Checklist · Litigation

Challenging an Expert Under Daubert and Rule 702: A Practical Checklist

Type
Checklist
Jurisdiction
National
Date
2024-07-01
Topic
Litigation

A Daubert motion is not a jury argument made early — it is a threshold admissibility fight that the proponent of the expert must win by a preponderance of the evidence. This checklist walks the challenge in fourteen phases: mining the Rule 26(a)(2) report and the expert's file, breaking Rule 702 into its four independent requirements, attacking qualification, testing the methodology against the Daubert factors, adapting the analysis to experience-based experts after Kumho Tire, exposing the analytical gap between data and conclusion under Joiner, and using the 2023 amendment to Rule 702 — which restated the preponderance standard and added the requirement that the opinion reflect a reliable application of the methodology to the facts. It then covers Rule 703 and inadmissible bases, Rule 403 and the aura of expertise, the Daubert deposition, drafting the motion and requesting a hearing, partial exclusion as the realistic win, defending your own expert against the same attacks, and preserving the issue for an appeal you will argue under abuse-of-discretion review. A running worked example follows a reasonable-royalty damages opinion built on an assumption nobody ever verified.

Challenging an Expert Under Daubert and Rule 702: A Practical Checklist

Litigation > Evidence | Published 1 July 2024 - Updated 24 November 2025 | UpLaw - uplaw.us

An expert opinion is only as good as the weakest link between the data and the conclusion. Daubert practice is the disciplined search for that link — and the 2023 amendment to Rule 702 put the burden of defending it squarely on the party who offered the expert.

Keywords: Daubert motion, Rule 702, expert testimony, gatekeeping, Kumho Tire, Joiner, analytical gap, ipse dixit, 2023 amendment, Rule 26(a)(2) report, Daubert deposition, Rule 703, Rule 403, reliable application, abuse of discretion

How to use this checklist

Most lawyers approach a Daubert motion the way they approach a closing argument: they list everything wrong with the other side's expert and hope the judge is persuaded. That is the wrong instrument. Federal Rule of Evidence 702 is an admissibility rule, decided by the judge under Federal Rule of Evidence 104(a), on which the proponent bears the burden of proof by a preponderance of the evidence. Your job is not to show the expert is wrong. Your job is to show the proponent cannot carry that burden on one of the four things Rule 702 requires.

Scope note. This checklist is about the federal standard: Rule 702 as amended effective 1 December 2023, and the Daubert line of Supreme Court cases. Expert admissibility in state court is a matter of state law, and it is not uniform. Most states have adopted Daubert or an evidence rule modeled on Rule 702, but a meaningful minority — New York and Illinois among them — continue to apply Frye's "general acceptance" test or a state-specific variant, and even the Daubert states have not all adopted the 2023 amendment's express preponderance language. Confirm your forum's standard before importing any of this into a state-court motion.

The running example throughout: Beacon Ridge Instruments sues Solstice Cartridge Co. for patent infringement. Beacon Ridge's damages expert, Dr. Miriam Calloway, opines that a hypothetical negotiation would have produced a 7% running royalty on Solstice's entire cartridge revenue — $41 million. Her model rests on an assumption that the patented filter membrane "drives approximately 60% of customer purchasing decisions." Nobody ever tested that assumption. That single sentence is the case.

Phase 1 — Mine the Rule 26(a)(2) report and the expert's file

  • [ ] Confirm whether the expert is a retained/specially-employed expert owing a written report under Fed. R. Civ. P. 26(a)(2)(B), or a non-retained expert (treating physician, employee) subject only to the lighter 26(a)(2)(C) disclosure.
  • [ ] Check the report against every mandatory element of Rule 26(a)(2)(B): complete statement of all opinions and the basis and reasons for them; the facts or data considered; exhibits; qualifications and 10-year publication list; a 4-year testimony list; and compensation.
  • [ ] Diary the disclosure deadlines under Fed. R. Civ. P. 26(a)(2)(D) — absent a scheduling order, 90 days before trial, and 30 days after for rebuttal — and confirm the scheduling order's actual dates.
  • [ ] Serve document requests and a subpoena (if needed) for the expert's file: data sets, code, models, spreadsheets with live formulas, literature relied on, and prior reports and transcripts.
  • [ ] Understand the shields: draft reports and most attorney–expert communications are protected under Fed. R. Civ. P. 26(b)(4)(B)–(C), but the exceptions are wide open — compensation, facts or data provided by counsel that the expert considered, and assumptions provided by counsel that the expert relied on.
  • [ ] Pull the expert's prior testimony, prior published methodology, and any prior exclusion orders. Inconsistency between the current opinion and a prior sworn methodology is the single most productive vein in Daubert practice.
  • [ ] Ask whether a Rule 37(c)(1) preclusion motion is the cheaper path: an opinion never disclosed, or disclosed after the deadline, may be excluded without any Rule 702 analysis at all unless the failure was substantially justified or harmless.

Why it matters, and the traps. Every successful Daubert motion is built out of the opponent's own paper. The report is a sworn commitment to a methodology, and Rule 26(a)(2)(B) forces the expert to state the basis and reasons — which is exactly where the unsupported assumption lives. The trap is treating the report as the whole record: the model in the spreadsheet, not the prose in the report, is where the assumption was actually implemented, and experts routinely hard-code inputs they never mention. In our example, Dr. Calloway's report says the 60% figure comes from "industry experience and discussions with plaintiff's engineers." The native spreadsheet shows the cell is a typed constant with no source and no sensitivity analysis. That is the motion. For the underlying discovery mechanics, see Federal Civil Discovery: Mastering the Tools, Rules, and Pitfalls, Rule 26 Initial Disclosures and the Discovery Plan: A Practical Checklist, and Rule 37(c)(1) and the Preclusion of Undisclosed Evidence: A Practical Guide. If the expert's file or native model is withheld, the path runs through Moving to Compel Discovery and Seeking Rule 37 Sanctions: A Practical Checklist — and it is worth the fight, because the spreadsheet is usually where the motion is hiding.

Phase 2 — Frame the four Rule 702 requirements as four separate attacks

  • [ ] Write out Rule 702 as amended in 2023 and break it into its elements. The proponent must show, 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 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.
    • [ ] Plus the threshold: the witness must be qualified by knowledge, skill, experience, training, or education.
  • [ ] Assign every criticism you have to exactly one of those five buckets. Criticisms that fit none of them are jury arguments — save them for cross.
  • [ ] Draft one heading per surviving bucket. A motion organized around Rule 702's text reads as an admissibility argument; a motion organized around "seven problems with Dr. Calloway" reads as advocacy the court can defer to the jury.

Why it matters, and the traps. Courts deny Daubert motions that ask them to weigh evidence. They grant motions that identify a gap the proponent cannot fill. The discipline of the five buckets forces you to test each criticism against the question a judge actually asks: is this a reason to keep it out, or a reason for the jury to discount it? The trap is the "shotgun" motion, which buries a real 702(b) failure among six weight arguments and invites the standard "goes to weight, not admissibility" denial. In Beacon Ridge, the 60% assumption is a 702(b) and 702(d) failure — insufficient facts and unreliable application. Dr. Calloway's credentials are excellent; do not spend a page on them.

Phase 3 — Attack qualification: the right expertise for THIS opinion

  • [ ] Compare the expert's actual training and experience to the specific opinion offered, not to the field in general.
  • [ ] Identify opinions that stray outside the discipline: an economist opining on consumer psychology; a mechanical engineer opining on human factors; an accountant opining on technical apportionment.
  • [ ] Look for the "borrowed expertise" move — the expert who adopts another discipline's conclusion wholesale without the ability to evaluate it.
  • [ ] If qualification is marginal, ask for partial exclusion of the out-of-lane opinions rather than disqualification of the witness.

Why it matters, and the traps. Qualification is the weakest of the five attacks, because Rule 702 qualifies experts by "knowledge, skill, experience, training, or education" — any one suffices, and courts are generous. The productive version is narrow: Dr. Calloway is a qualified economist, but her 60% "purchasing driver" figure is a consumer-preference claim that ordinarily requires a conjoint or survey methodology she has never performed. She is not qualified to generate that input; she is at most qualified to use one supplied by a qualified expert. Since none was, the input has no source. That is a qualification argument that lands because it converts into a reliability argument.

Phase 4 — Attack reliability: the Daubert factors

  • [ ] Run the Daubert factors from Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993), remembering they are flexible and non-exclusive:
    • [ ] Can the theory or technique be (and has it been) tested?
    • [ ] Has it been subjected to peer review and publication?
    • [ ] Is there a known or potential rate of error?
    • [ ] Are there standards controlling the technique's operation, and were they followed?
    • [ ] Is the method generally accepted in the relevant community?
  • [ ] Add the field-specific factors courts actually use: whether the opinion grew out of independent research or was developed for litigation; whether the expert accounted for obvious alternative explanations; whether the expert used the same intellectual rigor in court as in professional work.
  • [ ] Test whether the expert followed the standards of their own discipline — the most damaging showing is not that the method is bad, but that the expert departed from it.
  • [ ] Check whether the method is validated for the use made of it here (a screening tool used as a diagnostic; a marketing survey used to prove causation).

Why it matters, and the traps. Daubert replaced the Frye "general acceptance" test (Frye v. United States, 293 F. 1013 (D.C. Cir. 1923)) with a flexible reliability inquiry, and general acceptance survives only as one factor among several. The trap is treating the five factors as a scorecard: a court is not required to run them at all, and reciting them mechanically for a damages expert is a tell that you have not thought about the field. Ask instead what this discipline treats as rigor. For reasonable-royalty testimony, that means the Georgia-Pacific framework (Georgia-Pacific Corp. v. U.S. Plywood Corp., 318 F. Supp. 1116 (S.D.N.Y. 1970)), apportionment to the patented feature, and comparable licenses that are actually comparable — with the Federal Circuit having rejected arbitrary rules of thumb (Uniloc USA, Inc. v. Microsoft Corp., 632 F.3d 1292 (Fed. Cir. 2011)) and having sharply limited use of the entire market value of a multi-component product (LaserDynamics, Inc. v. Quanta Computer, Inc., 694 F.3d 51 (Fed. Cir. 2012)). Dr. Calloway applied the 7% rate to Solstice's entire cartridge revenue on the strength of the unverified 60% figure. That is a standards-and-application failure in her own field, which is worth more than any abstract discussion of error rates. On the survey-methodology analogue, see Daubert and the Consumer Survey: A Practical Guide to Excluding Expert Testimony in Trademark Cases and Reading and Building Trademark Confusion Surveys: A Practical Guide to Expert Methodology.

Phase 5 — Non-scientific and experience-based experts after Kumho Tire

  • [ ] Confirm that the gatekeeping obligation applies: Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999), holds that Rule 702 governs all expert testimony — "scientific," "technical," and "other specialized knowledge" alike.
  • [ ] Recognize the court's latitude: Kumho Tire also holds that the trial court has broad discretion in deciding how to assess reliability, and the Daubert factors may not apply at all.
  • [ ] For an experience-based expert, force the proponent to answer the Advisory Committee's three questions: how does the experience lead to the conclusion, why is that experience a sufficient basis, and how is the experience reliably applied to the facts?
  • [ ] Demand a testable articulation. "In my 30 years I have seen this pattern" is a credential, not a method.
  • [ ] Watch for the "experience laundering" move — an expert who cannot describe a methodology, then relabels the conclusion as a judgment call.

Why it matters, and the traps. Kumho Tire is a double-edged authority. It closed the escape hatch that would have exempted non-scientific experts from scrutiny, but it also gave district courts room to apply a lighter touch. The trap is arguing that an experience-based expert must satisfy the Daubert five — that argument loses, and it costs you credibility. Argue instead that experience-based testimony still requires a method the expert can articulate and the court can evaluate. Dr. Calloway's "industry experience" is precisely the claim Kumho Tire permits a court to probe: what experience, with what products, generating what data, and how does it get you to 60% rather than 20%?

Phase 6 — The analytical gap: Joiner and "ipse dixit"

  • [ ] Trace the opinion backwards, one step at a time, from the conclusion to the data. Write each inferential step on its own line.
  • [ ] Find the step that is asserted rather than supported. That is the gap.
  • [ ] Frame it in Joiner's language: General Electric Co. v. Joiner, 522 U.S. 136 (1997), holds that "nothing in either Daubert or the Federal Rules of Evidence requires a district court to admit opinion evidence that is connected to existing data only by the ipse dixit of the expert," and that a court "may conclude that there is simply too great an analytical gap between the data and the opinion proffered."
  • [ ] Distinguish the two flavors of gap: (i) the data do not support the inference (extrapolation from animal studies, from a different product, from a non-comparable license); and (ii) there are no data at all behind a load-bearing input.
  • [ ] Quantify the stakes: show the court what happens to the conclusion if the assumption changes. A number that swings from $41 million to $6 million on an input nobody tested is a gap, not a quibble.

Why it matters, and the traps. Joiner is the most useful case in the arsenal because it authorizes the court to look at conclusions, not just methods — the "methodology/conclusion" distinction is not so neat that a court must admit an opinion whose method is conventional but whose application is unsupported. The trap is failing to localize the gap. A motion that says "the whole opinion is unreliable" invites a denial; a motion that says "cell D14 of Exhibit 7 is a typed constant with no source, and the entire damages number is a linear function of it" is nearly self-executing. Run the sensitivity analysis the expert should have run and put it in your brief as a table.

Phase 7 — What the 2023 amendment to Rule 702 changed

  • [ ] Quote the amended rule. Effective December 1, 2023, Rule 702 provides that a qualified expert may testify "if the proponent demonstrates to the court that it is more likely than not that" the four requirements are met.
  • [ ] Cite the Advisory Committee's stated reason: many courts had incorrectly held that the reliability requirements were questions of weight for the jury rather than admissibility, and had failed to apply the Rule 104(a) preponderance standard. The amendment does not change the substantive standard; it corrects that error. (The preponderance standard for Rule 104(a) preliminary questions was already settled — see Bourjaily v. United States, 483 U.S. 171 (1987).)
  • [ ] Use the amended subsection (d): the opinion must reflect a reliable application of the principles and methods to the facts. A sound method, sloppily or selectively applied, now has an express textual hook.
  • [ ] Cite the amendment against the reflexive "goes to weight" response. That phrase, standing alone, is now an incomplete answer.
  • [ ] Note the Advisory Committee's related caution about overstatement: experts must not express degrees of confidence unsupported by their methodology (a point sharpened by the forensic-discipline debates, but general in application).

Why it matters, and the traps. The 2023 amendment is the most important development in expert practice in twenty years, and it is chronically under-briefed. Pre-2023 opinions in your circuit reciting that "vigorous cross-examination" cures reliability defects should be met head-on with the Advisory Committee's note. The trap is overclaiming: the amendment did not raise the bar, and courts have said so. Argue it as a correction of a misapplication, not a new regime. In Beacon Ridge, the amendment is worth a full section: Beacon Ridge, not Solstice, must show it is more likely than not that a 60% figure with no source is a reliable application of Georgia-Pacific apportionment. It cannot.

Phase 8 — Attack fit and relevance

  • [ ] Ask Daubert's "fit" question: does the opinion, even if reliable in the abstract, help the trier of fact decide a fact in this case?
  • [ ] Identify opinions keyed to the wrong legal standard (a negligence-flavored opinion in a strict-liability case; a "likelihood of confusion" opinion measuring the wrong population).
  • [ ] Identify opinions that measure the wrong thing (survey of the wrong universe; damages model built on the wrong date, wrong geography, or wrong accused product).
  • [ ] Strike opinions that are pure legal conclusions — an expert may embrace an ultimate issue under Fed. R. Evid. 704(a), but may not instruct the jury on the law or opine that conduct was "unlawful" or "breached the contract."
  • [ ] Strike opinions that merely narrate the documents or recite party positions — that is argument, not specialized knowledge, and it does not help the jury.
  • [ ] In a criminal case, check Fed. R. Evid. 704(b): no opinion on whether the defendant did or did not have the requisite mental state.

Why it matters, and the traps. Fit is the quiet killer. An impeccably reliable study of the wrong population proves nothing about your case, and "helpfulness" is a low bar only when the opinion is about the disputed fact. The trap is missing the fit problem because the methodology looks impressive. If Dr. Calloway's comparable licenses are all bare patent licenses and the hypothetical negotiation here would have involved a bundled supply agreement, the licenses do not fit — no matter how carefully she analyzed them.

Phase 9 — Rule 703 and inadmissible bases; Rule 403 and the aura of expertise

  • [ ] Test the basis under Fed. R. Evid. 703: an expert may rely on inadmissible facts or data only if experts in the field would reasonably rely on that kind of information.
  • [ ] Where the basis is inadmissible, invoke Rule 703's reverse-403 disclosure limit: the proponent may disclose the inadmissible basis to the jury only if its probative value in helping the jury evaluate the opinion substantially outweighs its prejudicial effect. This is a deliberately proponent-hostile balance.
  • [ ] Watch for the conduit problem — the expert who launders otherwise-inadmissible hearsay (a party's self-serving internal memo, an anonymous complaint log) into evidence by "relying" on it.
  • [ ] Use Fed. R. Evid. 705 on cross: the expert may be required to disclose the underlying facts or data.
  • [ ] Preserve a Fed. R. Evid. 403 objection: expert testimony carries an aura of reliability, and cumulative, confusing, or minimally probative expert opinion can be excluded even if it clears Rule 702.
  • [ ] Consider Fed. R. Evid. 706 (court-appointed expert) in a genuine battle-of-experts case — rare, but occasionally the right ask.

Why it matters, and the traps. Rule 703 is the forgotten rule. It does two things: it authorizes reliance on inadmissible material, and it restricts the presentation of that material to the jury. Practitioners remember the first half and forget the second. The trap on the 403 side is over-reliance: a court will rarely exclude a Rule 702-compliant expert under 403 alone, but 403 is excellent for trimming — the demonstratives, the inflammatory language, the third cumulative expert on the same point. For the balancing framework, see Rule 403 and Unfair Prejudice: A Practical Guide to the Balancing Test and, for the surrounding rules architecture, The Federal Rules of Evidence: A Comprehensive Guide, Hearsay and Its Exceptions: A Comprehensive Guide, and The Federal Evidence Toolkit. On getting the expert's underlying exhibits and models into evidence in the first place, see Laying Foundations and Admitting Exhibits: A Practical Checklist.

Phase 10 — The Daubert deposition: locking in the methodology and the concessions

  • [ ] Set the goal: you are not there to argue. You are there to (i) close the universe, (ii) lock the methodology, and (iii) harvest concessions you can quote in the brief.
  • [ ] Close the universe: "Are these all your opinions?" "Is everything you relied on listed in Exhibit A?" "Is there any analysis you did that is not in the report?" "Do you intend to do any further work?"
  • [ ] Lock the method: have the expert state the methodology's name, its source, its standard steps, and the authority that describes it. Then walk each step and confirm whether it was performed.
  • [ ] Harvest the concessions, in order:
    • [ ] The assumption is an assumption ("You did not independently verify the 60% figure, correct?").
    • [ ] It came from counsel or the client ("Who gave you that number?").
    • [ ] It is load-bearing ("If the figure were 20%, your royalty base changes, correct?").
    • [ ] There is an accepted way to test it that you did not use ("A conjoint analysis or a consumer survey could measure purchase drivers, correct? You did not perform one?").
    • [ ] Your discipline expects the test ("Would an economist performing an apportionment analysis in a non-litigation engagement typically want an empirical basis for a driver figure?").
  • [ ] Do not argue the ultimate point. Do not ask "so your opinion is unreliable, isn't it?" You will get a speech, and the speech will go in their opposition brief.
  • [ ] Ask the sensitivity question and stop.
  • [ ] Get the fee number and the percentage of the expert's income derived from litigation work — for cross, not for the motion.

Why it matters, and the traps. The Daubert deposition is a record-building exercise with a written product in mind. Every question should be one whose answer you would be willing to block-quote. The classic trap is the one-question-too-many: you have the concession that the 60% figure was never verified, and then you ask why, and Dr. Calloway explains for four transcript pages how three engineers, a customer-win/loss database, and a decade of market experience all converge on 60%. You have just written her opposition. Take the concession and move on. For technique, see Preparing to Take a Deposition: A Practical Checklist, Taking Depositions in Federal Civil Litigation: A Comprehensive Guide, and The Federal Deposition Toolkit: From Notice to Trial Testimony.

Phase 11 — Drafting the motion; requesting a hearing; timing

  • [ ] Find your deadline. Daubert motions are usually due under the scheduling order (Fed. R. Civ. P. 16(b)) — often with dispositive motions, sometimes with motions in limine, sometimes on a separate track. Check the judge's standing order; many cap the number of Daubert motions or require a pre-motion letter.
  • [ ] Decide whether to file with summary judgment. If the expert's opinion is the only evidence of an essential element, exclusion plus Rule 56 is a case-dispositive one-two.
  • [ ] Structure the brief around Rule 702's elements, one heading each, most-fatal first.
  • [ ] Lead with the gap, not the credentials. Attach: the report, the relevant transcript excerpts (short, block-quoted), the native model, and your sensitivity table.
  • [ ] State the standard clearly: Rule 104(a); proponent's burden; preponderance; cite the 2023 amendment and its Advisory Committee note.
  • [ ] Ask for the relief you actually want, in the alternative: exclusion of the opinion; exclusion of specified opinions; or exclusion of the opinion unless the expert can identify record support for the assumption.
  • [ ] Request a hearing if — and only if — live testimony helps you. A hearing gives the proponent a chance to rehabilitate and, in some courts, to shore up a deficient record. If the transcript concessions are clean, a paper record may be better.
  • [ ] Never treat a hearing as automatic. A court is not required to hold one, and refusing one is reviewed only for abuse of discretion.

Why it matters, and the traps. The single most common tactical error is requesting a hearing reflexively. A Daubert hearing is an opportunity — for whoever is better prepared. If the record already shows Dr. Calloway conceding that she never verified the load-bearing input, a hearing invites her to explain it away with material never disclosed in the report. The second most common error is filing a Daubert motion and a summary judgment motion that do not talk to each other; if exclusion leaves the plaintiff with no damages evidence, say so, in the Rule 56 brief, in one sentence, with a cross-reference. See Moving for Summary Judgment Under Rule 56: A Practical Checklist and, for how the Daubert motion sits within the broader pretrial sequence, The Civil Pretrial Toolkit: From Pleadings to Summary Judgment and Federal Civil Litigation: A Roadmap and Resource Guide.

Phase 12 — Partial exclusion, limiting instructions, and the practical win

  • [ ] Identify the severable opinions. Courts far more often trim than exclude.
  • [ ] Ask the court to strike specific paragraphs of the report and to bar specific testimony at trial.
  • [ ] Seek an order barring the expert from using the excluded assumption as a predicate for surviving opinions.
  • [ ] Seek a limiting instruction and a ruling on demonstratives.
  • [ ] Convert the ruling into a motion in limine and get it into the final pretrial order so it is enforceable at trial.
  • [ ] Recalculate the case's settlement value the day the order issues. A damages expert reduced from $41 million to a per-unit apportioned figure has changed the negotiation more than most trial verdicts do.

Why it matters, and the traps. Total exclusion is rare; partial exclusion is common and often decisive. The trap is winning on paper and losing at trial because the order was never operationalized — the expert testifies "in my experience the membrane is what customers buy," and by the time you object the jury has heard it. Get the order stated in terms of what the witness may not say, and put it in the pretrial order. See Preparing for Trial: A Pretrial Order and Trial Readiness Checklist and Federal Civil Trial Practice: From Final Pretrial Conference to Verdict.

Phase 13 — Defending your own expert against the same attacks

  • [ ] Build the report as if it will be exhibit A to a Daubert motion. State the methodology by name, cite its authority, and show every step.
  • [ ] Source every input. If an assumption comes from counsel, say so, say why it is reasonable, and cite the record evidence supporting it — Rule 702(b) requires sufficient facts or data, and assumptions grounded in record evidence are permissible.
  • [ ] Run and disclose a sensitivity analysis. An expert who shows the conclusion's response to input variation looks rigorous; one who hides it looks exposed.
  • [ ] Address the obvious alternative explanation in the report itself. Silence reads as failure to consider.
  • [ ] Prepare the expert for the concession sequence in Phase 10 — especially the "you didn't verify it" question. The right answer identifies the record support, not a speech about experience.
  • [ ] Do not overstate. Calibrate the confidence language to what the method supports.
  • [ ] Consider a supplemental or rebuttal report where the rules and scheduling order permit — but understand that untimely "supplementation" that fixes a hole is a Rule 37(c)(1) problem.

Why it matters, and the traps. The best Daubert defense is written six months before the motion. Every trap in Phases 1–9 is a drafting instruction in reverse. The trap on this side is the expert who is "too helpful" — who accepts counsel's assumptions without asking for their basis and then cannot defend them. The remedy is uncomfortable and cheap: ask your own expert, before the report is final, "if the other side moves to exclude you, what is the weakest sentence in this document?" Then fix that sentence. For damages models specifically, see The Litigation Damages Toolkit: Valuing and Proving Money Awards; for surveys, Designing a Defensible Confusion Survey: A Practical Checklist; and for protecting your expert in the chair, Defending Depositions in Federal Court: A Comprehensive Guide and The Federal Discovery Toolkit: A Roadmap From Rule 26(f) to Sanctions.

Phase 14 — Preserving the issue for appeal

  • [ ] Object with specificity and on the record. Fed. R. Evid. 103(a) requires a timely objection stating the specific ground; a general "objection, foundation" will not preserve a Rule 702(d) argument.
  • [ ] Know the safe harbor: under Fed. R. Evid. 103(b), once the court rules definitively on the record — before or at trial — you need not renew the objection to preserve it. If the ruling was conditional or deferred, you must renew.
  • [ ] Make an offer of proof (Rule 103(a)(2)) if your expert was excluded and the substance is not apparent from the record.
  • [ ] Understand the standard you face: General Electric Co. v. Joiner, 522 U.S. 136 (1997), holds that a court's decision to admit or exclude expert testimony is reviewed for abuse of discretion — and Kumho Tire extends that deference to the court's choice of how to test reliability.
  • [ ] Understand the stakes on the other side: Weisgram v. Marley Co., 528 U.S. 440 (2000), holds that a court of appeals that finds expert testimony erroneously admitted may direct entry of judgment as a matter of law for the verdict loser rather than remand for a new trial. A proponent who wins on a shaky expert has not necessarily won.
  • [ ] Move under Rule 50 at the close of evidence and renew post-trial, tying the motion to the excluded or improperly admitted expert.

Why it matters, and the traps. Abuse-of-discretion review is why the Daubert fight is a district court fight. You will not win it on appeal by re-arguing reliability. What you can win on appeal is a court that applied the wrong legal standard — that put the burden on the challenger, that treated reliability as a jury question, that never performed a gatekeeping analysis at all. That is a legal error, and after the 2023 amendment it is a well-marked one. The trap is a silent record: if the court denies your motion in a one-line docket order and you never renew at trial, you may have preserved nothing. See Taking a Civil Appeal: A Practical Checklist and Federal Civil Appeals: A Comprehensive Guide.

The worked example, start to finish: Beacon Ridge Instruments v. Solstice Cartridge Co.

The phases above are the method. Here is what the method produces in a single case, so you can see how a scattered pile of complaints becomes a two-page argument the court can actually grant.

The opinion under attack. Dr. Miriam Calloway, Beacon Ridge's damages expert, offers a reasonable-royalty opinion: a hypothetical negotiation on the eve of first infringement would have yielded a 7% running royalty applied to all of Solstice's cartridge revenue over the damages period — $41.2 million. The royalty base is the full cartridge. The justification for using the full cartridge, rather than the patented filter membrane inside it, is one sentence in the report: the membrane "drives approximately 60% of customer purchasing decisions."

What the file showed (Phase 1). The Rule 26(a)(2)(B) report recites that the 60% figure rests on "industry experience and discussions with plaintiff's engineers." The native spreadsheet produced from the expert's file tells a different story. Cell D14 of the damages model is the string 0.60, typed. It feeds the royalty-base calculation directly and linearly. There is no source cell, no citation, no range, and no sensitivity tab. No conjoint study, no survey, no customer win/loss data, and no document produced in discovery uses the number 60%.

Sorting the criticisms (Phase 2). Solstice's team generated eleven complaints about the opinion. Sorted into the Rule 702 buckets, they came out like this:

Complaint Bucket Keep?
The 60% driver figure has no empirical source 702(b) — insufficient facts or data Yes — lead with it
Applying the 7% rate to the entire cartridge is unapportioned 702(d) — unreliable application of Georgia-Pacific Yes
Dr. Calloway has never performed a conjoint or survey study Qualification (narrow) → feeds reliability Yes, as support
Two of the five "comparable" licenses are bundled supply agreements 702(d) / fit Yes
Her rate is at the top of the range in her own comparables Weight No — cross-examination
She is paid $900/hour and earns 80% of her income from testifying Weight / bias No — cross-examination
She did not read the inventor's deposition Weight No — cross-examination

Seven complaints in; four survive as admissibility arguments. The other three are cross-examination, and putting them in the brief would have diluted it. This sorting step is the single highest-leverage thirty minutes in the entire exercise.

The deposition (Phase 10). Four concessions, in sequence, each one question long, and then silence:

  • "You did not independently verify that the membrane drives 60% of purchasing decisions, correct?" — Correct.
  • "The 60% figure was provided to you in a conversation with plaintiff's engineering team?" — That's right.
  • "Conjoint analysis and consumer surveys are accepted methods for measuring purchase drivers?" — They are.
  • "You did not perform either one in this case?" — I did not.

Counsel then asked the sensitivity question — "If the driver figure were 20% rather than 60%, the royalty base would be smaller, correct?" — got a yes, and stopped. He did not ask why she hadn't run a survey. That question would have handed her four transcript pages in which to explain how her experience, three engineers, and a decade in the industry all converge on 60%. Take the concession; sit down.

The sensitivity table (Phase 6). The brief did the analysis the expert should have done, and put it on page 2:

Assumed driver share Apportioned royalty base Damages at 7%
60% (Dr. Calloway's typed constant) Full cartridge revenue $41.2M
40% Apportioned $27.5M
20% Apportioned $13.7M
8% (Solstice's expert, from a conjoint study) Apportioned $5.5M

That table is the motion. It shows the court, without argument, that the entire damages case is a linear function of a number nobody ever tested — the Joiner analytical gap in a single visual.

The motion and the relief (Phase 11–12). Solstice moved to exclude Dr. Calloway's royalty-base opinion, in the alternative asking that she be barred from applying the 7% rate to any base broader than the apportioned value of the membrane, and barred from telling the jury that the membrane drives customer demand. It requested no hearing — the transcript concessions were clean, and a hearing would only have let Beacon Ridge build the record it had failed to build in the report.

The ruling. The court did what courts usually do: it trimmed. It found Dr. Calloway qualified and her Georgia-Pacific framework reliable in the abstract, but held that Beacon Ridge had not shown by a preponderance under amended Rule 702(d) that the unsourced 60% input reflected a reliable application of that framework. It struck the entire-market-value royalty base, barred the demand-driver testimony, and permitted her to opine on rate only. Beacon Ridge's damages case went from $41.2 million to a number in the single-digit millions, and the case settled within a month.

That is the realistic shape of a Daubert win: not a witness destroyed, but a number cut by 85% and a settlement posture inverted. For the surrounding patent-damages doctrine, see What an IP Case Is Worth: A Guide to Intellectual Property Damages and The Patent Infringement Lawsuit From Filing to Appeal: A Comprehensive Guide; for the claim-construction fight that usually precedes it, Claim Construction and the Markman Hearing: A Practical Checklist.

Common mistakes to avoid

  1. Filing a jury argument as a Daubert motion. If your best point is that the expert is biased, overpaid, or wrong, that is cross-examination. Rule 702 is about the reliability of the method and its application, not the persuasiveness of the conclusion.
  2. Attacking the credentials of a well-credentialed expert. It wastes pages and signals you have nothing better.
  3. Missing the native file. The report is prose; the model is evidence. Get the spreadsheet with live formulas.
  4. Reciting the five Daubert factors at a non-scientific expert. Kumho Tire says they may not apply. Argue the discipline's own standards instead.
  5. Failing to localize the gap. "The whole opinion is unreliable" loses. "Cell D14 is unsourced and the number is linear in it" wins.
  6. Ignoring the 2023 amendment. It is the answer to "goes to weight, not admissibility." Brief it, with the Advisory Committee note.
  7. Requesting a hearing reflexively. A hearing is a rehabilitation opportunity for the other side.
  8. Asking one question too many at the Daubert deposition. Take the concession. Sit down.
  9. Winning the motion and losing the trial because the order was never converted into an enforceable in limine ruling in the pretrial order.
  10. Forgetting Rule 703's disclosure limit. Even where reliance on inadmissible material is proper, disclosing it to the jury requires the probative value to substantially outweigh the prejudice.
  11. Preserving nothing. A general objection to a Rule 702(d) problem preserves a Rule 702(d) problem badly, or not at all.
  12. Treating exclusion as the only win. Trimming a $41 million opinion to $6 million is a win, and it happens more often than exclusion does.

The consolidated Daubert checklist

  • [ ] Rule 26(a)(2) report obtained and audited against every required element
  • [ ] Expert's full file, native models, and data produced
  • [ ] Prior reports, transcripts, and exclusion orders pulled
  • [ ] Rule 37(c)(1) preclusion evaluated as an alternative path
  • [ ] Every criticism sorted into: qualification / 702(a) help / 702(b) facts and data / 702(c) reliable method / 702(d) reliable application
  • [ ] Qualification tested against the specific opinion, not the field
  • [ ] Daubert factors run — and, where the expert is experience-based, replaced with the discipline's own standards under Kumho Tire
  • [ ] Analytical gap localized to a specific, load-bearing, unsupported step (Joiner)
  • [ ] Sensitivity analysis run and tabled
  • [ ] 2023 amendment briefed: preponderance burden on the proponent; reliable application under 702(d)
  • [ ] Fit and helpfulness tested; legal conclusions and document narration flagged
  • [ ] Rule 703 basis and disclosure limit evaluated; Rule 403 objection preserved
  • [ ] Daubert deposition taken; concessions harvested; universe closed
  • [ ] Scheduling-order deadline calendared; judge's standing order checked
  • [ ] Motion drafted around Rule 702's elements; alternative relief requested
  • [ ] Hearing requested only if live testimony helps
  • [ ] Coordination with Rule 56 motion confirmed
  • [ ] Partial-exclusion relief specified in terms of what the witness may not say
  • [ ] Ruling carried into the final pretrial order and motions in limine
  • [ ] Objection made with specificity; definitive ruling confirmed under Rule 103(b); offer of proof made if needed
  • [ ] Rule 50 motion made and renewed
  • [ ] Own expert audited against every one of the above

Primary Authority

Rules of Evidence

  • Fed. R. Evid. 702 (Testimony by Expert Witnesses; as amended effective 1 December 2023, adding the express "more likely than not" proponent burden and the requirement in subsection (d) that the opinion reflect a reliable application of the principles and methods to the facts of the case), and the Advisory Committee Note to the 2023 amendment
  • Fed. R. Evid. 703 (Bases of an Expert's Opinion Testimony; reverse-403 limit on disclosing inadmissible bases to the jury)
  • Fed. R. Evid. 704 (Opinion on an Ultimate Issue; 704(b) mental-state limit in criminal cases)
  • Fed. R. Evid. 705 (Disclosing the Facts or Data Underlying an Expert's Opinion)
  • Fed. R. Evid. 706 (Court-Appointed Expert Witnesses)
  • Fed. R. Evid. 104(a) (preliminary questions; court not bound by the evidence rules)
  • Fed. R. Evid. 403 (excluding relevant evidence for prejudice, confusion, or waste of time)
  • Fed. R. Evid. 103 (preserving a claim of error; definitive rulings; offers of proof)

Rules of Civil Procedure

Cases

Note: many state courts continue to apply Frye or a state-law variant rather than Daubert*. Confirm the governing standard in your forum before importing federal doctrine into a state-court motion.*

Secondary Sources

  • Reference Manual on Scientific Evidence (Federal Judicial Center & National Research Council, 3d ed. 2011) — the standard judicial reference; the damages, statistics, and survey chapters are the ones to know
  • Wright & Miller, Federal Practice and Procedure (expert disclosure and Rule 702 practice)
  • Weinstein's Federal Evidence; Mueller & Kirkpatrick, Federal Evidence

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This checklist is general legal information from UpLaw (uplaw.us), not legal advice, and does not create an attorney-client relationship. Laws vary by state and change over time; verify current requirements and consult qualified counsel before acting.