The Rule 26 / Daubert expert-report checklist — Springhead Labs

A federal expert report under FRCP 26(a)(2)(B) gets challenged on the boring stuff — a thin basis-and-reasons section, an incomplete list of prior testimony, an exhibit that isn't actually attached. The rule is public; the failure modes are well-worn; and yet a thin report still gets experts limited or excluded under Daubert.

This page walks the Rule 26 expert report requirements as the rule states them, the predictable attack on each one, and the structure that holds up. It's written for the expert producing the report and the attorney reviewing it before it goes out. It is a structure check, not legal advice — your case has a scheduling order and a jurisdiction, and those win.

Rule 26 expert report requirements: the six parts

FRCP 26(a)(2)(B) applies to witnesses "retained or specially employed to provide expert testimony" (and employees whose duties regularly involve giving it). The report must be prepared and signed by the witness, and the rule spells out exactly what it must contain:

A complete statement of all opinions the witness will express, and the basis and reasons for them.
The facts or data considered by the witness in forming them.
Any exhibits that will be used to summarize or support them.
The witness's qualifications, including a list of all publications authored in the previous 10 years.
A list of all other cases in which, during the previous 4 years, the witness testified as an expert at trial or by deposition.
A statement of the compensation to be paid for the study and testimony in the case.

Miss or thin out any one of these and you've handed the other side an easy motion. Rule 37(c)(1) supplies the default consequence: information or opinions that weren't disclosed as Rule 26(a) requires can't be used at trial "unless the failure was substantially justified or is harmless."

How each requirement gets attacked

An expert witness report checklist is only useful if it covers the attack, not just the part. The patterns repeat across dockets:

Opinions, basis, and reasons — the most-attacked component. "Complete" is read literally: an opinion that surfaces at deposition or trial but isn't in the report invites exclusion under Rule 37(c)(1). And a stated opinion with a conclusory basis draws the classic challenge — the report announces a conclusion without showing the reasoning, so the other side argues it's just the expert's say-so.
Facts or data considered — "considered" is broader than "relied on." Listing only the materials cited, and omitting the ones reviewed and set aside, invites the cherry-picking cross: what did you leave out, and why isn't it in your report?
Exhibits — the quiet failure: an exhibit referenced but never attached, or a demonstrative that appears at trial having never appeared with the report. Easy objection, self-inflicted.
Qualifications — two attacks: the gap (qualified in field X, opining on field Y), and the omission (a publication from the 10-year window that cuts against the opinion and wasn't listed — a credibility gift to the cross-examiner).
Prior testimony list — the 4-year list is checkable against public dockets and prior transcripts. An incomplete list is a cheap, verifiable credibility attack; so is a prior transcript where the expert said something different.
Compensation — the attack is vagueness or omission. The rate itself is fair game on bias either way; a missing or evasive statement just adds a compliance problem on top.

A report structure that survives

There's no required template, but reports that survive challenges tend to run the same chain for each opinion, in order — which doubles as a Rule 26(a)(2)(B) structure you can check:

State the opinion plainly, in one or two sentences, up front.
Name the method — what principle, technique, or body of knowledge produced it.
Identify the facts or data the method was applied to in this case.
Show the application — the work connecting method to facts to conclusion, at a level of detail a stranger could follow. This is where most reports are thinnest and most challenges land.
State the result and its limits — what the opinion does and doesn't claim.

Then the housekeeping sections (qualifications, publications, testimony list, compensation, exhibits attached) as their own labeled parts, so nothing required is implied rather than stated.

The Daubert layer: compliance isn't admissibility

A report can contain all six parts and still lose an expert report Daubert challenge, because Rule 26 governs disclosure and Federal Rule of Evidence 702 governs admissibility. Under Rule 702 — amended December 1, 2023 — the proponent must demonstrate to the court that it is more likely than not that the testimony rests on sufficient facts or data, is the product of reliable principles and methods, and that the expert's opinion reflects a reliable application of the principles and methods to the facts of the case.

That last clause is where most challenges aim: not "is the method sound?" but "did the report actually show the method applied to these facts?" A leap from data to conclusion that the report doesn't bridge is the gap a cross-examiner widens and a judge can exclude on. The structural fix is the chain above; the 2023 amendment made explicit that the burden of showing it sits with the side offering the expert.

Two timing facts worth knowing from the rule itself: absent a stipulation or court order, expert disclosures are due at least 90 days before trial (rebuttal experts: within 30 days after the other side's disclosure), per Rule 26(a)(2)(D); and the duty to supplement under Rule 26(e) extends to both the report and the expert's deposition testimony. Your scheduling order almost certainly overrides the default — check it first.

The checklist

Here it is — the whole thing, free, no email required. It compresses everything above into items a report either satisfies or doesn't: the six required parts, the attack each one draws, the per-opinion chain, and the Rule 702 layer. It's built from the current text of FRCP 26, FRCP 37(c)(1), and FRE 702, and it's a structure check, not legal advice — your scheduling order and your jurisdiction control, and nothing here substitutes for counsel reading the report against your case.

It works best walked top to bottom against a finished draft, one item at a time. An item you can't honestly check is an item the other side gets to write a motion about.

Before drafting

☐ The witness is one Rule 26(a)(2)(B) actually covers — retained or specially employed to give expert testimony, or an employee whose duties regularly involve it. (Non-retained experts fall under the lighter 26(a)(2)(C) disclosure instead — but still a disclosure.)
☐ The operative deadline is the scheduling order's, not the rule's 90-day default.
☐ The report is set up to be prepared and signed by the witness, and the substance will be the expert's own — counsel may assist, but a report that reads like the lawyer's brief is a cross-examination theme.
☐ Every opinion the expert will express at trial is slated for the report — nothing reserved for deposition or trial.

Each opinion, in order

☐ The opinion is stated plainly, in one or two sentences, up front.
☐ Every opinion stated has its basis and reasons shown, not asserted.
☐ The method is named — the principle, technique, or body of knowledge that produced the opinion.
☐ The facts or data the method was applied to in this case are identified.
☐ The application is shown at a level of detail a stranger could follow — no unexplained leap from data to conclusion.
☐ The opinion's limits are stated — what it does and doesn't claim.

Facts, data, and exhibits

☐ The facts-or-data section includes materials considered and set aside, not just those relied on — "considered" is the rule's word, and it's broader.
☐ Facts or data supplied by counsel that the expert considered are included — Rule 26(b)(4)(C) doesn't protect those communications.
☐ Assumptions supplied by counsel that the expert relied on are identified — the same exception applies.
☐ Every exhibit the report references is actually attached.
☐ Every exhibit that will summarize or support an opinion is with the report — no demonstrative makes its first appearance at trial.

The housekeeping parts

☐ The qualifications stated cover the field being opined on — no gap between the credentialed field and the opinion's subject.
☐ The publications list spans the full previous 10 years — including the pieces that cut against the opinions.
☐ The prior-testimony list covers all cases from the previous 4 years, trial and deposition both — it's checkable against public dockets, so it has been checked.
☐ Prior transcripts where the expert said something different are accounted for, not left as a surprise.
☐ The compensation statement is specific — the rate and arrangement for both the study and the testimony — not vague, not missing.

The Daubert read

The same report, read against FRE 702 — because a complete disclosure can still carry an inadmissible opinion, and since December 1, 2023 the rule's text puts the more-likely-than-not burden on the side offering the expert:

☐ Each opinion rests on facts or data the report itself shows are sufficient — not just present.
☐ Each opinion is the product of principles and methods the report shows are reliable, not merely names.
☐ Each opinion reflects a reliable application of those methods to this case's facts, with the report bridging every step — the Rule 702(d) clause where most challenges aim.
☐ Each opinion would help a trier of fact understand the evidence or decide a fact actually in issue — not just supply background.

Before it goes out the door

☐ All six 26(a)(2)(B) components appear as their own labeled sections — nothing required is implied rather than stated.
☐ The report reads as the expert's work product, in the expert's voice.
☐ The report has been read the way the other side will read it — hunting the missing exhibit, the conclusory basis, the checkably incomplete list.
☐ The report is signed by the witness.
☐ Nothing the expert will need at trial sits outside the report — Rule 37(c)(1) makes undisclosed opinions and information unusable unless the failure was substantially justified or harmless.

Dates & supplementation

☐ The disclosure date matches the scheduling order — or, absent one, the rule's default: at least 90 days before trial, or within 30 days after the other side's disclosure for rebuttal-only experts.
☐ The Rule 26(e) duty to supplement is on the calendar — it extends to both the report and the expert's deposition testimony.
☐ Any additions or changes are disclosed by the time pretrial disclosures under Rule 26(a)(3) are due.
☐ Drafts stay drafts — Rule 26(b)(4)(B) protects them regardless of the form they're recorded in. The protection covers drafts; it doesn't cover gaps in the final report.

Common questions about Rule 26 expert reports

What happens if an expert report is missing one of the required parts? Rule 37(c)(1) is the default: the undisclosed opinion or information can't be used at trial unless the failure was substantially justified or harmless. Courts also order supplementation, reopen depositions at the producing side's expense, or limit the expert's testimony. None of those outcomes is cheaper than a complete report.

Are draft expert reports discoverable? Generally no in federal court — Rule 26(b)(4)(B) protects drafts of the report "regardless of the form in which the draft is recorded." Rule 26(b)(4)(C) also protects most attorney–expert communications, with three exceptions: communications about compensation, facts or data the attorney provided that the expert considered, and assumptions the attorney provided that the expert relied on.

When is a Rule 26 expert report due? The rule's default is at least 90 days before the trial date (30 days after the opposing disclosure for rebuttal-only experts), but the default only applies absent a stipulation or court order — and most cases have a scheduling order that sets its own dates. The order controls.

Does the expert have to write the report personally? The rule requires the report to be "prepared and signed by the witness," and the advisory committee notes contemplate that counsel may assist with preparation. The substance — the opinions, the basis, the reasoning — must be the expert's own, and a report that reads like the lawyer's brief is itself a cross-examination theme.

Is a Daubert motion the same as a Rule 26 challenge? No. A Rule 26/37 challenge says the disclosure was incomplete or late; a Daubert (Rule 702) challenge says the opinion isn't reliable or wasn't reliably applied to the case's facts. A weak report invites both, and they're often filed together.

Do treating physicians or other non-retained experts need a full report? Not the full 26(a)(2)(B) report — but Rule 26(a)(2)(C) still requires a disclosure stating the subject matter of the testimony and a summary of the facts and opinions the witness will give. "No report required" does not mean "no disclosure required."

The printable version

The checklist above is the whole artifact — complete, free, and yours to use as-is. If you'd rather have it as a formatted one-page PDF for the printer tray, drop your email and we'll send it, plus a short note if FRCP 26, FRCP 37, or FRE 702 actually change. They don't change often; neither will we email often. That's the entire arrangement.

This page is a Springhead Labs experiment, and honesty is part of the format: it's also a test. If people use this checklist — read it, print it, walk a report through it — we build more un-glamorous tools like it for the same audience. If nobody does, it goes in the graveyard and we say so.