreliable rising from about 53 percent before 1993 to about 70 percent by 1996–97, on a denominator of written opinions addressing reliability rather than all challenges. PwC’s annual study of challenges to financial experts reported full or partial exclusion of appraisers in 38 percent, accountants in 32 percent and economists in 27 percent of challenges in 2021 — and PwC’s forensic practice supplies financial expert witnesses. There is no reliable single national figure, and any number should be traced to its denominator before it is repeated.

After the ruling

A ruling on a motion in limine may be provisional. Where it is, the objection has to be renewed when the evidence is offered; where the court has ruled definitively on the record, FRE 103(b) relieves a party of the need to renew it in order to preserve the point. Which kind of ruling was made is worth clarifying on the record before trial.

On appeal the standard is abuse of discretion under General Electric Co. v. Joiner, 522 U.S. 136 (1997), and under Kumho Tire that deference reaches the trial court’s decisions about how to test reliability as well as its ultimate conclusion. The practical asymmetry is worth stating: a district court that excludes an opinion and makes specific findings element by element is in a strong position on appeal, and a court that admits an opinion without any findings is not — at least in circuits following the Tenth Circuit’s line in Dodge v. Cotter Corp., 328 F.3d 1212 (10th Cir. 2003), which requires a record adequate to show that the gatekeeping duty was performed.

That asymmetry is also the reason a movant who loses should ask for findings rather than a docket entry, and the reason a proponent who wins should be content with either. Opinion text: Joiner, 522 U.S. 136.

Frequently Asked Questions

Published 2026-08-12