The sequence the rules assume, and the one that gets run
An expert engagement is a sequence, and its order is fixed by the rules whether or not anyone follows it. A party decides what the witness is for. It clears the candidate against the parties and the subject matter. It agrees terms in writing. It sends materials. It receives an opinion, discloses it in the form the rules require, defends it at deposition, and — in the small fraction of cases that get there — presents it at trial. Each stage narrows what the stage before it can still decide.
The order in which engagements actually run is different. A name arrives from a colleague, the file goes out that afternoon, a rate is agreed by email, and the retention letter is drafted the week the report is due. Most of the time nothing comes of it. When something does, the difficulty is rarely a drafting error. It is that a decision taken casually in the first week is examined under oath in the ninth month by an examiner whose purpose is to make it look deliberate.
What follows is the frame for that sequence: what each stage settles, which choices stay cheap to revisit, and which are permanent the moment they are made.
Consulting or testifying, decided before anything is sent
The first decision is what the expert is for, and it is the one most often left implicit. Federal practice draws a hard line between the two roles, in the discovery rules rather than the evidence rules.
FRCP 26(b)(4)(D) provides that ordinarily a party may not, by interrogatories or deposition, discover facts known or opinions held by an expert retained in anticipation of litigation who is not expected to testify. The exceptions are narrow: Rule 35(b), and a showing of “exceptional circumstances under which it is impracticable for the party to obtain facts or opinions on the same subject by other means.” That is the strongest protection in the expert rules, because it shields the consultant’s facts and opinions themselves rather than the paperwork around them. A consultant whose answer comes back unhelpful can remain a consultant.
The protection is not portable. Where consulting work reaches a testifying expert, practitioner materials collecting the post-2010 decisions treat the protection over the disclosed material as at serious risk, and describe running both roles through one firm as playing with fire. Even the consultant’s identity is contested: Ager v. Jane C. Stormont Hospital & Training School for Nurses, 622 F.2d 496 (10th Cir. 1980), holds it undiscoverable absent exceptional circumstances; Baki v. B.F. Diamond Construction Co., 71 F.R.D. 179 (D. Md. 1976), holds names may be obtained by interrogatory.
Who retains whom, and what turns on the answer
Retention by counsel rather than by the party is the practice recommended in the ABA’s litigation materials, for the reason above: the relationship the consulting-expert rule contemplates is formed in anticipation of litigation, and counsel is the party to it. The same choice settles something more immediate, which is who owes the expert money.
That question is split by state and turns on agency rather than on evidence law. Courts have held the retaining attorney personally liable where agency was not expressly disclaimed: McCullough v. Johnson, 816 S.W.2d 886 (Ark. 1991), states that an attorney ordering goods or services will be personally liable in the absence of an express disclaimer. Others have held the opposite where the agency was disclosed, as in Free v. Wilmar J. Helric Co., 688 P.2d 117 (Or. Ct. App. 1984).
Neither line is a trap for anyone who addresses the point. One clause naming which of counsel and client is responsible for payment resolves what otherwise resolves by local custom. It is also the clause most often omitted, because it is the only one in the letter about the two people signing it rather than about the case.
The federal disclosure rule is the specification for the search
A party looking for an expert is looking for a witness who can satisfy a written specification, and the specification already exists. FRCP 26(a)(2)(A) requires disclosure of any witness a party may use at trial to present evidence under Federal Rule of Evidence 702, 703 or 705 — the trigger is the evidence rule, not employment, payment or job title. Missing that alone is sanctionable even where nothing was hidden: in Musser v. Gentiva Health Services, 356 F.3d 751 (7th Cir. 2004), the witnesses had been identified but never designated as experts, and the Seventh Circuit affirmed exclusion of the opinion testimony.
From there the rule splits into two tracks. A witness retained or specially employed to provide expert testimony, or an employee whose duties regularly involve giving expert testimony, must produce a signed written report containing all six items in FRCP 26(a)(2)(B). Every other Rule 702, 703 or 705 witness gets the lighter summary disclosure in FRCP 26(a)(2)(C), which counsel drafts and the witness need not sign — and which carries no protection at all for communications with counsel.
Three of the six report items are answerable on the first day of a search rather than at disclosure: qualifications including publications from the previous 10 years, cases in which the witness testified in the previous 4 years, and the compensation to be paid.
Conflicts are a confidentiality doctrine, not a loyalty doctrine
An expert conflict is not a lawyer conflict, and importing the lawyer’s framework gives the wrong answer in both directions. There is no expert analogue to Model Rule 1.7. What disqualifies an expert is confidential information, on the test from Wang Laboratories, Inc. v. Toshiba Corp., 762 F. Supp. 1246 (E.D. Va. 1991).
Wang asks two questions: whether it was objectively reasonable for the first party to conclude that a confidential relationship existed, and whether confidential or privileged information was actually disclosed to the consultant. Affirmative answers to both compel disqualification, and on the facts the expert was disqualified.
The structure is what makes the test usable. A single exploratory call with no documents and no payment does not ordinarily create the relationship, and the opinion is explicit that disqualification is not warranted where no confidential information passed — the safeguard that stops a party tying up a field’s experts by making token contact. The second prong decides most motions: courts ask whether what passed was case-specific, genuinely confidential, not inevitably discoverable and not already public.
A check therefore runs against the full party list including parents and subsidiaries, insurers, counsel of record, the product or transaction at issue, and the candidate’s own clients and board seats. It is a continuing obligation, and objection must be prompt.
The terms that decide the bill are not the rate
The hourly figure is the number everyone negotiates and rarely the number that decides what an engagement costs. The terms around it do more work: whether a retainer is a one-time deposit or a floor topped back up as it is drawn down; how often invoices arrive, since monthly billing is what makes spend visible while it can still be managed; whether appearance days carry minimums and cancellation windows; and who is contractually liable for the money.
One term is not negotiable in substance: compensation for a testifying expert is not contingent on the outcome. ABA Model Rule 3.4(b) forbids offering a witness an inducement prohibited by law, and Comment [3] supplies the content — the common law rule in most jurisdictions is that it is improper to pay an expert witness a contingent fee. Accrued Financial Services, Inc. v. Prime Retail, Inc., 298 F.3d 291 (4th Cir. 2002), held that an arrangement under which prospective expert witnesses shared in the recovery was offering expert testimony for a contingent fee and would violate public policy. Courts differ on the consequence for the testimony — Tagatz v. Marquette University, 861 F.2d 1040 (7th Cir. 1988), leaves it to the jury as a credibility question — which is a reason to avoid the issue rather than test it.
None of it is private: FRCP 26(a)(2)(B)(vi) requires the report to state the compensation to be paid.
Everything the engagement creates is a record
The 2010 amendments extended FRCP 26(b)(3) work-product protection to drafts of any report or disclosure required under Rule 26(a)(2), in any form, and to communications between a party’s attorney and any witness required to provide a Rule 26(a)(2)(B) report. That change is real and routinely overstated in both directions.
It is work-product protection, not privilege, and it arrives entirely by cross-reference. Rule 26(b)(3)(A) is qualified: protected material may still be discovered on a showing of substantial need and inability to obtain the substantial equivalent without undue hardship. Three carve-outs apply to the communications protection — compensation, facts or data the attorney provided that the expert considered, and assumptions the attorney provided that the expert relied on — and the two verbs are not interchangeable. Outside that, little of the file is covered: practitioner materials collecting the post-2010 decisions state that an expert’s own notes are neither drafts nor attorney communications, and that communications with the client, co-experts and subcontractors fall outside the rule.
Underneath sits the disclosure standard. FRCP 26(a)(2)(B)(ii) requires the facts or data considered by the witness, and the 2010 Committee Note reads that as extending to any facts or data considered, “not only those relied upon by the expert.” Material read and rejected was considered. The defensible posture is preservation rather than curation, and several states never adopted the 2010 protections at all.
The calendar is the constraint that decides the rest
FRCP 26(a)(2)(D) opens by requiring disclosures at the times and in the sequence the court orders, and only then supplies the defaults — 90 days before trial, and 30 days after the other party’s disclosure for evidence intended solely to contradict or rebut on the same subject matter. Because Rule 16(b) requires a scheduling order in nearly every civil case, those defaults are gap-fillers rather than operative dates. Reading them as deadlines is a reliable way to be late.
Lateness is enforced through FRCP 37(c)(1): a party that fails to provide information or identify a witness as required by Rule 26(a) or (e) may not use it on a motion, at a hearing or at trial, unless the failure was substantially justified or is harmless. The Ninth Circuit calls the sanction self-executing and automatic — a description of the absence of a motion requirement, not of an absence of discretion — and places the burden of proving harmlessness on the party facing it. Yeti by Molly, Ltd. v. Deckers Outdoor Corp., 259 F.3d 1101 (9th Cir. 2001), affirmed complete exclusion of a damages expert disclosed 28 days before trial, with no violated court order and no bad-faith finding. Every circuit tempers the rule with a four- or five-factor test, and the tests differ enough that identical facts can produce different outcomes in different circuits.
A defect found early is usually cured with a supplemental deposition and some cost-shifting. The same defect found on the eve of trial is a motion nobody wants to argue.
Frequently Asked Questions
When should an expert be retained in a case?
Early enough that the expert can shape what is asked for in discovery, and before anything confidential has been shown to a candidate who is not retained. Timing is driven by the scheduling order rather than by the defaults in Rule 26(a)(2)(D), and the report deadline is the last of several dependent dates: the expert needs the materials, the materials often need a production or a deposition first, and both need requesting. Counsel who work backward from the disclosure date usually find that the first genuinely available week has already passed.Should the expert be retained by counsel or by the client?
Retention by counsel is the practice recommended in the ABA’s litigation materials, because the consulting-expert protection in Rule 26(b)(4)(D) contemplates a relationship formed in anticipation of litigation and counsel is the party to it. The choice also decides who owes the money, and courts split on whether a retaining attorney is personally liable when the client does not pay — compare McCullough v. Johnson, 816 S.W.2d 886 (Ark. 1991), with Free v. Wilmar J. Helric Co., 688 P.2d 117 (Or. Ct. App. 1984). An express clause on payment responsibility settles it.Can a consulting expert later be designated to testify?
It can be done, and it should be planned as a decision that exposes the consulting work rather than as a change of label. The protection in Rule 26(b)(4)(D) attaches to an expert not expected to be called at trial; once the expert testifies, the material that fed the opinion falls under the disclosure standard in Rule 26(a)(2)(B)(ii), which reaches facts or data considered and not merely relied upon. Practitioner materials describe using one firm in both roles as playing with fire, and recommend deciding the designation at the outset.Is everything sent to a testifying expert discoverable?
Not everything, and considerably more than most parties expect. Drafts of the report and communications with retaining counsel receive work-product protection under Rules 26(b)(4)(B) and (C), which is strong but qualified and carries three express exceptions: compensation, attorney-supplied facts or data the expert considered, and attorney-supplied assumptions the expert relied on. Outside that, the expert’s own notes, communications with the client or with other experts, testing records and the underlying data are generally not protected. Several states never adopted the 2010 federal protections at all.Does a conflict check protect the expert or the party?
Both, and it is run for a different reason than a law firm conflict check. The disqualification doctrine turns on confidential information rather than on adverse interests: under Wang Laboratories, Inc. v. Toshiba Corp., 762 F. Supp. 1246 (E.D. Va. 1991), a court asks whether it was objectively reasonable to believe a confidential relationship existed and whether confidential information actually passed. Both must be answered yes. The check is run against parties, parents and subsidiaries, insurers, counsel of record, the product or transaction at issue, and the candidate’s own clients and employers — and it continues through the engagement.What is the most expensive mistake in an expert engagement?
Deciding late what should have been decided first. Designation, conflicts, scope and payment responsibility are cheap to settle in writing at the start and expensive at every later point: a designation changed mid-case exposes the earlier work, a conflict surfacing after the disclosure deadline can leave a party without a disclosed expert and no time to disclose another, and an undefined scope produces analysis nobody asked for alongside analysis nobody has time to finish. None of those failures is a failure of expertise. They are failures of sequence.Published