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Six Practical Tips to Guide You Through the Expert Witness Process

Cory Scott Winter


  • It is easy for litigators to basic tips when dealing with expert witnesses during fast-paced litigation.
  • Taking care to apply the tips in this article will help your next case with an expert witness go more smoothly.
  • At the very least, you’ll be more confident that your expert witness will not give you or your client an unwelcome surprise when called to testify.
Six Practical Tips to Guide You Through the Expert Witness Process
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In our fast-paced practice, litigators might overlook these important tips when considering and dealing with expert witnesses. Implementing these could save you a headache—and your case.

Tip 1: Start Early—Very Early

The minute you learn of your client’s (or prospective client’s) case (even if it hasn’t been filed) is when you should start thinking about experts. Whichever side you represent (or even if you represent multiple sides with a counterclaim or cross-claim), think about what elements must be proven and how expert opinion testimony might help you prove them. Remember, the standard to qualify someone as an expert witness is fairly low, but to be admissible, the expert’s opinion must also be helpful to the trier of fact based on the issues in the case. See, e.g., Schaeffer v. Heidi D. Williams, MD, LLC, No. 2:18-cv-1532-DCN, 2020 U.S. Dist. LEXIS 29131, at *4–5 (D.S.C. Feb. 20, 2020), ECF No. 62, at 3 (“[T]he standard for whether a witness is qualified as an expert is a much lower bar than whether certain expert testimony is admissible under Daubert.”). Ask yourself: “Will my case be stronger at trial with an expert?”

If the answer is yes, there’s no reason to delay. Start researching potential experts. Engaging an expert takes time and client buy-in. Putting off this task could cost you valuable time. Indeed, engaging the right expert during the pleadings stage could allow you to maximize the expert’s knowledge to develop your pleadings, discovery strategy, and early settlement negotiations. None of these potential benefits are available if you don’t take early steps to find and retain an expert.

Tip 2: Don’t Forget Damages

Damages are often an essential element of a cause of action. Because lawyers are so focused on establishing or defending liability, determining how to prove or disprove damages is often put off as “tomorrow’s problem.” That strategy could leave your client with a favorable judgment barely worth the paper it’s printed on if you don’t treat damages as a coequal component of your case. Or, if you’re defending a case, you could end up with an adverse judgment in an amount you never saw coming.

Tip 3: Mind Your Terms of Engagement

Ideally, you should engage the expert using an agreement you prepared. But if you’re engaging an expert through a search firm, the firm may require you to sign a form agreement. Either way, consider and properly address the following:

  • Who will pay the expert? If you don’t want to get stuck with the bill, which can easily run into the tens of thousands, ensure that your expert engagement states that the client is responsible for payment. Otherwise, the expert will demand payment from you even if your client has not paid for this costly expense. Failing to pay the expert could result in the expert stopping work, putting you in a tough and expensive ethical quandary.
  • What work is the expert allowed to perform and when? If you’re not careful, the expert may take your signed agreement and start reviewing documents or running to ground every possible theory. Maybe that’s what you want. If not, you should specify that the expert will perform work only at your explicit written direction. Then, when it comes time for you to give that direction, provide that direction in detail, including parameters for sources to be reviewed and a limitation on the number of hours to be spent.
  • Is your engagement confidential? It should be. This may be obvious, but your expert should keep all information about the engagement, and the fact of engagement, confidential. Novice experts, especially those who landed their first engagement (yours), may not appreciate that they shouldn’t publicize it on the internet or elsewhere. Publication may cost you a competitive advantage, especially if you didn’t intend to disclose your expert’s identity until later in the case. Don’t assume. Ensure your agreement contains confidentiality provisions that cover your expectations in detail.

Tip 4: Ruthlessly Scrutinize Your Expert’s Report

Your expert and the expert’s analysis are not infallible. Your adversary is not going to review your expert’s report, throw up their hands, and agree to whatever your client wants. Your adversary is going to fight back with their own expert’s report or with attempts to undermine your expert’s report.

You can’t defend your expert’s report if you don’t ruthlessly scrutinize the draft. Ensure your expert “shows their work” by including these entries:

  • What is your expert’s field or fields of expertise? Being a “medical doctor” is not a field of expertise. Is it general medicine, internal medicine, or something else? What does that scope of expertise entail? Be sure that you and your expert are aligned on the expert’s field of expertise and that the description is accurate, or risk your expert’s disqualification.
  • What sources did the expert rely on? This includes both the underlying record (i.e., discovery documents like document productions and deposition transcripts) and secondary sources. Cite the record and sources with specificity and accuracy. If your client’s document production consists of 100,000 pages and your expert reviewed only 500 of those, cite which pages were reviewed. Otherwise, be prepared for opposing counsel to learn that during expert discovery, which opposing counsel is entitled to learn (but you may not want to share).
  • What assumptions did your expert make in evaluating the facts or making any conclusions? If the expert assumed liability on behalf of a party, state that. If the expert assumed the credibility of one or more witnesses, state that. Whatever the assumptions, your expert’s report should state them with specificity.
  • Can you follow the expert’s logic? Your expert’s analysis should explain how  your expert got from A to Z. If there are any gaps, which could suggest an assumption, the expert must expound. You need to be able to follow your expert’s analysis and agree with it. If you can’t, you need to rectify the issue, because it may come up in discovery, via a motion in limine, or at trial.
  • What are your expert’s conclusions? You hired the expert to offer expert opinion, so what exactly are those opinions? While your expert’s opinion can touch on the “ultimate question” (Fed. R. Evid. 704), consider having the expert opine on subparts of that question. Whatever you do, ensure that your expert’s conclusions are specifically and easily identifiable.

Tip 5: Do Not Skimp on Preparing Your Witness for Deposition

Some expert witnesses who previously testified at a deposition mistakenly believe they don’t need to be prepped for testimony. They might be right, but if your case hinges on their testimony—and many cases involving experts do—are you willing to take the chance of having an ill-prepared expert testify? You shouldn’t be.

Your expert may not know all facets of your case, including how other witnesses are expected to testify. It’s important you help your expert understand the limits of his or her testimony and how it relates to your case strategy. Similarly, ensure your expert understands that his or her testimony should always relate directly to the report.

It’s great that your expert may have testified before, but your expert likely hasn’t testified for your client. Even if your expert has, it’s not for the current case. Bottom line: Don’t allow your expert’s confidence (and perhaps arrogance) blind your common sense in fully preparing your expert for deposition.

Tip 6: Ensure That Your Expert Knows the Report

Your expert doesn’t need to memorize his or her report, but the expert needs to nimbly testify about the meanings of specific words and phrases selected by opposing counsel, often out of context. An expert who doesn’t know what certain words or phrases in the report mean could signal a lack of knowledge, paving the way for a motion in limine. The expert also needs to be ready to testify on choices the expert made (or didn’t make) in his or her analysis and conclusions. Critically, the expert must be ready to testify on how hypothetical facts might affect his or her analysis and conclusions, if at all.


Mindfully applying these tips will hopefully help your next case with an expert witness go more smoothly. At the very least, you’ll be more confident that your expert witness will not give you or your client an unwelcome surprise when called to testify.