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How to cross-examine an expert witness

The purpose of cross-examination is to continue to argue — and defend — your case by using leading questions to obtain affirmative answers.

The leading question with the desired answer is the key to effective cross-examination of all witnesses, including the expert. It allows you to control the witness and obtain the desired answer most of the time.

For example: “Doctor, you provided a report containing the opinions you would offer during trial?”  “Yes.” “You agree the opinion you just offered about the role of chest pain in diagnosing Mrs. Brown’s condition is not in your report?” “Yes.”

Bear in mind that before the expert testifies on direct examination and is cross-examined, you will have had the opportunity, prior to trial, to challenge the admissibility of all expert testimony in a so-called “Daubert hearing.” You will also have had the opportunity to voir dire (question)  the expert, based on his or her qualifications, after opposing counsel qualifies the expert and requests the court to accept the witness as an expert.

Consider the following four goals the next time you are prepping for cross-examination:

1. Use the adverse expert to develop your own case independently (known as hitchhiking). Show the jury that your expert is credible. For example: “Dr. Smith, you know our expert witness in this case, Dr. Jones?” “Yes.” “You took her class on infectious diseases while you were in medical school?” “Yes.” “She was a great teacher?” “Yes.”

If the witness answered “no” to any question, you might politely refresh their recollection without impeaching them.  For example: “Doctor, you recall writing an article praising Dr. Jones while you were a student in medical school?”  “As a matter of fact I do.” Remember, cross-examination of a witness does not always involve impeachment.

2. Reveal discrepancies between direct examination and facts. Assume during direct an adverse witness testifies that Mrs. Brown did not complain about chest pain in the ER.

Cross-examination of the defense expert might then look something like this:

“Dr. Smith, you agree that the date of Mrs. Brown’s hospital visit was March 22, 2022?”  “Yes.”  “You agree that on that date she did complain of chest pain?” “Yes” “The date of this visit of March 22, 2022 and her complaint are reflected in the hospital records, Plaintiff’s Exhibit 7,  correct?”  “Yes.”

3. Use the testimony of the adverse expert to corroborate the favorable testimony of other witnesses. For example: “Dr. Smith, you were in court when Dr. Jones, our expert, testified that one symptom of a dissected aorta is chest pain?” “Yes.” “You testified in your deposition that you agree with that?” “Yes.”

4. Use impeachment to discredit the witness’s testimony or the witness. Once a witness testifies contrary to a prior statement, you have the basis to impeach. Commit the witness to their present trial testimony, give reference to the statement before trial, and then confront the witness with the prior writing or statement.

For example: “Dr. Smith, you just testified that you base your opinion that Dr. North was not negligent in misdiagnosing Mrs. Brown’s condition on the fact that she did not complain in the emergency room about chest pain?” “Yes.” “But did she not mention chest pain to one of the nurses in the emergency room?”  “No.” “Let me show you page two, second paragraph, of the emergency room records marked as Plaintiff’s Exhibit 8.  Please read to us paragraph two.” (The witness reads to the jury that the plaintiff did complain to the nurse about experiencing chest pain.)

In preparation for the cross-examination, study the expert’s reports, and review them with your expert. Try to obtain the history of the expert’s trial testimony, and, if available, transcripts of prior testimony. Also review your expert’s basis for disagreement with the adverse expert.

Remember that unlike in federal court, there exists no confidentiality in state court, making even draft reports by the expert discoverable. One approach I have taken in state court proceedings is to form a handshake agreement with all counsel to adopt federal court rules for expert discovery in state litigation.

Here are some final points to consider:

  • Select only topics that are advantageous to your case, and arrange them strategically.
  • Remember your theme and organize around it. Do not wander in your questioning, and know when to sit down.
  • Conduct cross-examination with a delivery and style that is consistent with your specific goals and sense of propriety.

Of course, there is much more to mastering the skill of effective cross-examination of experts  than discussed here. I urge you to read more about it. Also, consider listening to the MSBA’s “Six-Minute Audio Skills Series,” which includes these tips and other topics. Remember: According to Wigmore, cross-examination is the greatest legal engine for the truth that was ever invented.

Paul Mark Sandler, trial lawyer and author, can be reached at pms@shapirosher.com.