A motion in limine is a broad pretrial request asking a judge to keep prejudicial evidence away from the jury, while a Daubert motion is a narrower challenge aimed only at the reliability of expert witness testimony. That’s the core of the Daubert motion vs. motion in limine comparison: both are filed before trial to stop the jury from hearing something that shouldn’t influence the verdict, but they rely on different rules of evidence and answer different questions. Filing the wrong one wastes time. Failing to file the right one lets damaging material into the record unchallenged.
What a Motion in Limine Does
A motion in limine (Latin for “at the threshold”) asks the judge to block certain evidence before anyone mentions it at trial. The idea is straightforward: once a jury hears that a defendant has five prior arrests, no instruction to “disregard that” truly erases it. Better to keep the material out in the first place.
These motions rest on Federal Rule of Evidence 403, which lets a court exclude relevant evidence when its value in proving a fact is substantially outweighed by the risk of unfair prejudice, jury confusion, or wasted time.1Cornell Law School. Federal Rules of Evidence Rule 403 – Excluding Relevant Evidence for Prejudice, Confusion, Waste of Time, or Other Reasons The judge weighs how much the evidence actually helps the jury understand the case against how likely it is to trigger an emotional reaction or send the jury down the wrong path.
The scope is wide. A plaintiff’s lawyer might move to exclude the plaintiff’s unrelated criminal history. A defense attorney might seek to keep out graphic photographs whose emotional impact vastly exceeds their factual value. The motion works for documents, photographs, physical objects, and testimony from ordinary witnesses. Its reach covers nearly any category of evidence.
What a Daubert Motion Does
A Daubert motion targets one specific kind of evidence: expert witness testimony. The name comes from the 1993 Supreme Court decision in Daubert v. Merrell Dow Pharmaceuticals, Inc., which held that trial judges must act as gatekeepers over expert evidence, screening out unreliable opinions before the jury hears them.2Justia Law. Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993) Six years later, Kumho Tire Co. v. Carmichael clarified that the duty extends to all expert testimony, not just opinions rooted in hard science.3Justia Law. Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999) Forensic accountants, vocational specialists, and accident reconstruction engineers all fall within the framework.
The judge’s focus is on the expert’s methodology, not the conclusion itself. The Supreme Court identified several factors to guide the analysis:2Justia Law. Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993)
- Whether the theory or technique can be tested, and has been.
- Whether it has been subjected to peer review and publication.
- The known or potential rate of error.
- Whether standards govern how the technique is applied.
- Whether the approach enjoys general acceptance in the relevant professional community.
These are guidelines rather than a rigid checklist. A judge has discretion to weigh them differently depending on the type of expertise involved.
The 2023 Amendment to Rule 702
Federal Rule of Evidence 702, which codifies the Daubert framework, was amended effective December 1, 2023. The change added explicit language requiring the party offering the expert to demonstrate that “it is more likely than not” that the testimony meets every admissibility requirement. The practical effect is significant. The amendment was a response to courts that had drifted toward a more permissive approach, treating shaky expert methodology as a matter of “weight” for the jury rather than admissibility for the judge. Under the amended rule, the proponent must show that the opinion is based on sufficient facts, uses reliable methods, and reliably applies those methods to the facts of the case.4Cornell Law School. Federal Rules of Evidence Rule 702 – Testimony by Expert Witnesses
How the Two Motions Relate
A Daubert motion is really a specialized form of motion in limine. Both ask the judge to exclude evidence “at the threshold,” before the jury hears it. The difference is which framework the motion invokes: a Daubert motion invokes Rule 702’s reliability standard for expert testimony, while a general motion in limine invokes the broader Rule 403 balancing test.
In the same lawsuit, an attorney might file a motion in limine to keep out settlement negotiations and a separate Daubert motion to challenge the opposing side’s biomechanical engineer. Both aim to exclude material before trial. They just use different tools to get there.
The Core Differences
What Each Motion Targets
A motion in limine can reach almost any evidence: documents, photographs, physical objects, lay witness statements, or entire topics of questioning. A Daubert motion applies exclusively to testimony from a designated expert witness. It has no application to ordinary fact witnesses or physical evidence.
The Legal Test
A motion in limine asks whether the evidence’s potential for unfair prejudice, confusion, or waste of time substantially outweighs its value in proving a relevant fact.1Cornell Law School. Federal Rules of Evidence Rule 403 – Excluding Relevant Evidence for Prejudice, Confusion, Waste of Time, or Other Reasons A Daubert motion asks a different question: is the expert’s methodology reliable enough that the opinion should be admitted at all? The first is a fairness balancing test. The second is a technical reliability assessment, where the judge acts under Rule 104(a) to decide a preliminary question of admissibility.5Cornell Law School. Federal Rules of Evidence Rule 104 – Preliminary Questions
Who Carries the Burden
On a motion in limine, the party seeking exclusion argues that the evidence fails the Rule 403 balancing test. On a Daubert motion, the burden falls on the party offering the expert to prove that the testimony satisfies Rule 702’s reliability requirements by a preponderance of the evidence.4Cornell Law School. Federal Rules of Evidence Rule 702 – Testimony by Expert Witnesses The side trying to admit the expert does the heavy lifting, not the side challenging the expert.
Not Every Court Uses the Daubert Standard
Daubert applies in all federal courts and roughly three dozen states that have adopted some version of it. Several major jurisdictions still follow the older Frye standard, which comes from a 1923 D.C. Circuit decision. Under Frye, expert testimony is admissible if the underlying methodology has “general acceptance” in the relevant scientific community. General acceptance is only one of the five Daubert factors, and Frye courts do not perform the broader reliability analysis.
States still following Frye include California, Illinois, Maryland, Minnesota, New Jersey, New York, Pennsylvania, and Washington. A handful of other states use hybrid approaches. If a case sits in state court, the standard depends entirely on where it was filed. Filing a “Daubert motion” in a Frye jurisdiction accomplishes nothing; the challenge has to be framed under the applicable state standard.
When Each Motion Is Filed
Neither motion has a single national deadline. In federal civil cases, the court’s scheduling order sets the deadline for pretrial motions.6Cornell Law School. Federal Rules of Civil Procedure Rule 16 – Pretrial Conferences, Scheduling, Management In federal criminal cases, the court may set a deadline at arraignment, and if no deadline is set the default cutoff is the start of trial.7Cornell Law School. Federal Rules of Criminal Procedure Rule 12 – Pleadings and Pretrial Motions
As a practical matter, Daubert challenges tend to be filed later than general motions in limine, because they depend on expert discovery. You can’t meaningfully challenge an expert’s methodology until you’ve reviewed the report and often taken the deposition. General motions in limine are frequently filed closer to trial, sometimes as part of a final pretrial conference.
What Happens When Each Motion Succeeds
A granted motion in limine means the excluded evidence cannot be mentioned in front of the jury. Attorneys cannot reference it during opening statements, direct or cross-examination, or closing arguments. Violating the ruling can trigger monetary sanctions, contempt findings, or a mistrial if the breach is severe enough to taint deliberations.
A granted Daubert motion can hit harder. When a court excludes a party’s only expert on a critical issue, the case often cannot survive. In many civil cases, expert testimony is the only way to prove elements like causation or damages. Losing the expert frequently leads to summary judgment against the party who needed the testimony, or forces a settlement on unfavorable terms. Judges sometimes limit the scope of an expert’s testimony rather than excluding the witness entirely.
Choosing the Right Motion
File a motion in limine when the concern is that otherwise relevant evidence would unfairly prejudice the jury: prior bad acts, inflammatory photographs, references to insurance coverage, settlement discussions. The evidence might carry some probative value, but the risk of emotional decision-making outweighs the informational payoff.
File a Daubert motion when the concern is the reliability of an expert’s methodology. The expert may have impressive credentials but used a flawed testing protocol, relied on insufficient data, or applied a technique the relevant professional community does not accept. Daubert challenges are especially common in toxic tort, medical malpractice, patent, and products liability cases where dueling experts are central to both sides’ theories.
In complex litigation, attorneys routinely file both. The motions address different vulnerabilities, and there is no rule against combining them. Match the tool to the problem: prejudice concerns go to the motion in limine, and reliability concerns go to the Daubert motion.