Expert Deposition Preparation Checklist: A Practical Checklist

Summary. This checklist turns expert deposition practice into concrete tasks for both sides of the table, organized in the order the work happens. It begins with the steps both sides should take before reports are exchanged, including an expert stipulation, protective order provisions for expert access, and the separation of consulting and testifying roles. The taking-side phases cover auditing the report against Rule 26(a)(2)(B), collecting the expert's file by request and subpoena, settling the Rule 26(b)(4)(E) fee, researching the expert, building an outline organized by Rule 702 element, conducting the examination, and turning the transcript into motions. The defending-side phases cover preserving the file, responding to the notice and subpoena, preparation sessions built around the three Rule 26(b)(4)(C) exceptions, objections and instructions, errata, supplementation, and the Daubert hearing. Short sub-checklists address treating and hybrid witnesses, remote and foreign depositions, dual-hat experts, patent damages experts, and software experts, followed by red flags, an FAQ, and practical takeaways.

Most expert depositions are decided by a task someone forgot: the subpoena rider nobody served, the invoice entry nobody read, the assumption nobody wrote down. This checklist is the list of those tasks. It is built for the lawyer running expert discovery and for the client or in-house lawyer who wants to know whether it is being run well.

The short answer

If you are taking the deposition, the work that matters most is getting the expert's native files a week early, agreeing on the fee before the notice, organizing the outline by opinion and by element of Fed. R. Evid. 702, asking about the three categories of attorney communications that are discoverable, and locking the opinions at both ends of the day. If you are defending, the work that matters most is structural and early: separate consultants from testifiers, preserve everything the expert considered, write a real assumptions section, keep invoices neutral, prepare the expert in a full-length session, and fix substantive mistakes by supplement rather than errata.

For the doctrine behind each item, see Expert Depositions: Taking Apart the Opinion, Protecting Your Own Expert, and Building the Daubert Record; for the step-by-step narrative, see Taking and Defending an Expert Deposition: A Practical Guide.

How to use this checklist

Phases 1 and 2 apply to both sides. Phases 3 through 8 are for the lawyer taking the deposition; Phases 9 through 14 are for the lawyer defending it. Most lawyers in expert discovery are doing both at once, so keep a copy of each track for every expert in the case. The special-situation sub-checklists at the end apply on top of the main tracks.

Phase 1: Before reports are exchanged (both sides)

Propose an expert stipulation under Fed. R. Civ. P. 29 covering drafts, notes, attorney communications, privilege logging, production timing, and fee terms. Note: the 2010 amendments protect drafts and most attorney-expert communications in federal court, but a stipulation removes ambiguity, can extend protection to notes, and settles whether protected material must be logged. It also matters if any related proceeding is in a state court without equivalent protection.
Negotiate per-report deposition time in the scheduling order under Fed. R. Civ. P. 16 for experts who cover several patents, products, or both liability and damages. Note: the default is one day of seven hours under Fed. R. Civ. P. 30(d)(1); fighting for more time at hour six rarely works.
Confirm that the protective order has a workable procedure for disclosing experts who will see confidential information, with a short objection period. Note: an expert who cannot see the other side's documents until a dispute is resolved cannot write a complete report. See Protective Order and Sealing Checklist.
Serve Fed. R. Civ. P. 34 requests early in discovery that define "expert materials" to include everything a testifying expert considered and the expert's communications with anyone other than counsel.
Calendar every expert deadline: opening reports, rebuttal reports (30 days after the other side's disclosure by default under Fed. R. Civ. P. 26(a)(2)(D)), reply reports if allowed, the close of expert discovery, Daubert and summary judgment motions, and Rule 26(a)(3) pretrial disclosures.

Phase 2: Structure your own experts (both sides, before anyone is designated)

Decide, for each expert, whether the role is consulting or testifying, and keep the roles in different people where possible. Note: a consultant's facts and opinions are protected under Rule 26(b)(4)(D) absent exceptional circumstances; designation as a testifier opens overlapping consulting work, as in Yeda Research & Development Co. v. Abbott GmbH & Co. KG, 292 F.R.D. 97 (D.D.C. 2013). Some courts also protect a consultant's identity, Ager v. Jane C. Stormont Hospital & Training School for Nurses, 622 F.2d 496 (10th Cir. 1980).
Retain testifying experts through counsel with an engagement letter that states the assignment, rates, billing practices, and confidentiality duties, written on the assumption it will be produced.
Send each testifying expert a written preservation instruction covering notes, data, test results, models, code, and communications with anyone other than counsel. Note: the expert must retain and disclose materials considered even if not relied on; a retention policy is no excuse, Fidelity National Title Insurance Co. v. Intercounty National Title Insurance Co., 412 F.3d 745 (7th Cir. 2005).
Ask each expert to keep invoice entries neutral and factual. Note: compensation is an exception to the Rule 26(b)(4)(C) protection, so invoices are produced and sometimes read aloud.
Route the expert's contacts with client personnel through counsel, or have the expert keep a log of whom she spoke with and what she learned. Note: Rule 26(b)(4)(C) protects only communications with the party's attorneys.
Identify any non-retained experts (treating physicians, the client's engineers) and decide whether each needs a Rule 26(a)(2)(C) summary or, because the opinions go beyond what the witness learned on the job, a full report. Note: see the hybrid witness sub-checklist below.

Phase 3: The day the opposing report arrives (taking side)

Read the report the day it is served, and send it to your own expert the same day.
Audit the report against the six elements of Rule 26(a)(2)(B): opinions with basis and reasons; facts or data considered; exhibits; qualifications with ten years of publications; four years of prior testimony; compensation. Note: the report must be complete enough that you are not forced to depose the expert to avoid an ambush at trial, Salgado v. General Motors Corp., 150 F.3d 735 (7th Cir. 1998). Send a deficiency letter for any missing element and keep a copy for a later Fed. R. Civ. P. 37(c)(1) motion.
List every assumption the report states or implies, and mark which ones appear to come from counsel.
List every opinion as a numbered sentence; this list becomes the backbone of the outline and the lock-in exhibit.
Serve the deposition notice under Rule 30(b)(1), stating the recording method under Rule 30(b)(3) and whether the deposition will be videotaped. Note: the deposition of a report-required expert may be taken only after the report is served, under Rule 26(b)(4)(A).
Serve a Fed. R. Civ. P. 45 document rider with the notice, with a production date seven to ten days before the deposition, and serve it on every party under Rule 45(a)(4). Note: some courts quash stand-alone document subpoenas to an opponent's retained experts, Marsh v. Jackson, 141 F.R.D. 431 (W.D. Va. 1992); pairing the rider with the notice is safer.
Propose fee terms in writing: testimony rate, preparation time and cap, travel, transcript review, cancellation, invoice timing. Note: the deposing party pays a reasonable fee under Rule 26(b)(4)(E) unless manifest injustice would result; courts split on preparation time.
If anyone will appear remotely, obtain a stipulation or order under Rule 30(b)(4) that names the platform and the exhibit procedure.

Phase 4: Collect and review the expert's materials (taking side)

Request the engagement letter, invoices, and time entries.
Request every document, data set, model, spreadsheet, script, and repository the expert considered, in native format with formulas and metadata intact. Note: "considered" includes anything the expert generated, reviewed, reflected on, read, or used, even if rejected, Synthes Spine Co. v. Walden, 232 F.R.D. 460 (E.D. Pa. 2005).
Request testing protocols, raw results, inspection notes, photographs, and interview notes.
Request the expert's communications with anyone other than the retaining lawyers, including the client's employees and other experts. Note: the 2010 amendments did not create a general shield for testifying expert materials, Republic of Ecuador v. Mackay, 742 F.3d 860 (9th Cir. 2014); Republic of Ecuador v. Bjorkman, 735 F.3d 1179 (10th Cir. 2013).
Request any written statement of assumptions counsel provided.
Do not request drafts or counsel's comments on drafts unless the stipulation allows it.
Check the production against the report's considered-materials list item by item, and send a deficiency letter within two days for anything missing. Note: the report need not attach working notes, Gillespie v. Sears, Roebuck & Co., 386 F.3d 21 (1st Cir. 2004), which is exactly why the request and the rider matter.
Have your own expert open the native files, rerun the key calculations, and flag any step that cannot be reproduced.
If production is refused, meet and confer immediately and move to compel under Rule 37(a); ask that the deposition be held open if the motion cannot be decided first.

Phase 5: Research the expert (taking side)

Collect the prior testimony list and search dockets for testimony outside the four-year window and since the report was signed.
Obtain prior transcripts and reports on the same subject from other lawyers, and check whether earlier protective orders limit their use.
Search for prior Rule 702 rulings involving the expert, and read every opinion that excluded or limited her testimony.
Collect publications, slide decks, course materials, patents, and conference talks; mark every statement of method, error rate, or standard.
Verify degrees, licenses, certifications, and employment history against the CV.
Capture and preserve the expert's public online statements on the subject before they change.
Identify how often the expert has worked for this firm, this client, or this side of the caption. Note: bias discovery is legitimate but bounded; Behler v. Hanlon, 199 F.R.D. 553 (D. Md. 2001) allowed discovery of the percentage of income from expert work and retention patterns but rejected tax returns.
Ask your own expert for a short memo on the weakest steps in the analysis, the published standards the report departs from, and the questions a peer reviewer would ask.

Phase 6: Build the outline and exhibits (taking side)

Organize the outline by opinion, and within each opinion by the Rule 702 elements: sufficient facts or data, reliable principles and methods, and reliable application. Note: since December 1, 2023, the proponent must show each element is more likely than not satisfied, and sufficiency of the basis and reliability of the application are admissibility questions, not weight questions. EcoFactor, Inc. v. Google LLC, 137 F.4th 1333 (Fed. Cir. 2025) (en banc) asks whether the facts the expert actually relied on are sufficient, not whether the whole record could support the opinion.
For each opinion, write the funnel: an open question, follow-ups, closed leading questions, and the catch-all ("Is there anything else you relied on?").
For each step of each analysis, write the question that asks the expert to state the step before you test it. Note: "any step that renders the analysis unreliable" renders the testimony inadmissible, In re Paoli Railroad Yard PCB Litigation, 35 F.3d 717 (3d Cir. 1994).
Write the Daubert-factor questions for each method: testing, peer review and publication, error rate, controlling standards, general acceptance, as listed in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993).
Write the Kumho rigor question for each method: "What would you have done if a client hired you to answer this outside of litigation?" Note: Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999) asks whether the expert brings the same intellectual rigor to the courtroom as to the field.
Write a "would your opinion change if" question for every assumption, using facts already in the record.
Write the "name the standard" questions: title, edition, section, and where the standard says what the expert says it says. Note: in Sardis v. Overhead Door Corp., 10 F.4th 268 (4th Cir. 2021), an expert who could not identify the testing standards he invoked helped produce a judgment for the defendant on appeal.
Write the gap questions: where the analysis moves from data to conclusion, ask what connects them. Note: an opinion "connected to existing data only by the ipse dixit of the expert" may be excluded, General Electric Co. v. Joiner, 522 U.S. 136 (1997).
Write the reliance-on-others questions: who ran each calculation, who supplied each input, and whether the expert could have done the work herself. Note: an expert may not serve as "the mouthpiece of a scientist in a different specialty," Dura Automotive Systems of Indiana, Inc. v. CTS Corp., 285 F.3d 609 (7th Cir. 2002).
Write the learned-treatise foundation questions for each standard text you may use at trial under Fed. R. Evid. 803(18).
Sequence each impeachment as commit, then confront, then explain.
Write the opening and closing lock questions: all opinions stated; no further work planned; nothing else relied on; no opinion on the listed topics outside the assignment.
Assign a time budget to each module and total it to six and a half hours, leaving a reserve.
Prepare exhibits: the report as the first exhibit, the CV, invoices, the considered-materials list, key documents, impeachment items, and printed native-file outputs; prepare enough copies or test the exhibit platform.

Phase 7: At the deposition (taking side)

State any stipulations on the record in full; do not agree to "the usual stipulations."
Ask whether the expert brought documents; if so, ask for them and mark them.
Ask what the expert reviewed to prepare and with whom she met, how long, and who attended. Note: writings used to refresh recollection may be ordered produced under Fed. R. Evid. 612.
Ask whether the expert has done any new work or formed any new opinion since signing the report.
Cover retention, assignment, and compensation, including the date of first contact and any consulting work before designation.
Ask about the three discoverable categories of attorney communications: compensation, facts or data provided and considered, assumptions provided and relied on.
Do not ask about drafts or counsel's comments on drafts.
Run each opinion's funnel and close it with the catch-all question.
Ask the change question for each assumption, and record the answer precisely.
Move to strike nonresponsive answers on the record; objections to the form of an answer are waived if not made at the deposition under Fed. R. Civ. P. 32(d)(3)(B).
Keep a running log of time consumed by nonresponsive answers, breaks, and obstruction.
When the defending lawyer instructs the witness not to answer, put the question and the stated basis on the record, ask whether the witness will follow the instruction, and move on. Note: instructions are permitted only to preserve a privilege, enforce a court order, or present a Rule 30(d)(3) motion, Redwood v. Dobson, 476 F.3d 462 (7th Cir. 2007).
When the expert says she would have to look, hand her the document and wait, or ask whether any document would change the answer and which one.
Repeat the lock and close the doors at the end of the day.
If documents are outstanding, state on the record that the deposition is held open for questioning about them.

Phase 8: After the deposition (taking side)

Digest the transcript within three business days, organized by opinion and Rule 702 element, with page and line citations for every concession.
Draft the motion sections while the testimony is fresh.
Calendar the Rule 30(e) errata deadline (30 days after the reporter's notice, if review was requested) and review any errata the day they arrive.
Challenge contradictory substantive errata. Note: see Thorn v. Sundstrand Aerospace Corp., 207 F.3d 383 (7th Cir. 2000) and Hambleton Bros. Lumber Co. v. Balkin Enterprises, Inc., 397 F.3d 1217 (9th Cir. 2005).
If a supplemental report adds new analysis, move to strike under Rule 37(c)(1), seek a continued deposition at the proponent's expense, or both. Note: supplementation corrects inaccuracies and fills gaps with information not previously available; it does not bolster, Akeva L.L.C. v. Mizuno Corp., 212 F.R.D. 306 (M.D.N.C. 2002). On harmlessness, see Yeti by Molly, Ltd. v. Deckers Outdoor Corp., 259 F.3d 1101 (9th Cir. 2001) and Southern States Rack & Fixture, Inc. v. Sherwin-Williams Co., 318 F.3d 592 (4th Cir. 2003).
Pay the expert's invoice under the agreed terms, or move under Rule 26(b)(4)(E) if the amount is disputed.
Map each concession to the summary judgment element it defeats, and to the trial cross outline.
Mark designation candidates for trial; see the Deposition Designation and Errata Checklist.

Phase 9: Respond to the notice and subpoena (defending side)

Confirm the date, place or platform, recording method, and attendees in writing.
Confirm the fee terms in writing before the deposition, including preparation time, travel, and transcript review.
Serve written objections to the Rule 45 rider before the earlier of the compliance date or 14 days after service, as Rule 45(d)(2)(B) requires. Note: object to drafts and attorney communications under Rule 26(b)(4)(B) and (C), and to anything outside the expert's assignment; produce the rest. See the Rule 45 Subpoena Response Checklist.
Decide whether withheld drafts and communications must be logged, and follow the stipulation; if there is none, see Preparing a Privilege Log.
Produce the considered materials completely, in native format, by the agreed date.
Produce the engagement letter and invoices.
If you need a protective order limiting the deposition, move before the deposition date.

Phase 10: Audit your own expert's report and file (defending side)

Confirm the report states every opinion the expert will offer at trial, with basis and reasons for each. Note: testimony that departs from the report can be struck; in Rembrandt Vision Technologies, L.P. v. Johnson & Johnson Vision Care, Inc., 725 F.3d 1377 (Fed. Cir. 2013), an expert who described a different test method at trial lost his testimony.
Confirm the considered-materials list is complete, including interviews with client personnel and materials the expert reviewed and set aside.
Confirm the assumptions section lists every assumption counsel supplied, with the expert's reason for treating each as reasonable and any check she performed.
Confirm the prior-testimony list covers four full years and the publication list covers ten.
Read every invoice entry.
Confirm that every exhibit, chart, and calculation can be explained by the expert personally, including those prepared by staff.
Identify any opinion the expert cannot defend under Rule 702, and decide now whether to withdraw it.

Phase 11: Preparation sessions (defending side)

Schedule preparation close to the deposition, with at least one session as long as the deposition.
Assemble the preparation binder: report and exhibits, considered materials, opposing reports, key case documents, the expert's prior testimony and publications on the subject, CV, engagement letter, invoices.
Keep privileged material out of the binder. Note: writings used to refresh recollection can be ordered produced under Rule 612.
Explain the mechanics: attendees, duration, video, breaks, and the rule against breaks while a question is pending except to discuss privilege.
Explain the deposing lawyer's goals: locking opinions, closing doors, finding assumptions, testing methods, and collecting bias material.
Teach the three discoverable categories of attorney communications, and tell the expert you will instruct her not to answer questions about drafts and counsel's comments.
Walk through every opinion: page, one-sentence statement, method in three sentences, key support.
Rehearse scope answers for questions outside the assignment ("I was not asked to analyze that and have not formed an opinion").
Rehearse hypotheticals, lists, and absolutes, and the honest answer when the expert would need to analyze something new.
Review every publication and prior report the other side may use, and prepare explanations for apparent inconsistencies.
Review bias questions: rate, hours, total billed, percentage of income from expert work, prior engagements with this firm and client.
Run a full-length mock examination by a lawyer who has not worked with the expert.
Remind the expert that the opinions must be her own; ABA Model Rule of Professional Conduct 3.4(b) bars assisting a witness to testify falsely.
Tell the expert to bring nothing to the deposition.
For a remote deposition, test the platform, camera framing, lighting, audio, and the exhibit procedure with the expert.

Phase 12: At the deposition (defending side)

Before the record opens, confirm the stipulations and the exhibit procedure, and that the expert has only permitted materials.
Object to form concisely ("Objection, form") and stop; speaking objections violate Rule 30(c)(2) and invite sanctions under Rule 30(d)(2).
Instruct not to answer only to protect privilege or work product (for example, counsel's comments on a draft), to enforce a court order, or to present a Rule 30(d)(3) motion.
If you invoke Rule 30(d)(3), suspend the deposition and file the motion promptly.
Ask for breaks roughly every hour, never while a question is pending except to address privilege.
Know your court's rule on conferring with the witness during breaks. Note: Hall v. Clifton Precision, 150 F.R.D. 525 (E.D. Pa. 1993) allowed questioning about break-time conferences; many courts protect them.
Decide on redirect: ask only to correct a genuine error or an answer produced by a misleading question, and only if you know the answer.
Request, on the record, that the witness be allowed to review the transcript under Rule 30(e).
Note any request by the taking lawyer to hold the deposition open, and respond on the record.

Phase 13: Errata, supplementation, and continued depositions (defending side)

Send the transcript to the expert the day it arrives and calendar the 30-day errata deadline.
Correct transcription errors and plain misstatements on the errata sheet, with a reason for every change. Note: courts require reasons and can strike changes without them, EBC, Inc. v. Clark Building Systems, Inc., 618 F.3d 253 (3d Cir. 2010).
Do not use errata to contradict substantive testimony. Note: the Tenth Circuit treats contradictory errata like sham affidavits, Garcia v. Pueblo Country Club, 299 F.3d 1233 (10th Cir. 2002), and has rejected an expert's errata that substantially qualified his testimony, BancFirst ex rel. Estate of M.J.H. v. Ford Motor Co., 422 F. App'x 663 (10th Cir. 2011).
For a genuine substantive error, serve a Rule 26(e) supplement that explains the correction, before the Rule 26(a)(3) deadline, and offer a short continued deposition.
Keep the supplement to correction; do not add new analysis or stronger opinions, Keener v. United States, 181 F.R.D. 639 (D. Mont. 1998).

Phase 14: The Daubert hearing and trial readiness (defending side)

Read the transcript as the judge will and list every question the expert could not answer cleanly.
Decide for each gap: an explanatory declaration consistent with the testimony, live testimony at a Fed. R. Evid. 104(a) hearing, or narrowing the opinion.
Check every declaration against the transcript for contradictions. Note: an unexplained contradiction invites the sham-affidavit rule of Cleveland v. Policy Management Systems Corp., 526 U.S. 795 (1999).
Consider withdrawing any opinion that cannot meet the preponderance standard, to protect the rest.
Assess whether the expert's deposition may be played at trial under Rule 32(a)(4), and whether a separate trial-preservation deposition is needed.
Remember the end state: if the testimony is excluded on appeal and the rest of the evidence is insufficient, the court may direct judgment, Weisgram v. Marley Co., 528 U.S. 440 (2000).

Special situations

Treating physicians, employees, and other hybrid witnesses

Determine whether each opinion was formed in the course of the witness's ordinary work or for the litigation. Note: some circuits require a full report when a treating physician's causation opinion was formed outside treatment, Meyers v. National Railroad Passenger Corp., 619 F.3d 729 (7th Cir. 2010), or based on materials from counsel, Goodman v. Staples the Office Superstore, LLC, 644 F.3d 817 (9th Cir. 2011).
Taking side: depose the witness on when and how each opinion was formed, and what litigation materials the witness reviewed.
Defending side: remember that counsel's communications with a non-retained witness are not protected by Rule 26(b)(4)(C), PacifiCorp v. Northwest Pipeline GP, 879 F. Supp. 2d 1171 (D. Or. 2012).
For a nonparty witness, serve a Rule 45 subpoena and tender the fee and mileage of 28 U.S.C. § 1821, and negotiate any professional fee in advance.

Remote and foreign depositions

Obtain a Rule 30(b)(4) stipulation or order naming the platform, the exhibit procedure, and the witness's room conditions.
Confirm that the officer can administer the oath under Fed. R. Civ. P. 28 where the witness sits.
For a witness abroad, choose the Rule 28(b) route (treaty, letter of request under 28 U.S.C. § 1781, notice, or commission) and check whether the country restricts depositions of willing witnesses. Note: the Hague Evidence Convention is not a mandatory first resort for discovery from parties, Societe Nationale Industrielle Aerospatiale v. United States District Court, 482 U.S. 522 (1987).

Dual-hat and formerly consulting experts

Taking side: ask when the expert was first contacted and what work she did before being asked to write a report.
Taking side: request the consulting-phase file where it overlaps the testimony, citing Yeda.
Defending side: decide before designation whether the consulting file will be produced, and if not, designate someone else.

Patent damages experts

Ask how each comparable license is economically and technologically comparable, and how each lump sum was converted to a rate.
Ask which Georgia-Pacific factors moved the rate, in which direction, and by how much. Note: a superficial recitation of the factors followed by a number does not support a verdict, Whitserve, LLC v. Computer Packages, Inc., 694 F.3d 10 (Fed. Cir. 2012).
Ask how the rate was derived step by step, Exmark Manufacturing Co. v. Briggs & Stratton Power Products Group, LLC, 879 F.3d 1332 (Fed. Cir. 2018).
Ask where any starting split came from, other than a rule of thumb, Uniloc USA, Inc. v. Microsoft Corp., 632 F.3d 1292 (Fed. Cir. 2011); VirnetX, Inc. v. Cisco Systems, Inc., 767 F.3d 1308 (Fed. Cir. 2014).
Ask what evidence shows the patented feature drives demand if the base is the whole product, Power Integrations, Inc. v. Fairchild Semiconductor International, Inc., 904 F.3d 965 (Fed. Cir. 2018).
For standard-essential patents, ask how the value of the technology was separated from the value of standardization, Ericsson, Inc. v. D-Link Systems, Inc., 773 F.3d 1201 (Fed. Cir. 2014).
See the Patent Damages Checklist for the full damages framework under 35 U.S.C. § 284.

Software and copyright experts

Ask how modules were selected for comparison and whether the selection would be used outside litigation.
Ask the expert to identify the filtration criteria (efficiency, external constraints, public domain and open-source material, scenes a faire) and the sources for each, following Computer Associates International, Inc. v. Altai, Inc., 982 F.2d 693 (2d Cir. 1992) and 17 U.S.C. § 102(b).
Confirm whether the expert offers any opinion on the ordinary-observer or intrinsic comparison, and close the door if not.
Ask about interviews with developers, which are discoverable communications with non-attorneys.
See the Copyright Infringement Claim Evaluation Checklist for the elements the expert's work must connect to.

Red flags that should change your plan

The report's assumptions section says only "counsel instructed me to assume," with no reasons.
A key number (a rate, a percentage, an allocation) appears with no calculation behind it.
The expert relied on another expert's figure that she cannot explain.
The production omits native files, or the formulas have been pasted as values.
The expert was a consultant before she was designated.
Invoices show substantial hours before the expert's stated retention date.
The expert's prior publication or testimony takes the opposite position.
A "rebuttal" report contains new affirmative opinions.
The defending lawyer will not commit to fee terms or production dates.

Frequently asked questions

Which side pays the expert for the deposition? The deposing side pays a reasonable fee for the time spent responding, unless manifest injustice would result; preparation time depends on the court and the agreement.

Can we ask about the expert's drafts? No, absent a stipulation or a rare showing of substantial need. Ask about compensation, facts or data counsel provided that the expert considered, and assumptions counsel provided that the expert relied on.

What if the expert shows up with notes? Ask for them and mark them; materials used at the deposition or to refresh recollection are generally discoverable.

How do we fix a mistake in our expert's testimony? Transcription errors go on the errata sheet with reasons. Substantive errors are better handled by a Rule 26(e) supplement that explains the correction, with an offer of a short continued deposition.

Can the deposition be used at trial? For impeachment, yes. As substantive evidence, generally only if the expert is unavailable under Rule 32(a)(4), including being more than 100 miles away, or by agreement.

Practical takeaways

Get native files a week ahead; your own expert should open them before you write the outline.
Settle the fee before the notice, including preparation time.
Outline by opinion and Rule 702 element, with a time budget and a lock at both ends.
On defense, the decisive tasks happen at retention: separate roles, preservation, neutral invoices, complete assumptions.
Use errata for corrections and supplements for substance.

This document is general information, not legal advice for any particular situation; the law changes, and the facts matter.