Summary. Expert practice fails in two places: the disclosure, which is mechanical and unforgiving, and the reliability challenge, which the December 2023 amendment to Rule 702 made materially easier to win. This checklist covers both — selecting an expert whose qualifications match the specific opinion, preparing the report, taking and defending the deposition, and briefing or opposing exclusion. It incorporates the amended rule's two changes: the proponent must demonstrate admissibility by a preponderance, and the opinion must reflect a reliable application of the methodology. Each phase is paired with the reason it matters and the governing rule or case.

What this checklist is for. Getting your expert admitted and keeping the other side's out. For the doctrine, see Expert Witnesses After the 2023 Amendment to Rule 702.

Phase 1 — Selection

  • Match qualifications to the specific opinion, not the general field. A cardiologist is not automatically qualified on device firmware failure modes.
  • Read the expert's last five transcripts and every exclusion order entered against them.
  • Search their publications for positions inconsistent with the opinion you need.
  • Confirm availability through trial and willingness to be deposed.
  • Assess communication skill — a brilliant expert who cannot explain the method is a liability.
  • Consider a consulting (non-testifying) expert first to explore theories under the near-absolute protection of Rule 26(b)(4)(D).
  • Confirm no conflicts: prior engagement by the opposing party, access to their confidential information, or a prosecution bar issue.

Why this matters. Selection is the only stage where you have complete control. An expert with an exclusion history will face it in every subsequent case, and a mismatch between credentials and opinion is the easiest qualification challenge to make.

Phase 2 — The retained expert report, Rule 26(a)(2)(B)

  • A complete statement of all opinions and the basis and reasons for them. Opinions not in the report are generally inadmissible.
  • The facts or data considered — including material reviewed and rejected.
  • Exhibits that will be used to summarize or support the opinions.
  • Qualifications, including all publications in the previous 10 years.
  • All other cases in which the witness testified as an expert at trial or by deposition in the previous 4 years.
  • A statement of compensation for the study and testimony.
  • The expert writes the report; counsel may consult, but an expert who did not author their own analysis collapses on cross.
  • Assumptions provided by counsel and relied upon are identified — they are discoverable under Rule 26(b)(4)(C)(iii) regardless.
  • Verify the expert actually reviewed everything the report says they reviewed.

Why this matters. "Complete statement" is enforced. The most common late-case disaster is an expert offering an opinion at trial that was not in the report, which draws exclusion under Rule 37(c)(1) without any need for a Rule 702 motion.

Phase 3 — Non-retained experts, Rule 26(a)(2)(C)

  • Identify witnesses who will offer Rule 702, 703, or 705 opinions but were not retained: treating physicians, employees with specialized knowledge, government investigators.
  • Provide the subject matter on which they will present evidence.
  • Provide a summary of the facts and opinions expected.
  • Assess honestly whether the witness has crossed into (B) territory — an employee whose duties "regularly involve giving expert testimony," or a physician forming causation opinions after being retained rather than during treatment.

Why this matters. The (B)/(C) line is heavily litigated, and misclassifying a witness produces exclusion of the very testimony you needed. When in doubt, serve a full report.

Phase 4 — Deadlines and supplementation

  • Calendar the scheduling order dates; absent an order, disclosures are due 90 days before trial and rebuttals within 30 days of the other side's disclosure, Rule 26(a)(2)(D).
  • Diary the supplementation obligation under Rule 26(e) — but understand supplementation corrects incompleteness; it does not add new opinions after the deadline.
  • Confirm every disclosure was actually served, and keep proof.

Why this matters. Rule 37(c)(1) exclusion is automatic and self-executing unless the failure was substantially justified or harmless. Courts weigh surprise, curability, trial disruption, the importance of the evidence, and the explanation — but the default is exclusion.

Phase 5 — Testing your own expert against amended Rule 702

Before serving, confirm the proponent can show, more likely than not, that:

  • 702(a) — the specialized knowledge will help the trier of fact (not merely restate common sense).
  • 702(b) — the testimony is based on sufficient facts or data. Are the inputs adequate in quantity and quality?
  • 702(c) — the testimony is the product of reliable principles and methods. Is the method accepted, tested, published, error-rated, and standard-governed where those apply? Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993); Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999) (extending gatekeeping to technical and experience-based testimony).
  • 702(d) — the opinion reflects a reliable application of the method to the facts. Did the expert follow the method's own published requirements? Did they rule out alternatives?
  • No overstatement. The Committee Note singles this out: the opinion must be limited to what can reasonably be concluded from a reliable application. Check certainty language.
  • No legal conclusions. Industry standards and practice, yes; "the defendant breached the contract," no.
  • Analytical gap check: walk from data to conclusion step by step and identify where an inference is unsupported. General Electric Co. v. Joiner, 522 U.S. 136 (1997).

Why this matters. The 2023 amendment exists because courts were treating basis and application as weight rather than admissibility, which the Advisory Committee called "an incorrect application of Rules 702 and 104(a)." Your opponent will cite that note; test your own expert against it first.

Phase 6 — Deposing the opposing expert

  • Lock the opinions: "Are those all of the opinions you intend to offer in this case?"
  • Establish every assumption, and get concessions that the opinion changes if an assumption fails.
  • Obtain the methodology's own published standards and walk through compliance step by step.
  • Probe alternatives considered and ruled out, and how.
  • Confirm what the expert did not do, did not review, and does not opine on.
  • Establish compensation, percentage of income from litigation, and prior engagements by the same counsel.
  • Explore prior inconsistent testimony and publications.
  • Do not argue. You are building a Rule 702 motion, not winning a debate.

Why this matters. Exclusion motions are won with the expert's own concessions. A transcript in which the expert admits they did not test the alternative cause is worth more than any competing expert declaration.

Phase 7 — The motion to exclude

  • Attack each opinion separately; partial exclusion is far more commonly granted than wholesale.
  • Frame the challenge under 702(b) (insufficient facts) and 702(d) (unreliable application), and cite the 2023 Committee Note by name.
  • Support with the deposition record and the method's published standards, not with your own expert's disagreement.
  • Address overstatement as an independent ground and ask for limitation as alternative relief.
  • Coordinate timing with summary judgment — file with or before, because if the opinion is what creates the genuine dispute, the court should resolve admissibility first. See Summary Judgment Motion Checklist.
  • Request an evidentiary hearing where reliability turns on how the analysis was actually performed, identifying the specific factual disputes.
  • For damages experts, target: unsupported assumptions, absence of apportionment, benchmark mismatch, causation gaps, double counting, and speculative projections for businesses without operating history.
  • Preserve the objection at trial even after a denied motion in limine, unless the ruling was definitive under Fed. R. Evid. 103(b).

Why this matters. The standard of review is abuse of discretion under Joiner, so these fights are effectively decided in the district court. Reversal is rare in both directions.

Common mistakes

  • Drafting the report for the expert. Drafts are protected under Rule 26(b)(4)(B), but an expert who cannot explain their own analysis is finished on cross.
  • Omitting an opinion from the report and trying to add it at trial.
  • Missing the (B)/(C) classification for a treating physician or employee witness.
  • Relying on "goes to weight." That formulation is now met with the Committee Note calling it incorrect.
  • Attacking only qualifications. Most experts are qualified; the win is usually on application.
  • Filing the exclusion motion after summary judgment is briefed.
  • Overstating certainty in your own expert's report, which invites limitation even when the method is sound.
  • Ignoring supplementation, then producing new analysis on the eve of trial.

Primary authority

Related

This checklist is educational and not legal advice. Expert practice varies by court, judge, and subject matter. Consult qualified litigation counsel about any particular expert or challenge.