10 Questions Attorneys Should Ask Before Retaining an Expert Witness

Retaining the right expert witness is not just about credentials. It is about admissibility, credibility, and whether the expert can carry the case if it moves beyond an initial review.

As Celia Guo put it, “I would approach every expert retention assuming that this is the expert you’re going to need for trial.” That mindset can prevent a common and expensive problem: retaining someone for a preliminary opinion, only to learn later that they cannot testify, travel, or withstand scrutiny.

1. Is this expert’s experience truly aligned with the issues in this case?

Start with fit, not prestige.

A strong CV does not help much if the expert’s background does not match the actual facts, time period, or practice setting at issue. Guo noted that attorneys should ask more than whether the expert practices in the field now. They should ask, “Did you practice it at the time period that is relevant for this case?”

That matters in cases where the standard of care is tied to a specific date, setting, or resource level. A neonatologist who works only in a Level IV NICU may not be the right fit for a case arising from a Level II NICU.

2. Have you ever been challenged or excluded?

This is one of the most common threshold questions, and for good reason.

Guo said attorneys regularly ask, “Have you ever been challenged?” and whether the expert has been excluded under Daubert. The goal is not necessarily to disqualify anyone who has faced a challenge. It is to understand what happened, why, and whether the issue could surface again in your case.

Ask for specifics:

• What was the subject of the challenge?
• Was the testimony limited or excluded?
• What methodology was at issue?
• How has the expert addressed that issue since?

3. Have you taken positions in other matters that could contradict this case?

Prior testimony, reports, and publications can become impeachment material quickly.

Guo described this as a core screening question: has the expert “testified on a matter where your opinion in that matter directly contradicts the case that they’re currently discussing”?

Publications matter too. She gave the example of a traffic engineering expert who had written that bus stops should include concrete bollards. In a case involving a bus stop without those protections, that publication could undermine a defense position.

Ask directly:

• Have you published anything inconsistent with our case theory?
• Have you testified to the opposite position before?
• Are there articles, lectures, or public statements we should review first?

4. Can you provide a list of prior cases and testimony?

Do not rely on general assurances.

Request a list of prior cases, testimony history, and, where available, the expert’s Rule 26 materials. According to Guo, experienced experts often have these materials readily available.

This helps you assess:

• subject-matter overlap
• plaintiff/defense balance
• frequency of testimony
• prior outcomes and recurring attack points

5. Are there any conflicts, including personal ones?

Conflicts are not always obvious.

Guo stressed the importance of asking about both legal and personal conflicts. An expert may have no formal conflict with a named party, yet still have ties that affect independence. She cited examples like prior grant funding from a pharmaceutical company or professional discomfort arising from relationships adjacent to the defendant.

Ask beyond named parties:

• insurers
• parent companies
• affiliates
• supervisors
• mentors
• grant sponsors

And ask the practical question Guo recommends: if you had to testify in person on the record against this individual or institution, would you feel comfortable doing it?

6. Are you available for the full life cycle of the case?

Availability is often treated as a minor issue until it becomes a major one.

Guo noted that some attorneys ask about deadlines and travel on every call, while others skip it entirely. That omission creates friction later, particularly when an expert is willing to review records but unwilling to appear for deposition or trial.

Confirm:

• ability to meet deadlines
• deposition availability
• trial hold availability
• travel restrictions
• in-person versus remote limitations

7. What does your fee schedule look like?

Fee issues should be addressed early and clearly.

Guo said she would “100% of the time” ask for a clear fee schedule. That includes not just hourly rates, but how the expert handles annual increases, expedited work, travel, cancellations, and minimum billing increments.

Budget surprises often come from terms that were never discussed.

8. What materials do you need to form a reliable opinion?

A credible opinion depends on sufficient data and clearly stated assumptions.

Before retention, ask what records, testing, photographs, policies, depositions, or other materials the expert will need. Also ask what limitations could prevent a final opinion.

This helps frame scope and avoids late-stage problems when key facts are missing.

9. How do you respond to the other side’s theory?

One of the best ways to pressure-test an expert is to present the competing narrative.

Guo explained that no single question reveals whether someone will perform well under pressure. Instead, attorneys should walk through the case theory, present the likely opposing view, and ask the expert to respond.

That gives you a better read on:

• analytical discipline
• clarity under pressure
• ability to make concessions without losing the core opinion

10. If this case goes to trial, are you the expert we want?

This is the final question, and in many ways the most important.

Guo’s warning is practical: “It’s never just a preliminary review” if the case continues. If you may need testimony later, vet for that now. Otherwise, you risk paying for the same review twice and rebuilding your expert strategy midstream.

That is why expert search should be trial-minded from the start. The strongest retention decisions account for admissibility, logistics, conflicts, and credibility before the engagement letter is signed.

A careful upfront interview will not eliminate every risk. But it will surface the avoidable ones early, when you still have options.