Opposing counsel usually attacks an expert witness in predictable ways. The questions are rarely surprising. What matters is whether your team has already pressure-tested the answers.
Most challenges fall into a few familiar categories: qualifications, scope, methodology, bias, prior testimony, and discoverable materials. If one of those areas is weak, a deposition can expose it quickly. If the weakness is serious enough, it can affect admissibility, settlement posture, and trial presentation.
1. “What qualifies you to offer this opinion?”
This is the first gatekeeping question, and often the most important.
Expect scrutiny on:
- licensure and board certification
- subspecialty training
- current practice area
- experience with the exact issue in dispute
- whether the expert is stretching beyond their actual discipline
That distinction matters. A physician may be highly credentialed and still be vulnerable if the opinion reaches into a specialty they do not actually practice. In one deposition reviewed during Expert Institute’s internal analysis, a neonatologist pushed back hard on being characterized as an obstetrician and made clear he would not offer delivery-related standard-of-care opinions.
Preparation point: make sure the expert can clearly define what they will say, and just as clearly what they will not.
2. “Have you testified before, and has any court limited or excluded you?”
Opposing counsel asks this to test credibility and to build a record for a later challenge.
They may ask:
- how many times the expert has testified
- whether those matters were in state or federal court
- whether testimony was by deposition, trial, or affidavit
- whether any opinions were excluded, limited, or challenged
This is also where self-reporting can break down. Experts do not always remember prior matters accurately, and some may not understand whether a prior ruling counts as a Daubert-type exclusion or other limitation.
Preparation point: do not rely solely on the expert’s memory. Verify prior testimony and prior challenges independently.
3. “Is your CV current and complete?”
A stale CV creates avoidable risk.
If publications, appointments, certifications, or licenses are missing, opposing counsel may be the first to surface them. Worse, they may find a recent article, presentation, or online statement that cuts against the opinion in the case.
Preparation point: confirm that the CV is fully current before disclosure. That includes publications, speaking engagements, licenses, hospital affiliations, and board certification status.
4. “Have you ever had a license issue, disciplinary action, or other professional blemish?”
This line of attack is not limited to formal discipline. It may include:
- suspended or lapsed licenses
- board certification problems
- hospital privilege issues
- prior lawsuits related to similar conduct
- arrests, financial trouble, or other credibility concerns
Not every issue is disqualifying. But if opposing counsel finds it first, the expert can look evasive even when the underlying fact is explainable.
Preparation point: run the search before the other side does.
5. “What materials did you review, and what did you ignore?”
This question goes to both reliability and preparedness.
Expect detailed follow-up on:
- records reviewed
- deposition transcripts
- codes, standards, or guidelines
- imaging, testing, or device materials
- documents not reviewed and why
A common problem is the expert who repeatedly says, “I don’t recall,” because the relevant material is not fresh. That hurts credibility fast.
Preparation point: the expert should re-review the core materials they cite and be able to explain why certain sources mattered more than others.
6. “Did you rely on another expert’s opinions?”
This can become a serious vulnerability.
If your expert leans too heavily on another retained expert, and that other expert is later excluded, the damage can spread. An opinion that cannot stand on its own factual foundation is easier to attack.
Preparation point: make sure the expert can identify the independent basis for each key conclusion.
7. “Are you actually active in the field?”
For medical experts especially, opposing counsel will test whether the witness is a practicing professional or primarily a litigation witness.
Typical questions include:
- What percentage of your work is clinical?
- Were you practicing at the time of the incident?
- In what setting do you work?
- How often do you see this condition, procedure, or device?
This can also matter for jurisdiction-specific fit, especially where similar practice setting is important.
Preparation point: connect the expert’s day-to-day work to the facts of the case as specifically as possible.
8. “How much of your income comes from expert work?”
This is the classic “hired gun” line of attack.
Expect questions about:
- hourly rates
- review, deposition, and trial fees
- plaintiff/defense split
- percentage of income from forensic work
- prior work with the same attorney or firm
High compensation alone is not fatal. What matters is whether the expert can answer these questions directly and without defensiveness.
Preparation point: know the fee schedule, know the prior relationship history, and prepare for the professional witness narrative.
9. “What have you written or said on this issue before?”
Publications, blog posts, lectures, interviews, and prior testimony are all fair targets.
Opposing counsel is looking for inconsistency: a prior article, presentation, or transcript that appears to conflict with the current opinion.
Preparation point: review the expert’s public and litigation history on the exact issue in dispute, not just the general subject area.
10. “Can you stay composed when challenged?”
This is not always asked directly, but it is tested throughout the deposition.
Some experts have strong credentials and sound opinions, yet perform poorly under pressure. They become argumentative, overstate answers, or volunteer beyond the question. That can do real damage with both judges and juries.
Preparation point: vet for temperament, not just expertise. A credible expert must be able to hold the line without losing composure.
The practical takeaway
Most expert attacks are foreseeable. The real question is whether they are discovered early enough to address.
That is why expert preparation starts with vetting, not with the deposition outline. A disciplined review of qualifications, prior testimony, publications, compensation history, and potential credibility issues can prevent avoidable surprises. For teams that need a clearer record before disclosure or deposition, services like Expert Radar can help surface those issues before opposing counsel does.
