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Best Practices When Preparing To Cross-Examine Expert Witnesses

Christine Funk

Written by
— Updated on December 8, 2021

Best Practices When Preparing To Cross-Examine Expert Witnesses

Cross examination of an expert can feel like a daunting task. Not only are you asking direct, pointed questions, sometimes specifically designed to discredit or call into question a witness’ opinion, you are doing so to someone who’s expertise in a given area far exceeds your own. Even with a month of undivided preparation time, your knowledge and skill on the issue at hand will not rival their Ph.D. in the subject. So what is an attorney to do?

Prepare, Prepare, Prepare

Having your own expert to consult and discuss issues with is a huge benefit. However, you will still have to cross examine the other expert on your own. As the lawyer, it is up to you to evaluate strategy, develop themes, and present the case. In preparation for your cross examination, nothing helps an attorney prepare like a chat with the other side’s expert. The approach to the meeting, and the follow up from the meeting, will vary depending on a number of circumstances, including state rules and local practice. For example, while depositions are common place in criminal cases in Florida, they are almost unheard of in Minnesota.

At the meeting or deposition, an attorney has the opportunity to assess the basis for the expert’s opinion. Attorneys are encouraged to push the basis of knowledge offered. If an expert claims, “There are studies to support this,” push to identify which studies. Then take the next step and obtain those studies and review them for accuracy. Do they actually say what the expert claimed they said? Are there caveats the expert did not consider?

Attorneys should carefully consider their approach to a pretrial meeting. Confrontation and cross examination may not be the best approaches. Asking open ended questions in a pretrial meeting gives the attorney to assess how the expert might testify on direct. It also gives the expert the opportunity to talk at length, and provide information about the basis for their opinion beyond what may be considered in cross examination questions. This gives the attorney a better idea of how to prepare for cross examination at trial.

Know the Facts

One area where an attorney can excel is in making certain they have a better grasp on the facts of the case than the expert. Expert opinions are based on facts that are case specific. Whether or not CPR was administered to a child by an untrained but very strong man can impact the assessment of when or how the child’s ribs were broken. Whether the kitchen contained a slow cooker with a faulty electrical cord may impact the potential for an accidental fire. The expert’s opinion is limited by the facts as known to the expert. Make certain any comparisons are fair ones.

  • Q. You indicated on direct that there was support for your position in the literature.
  • A. That’s right.
  • Q. You cited Exhibit 12 as supporting your proposition that a child could be shaken so hard a vertebrae in their spinal column could break.
  • A. That’s right.
  • Q. The research paper that you cited, it wasn’t specifically about broken vertebrae in shaken infants, was it?
  • A. No, it was about child abuse in general.
  • Q. And in fact, the article specifically cited one instance of this happening.
  • A. Yes. So it has happened.
  • Q. But that child was 9 weeks old.
  • A. I’m not really sure how old the child was.
  • Q. I can show you the Exhibit if you’d like.
  • A. Yes. 9 weeks old.
  • Q. The child in this case was 13 months old.
  • A. Okay.
  • Q. The child referenced in the Exhibit weighed just over 10 pounds.
  • A. That’s right.
  • Q. But the child in this case weighed 26 pounds.
  • A. 26.2, I believe.

Follow Up

In states and cases where depositions take place, it makes sense to ask the witness to review their testimony and correct any errors. In cases where the meeting is not recorded, it makes good sense to send a letter after the meeting, summarizing your understanding of what was said. The letter should also ask that any misstatements be corrected. You can’t make the expert respond, of course. However, a skilled litigator can use any response – or the choice not to respond – in trial if the need arises.

Dear Dr. Jones,

Thank you for taking the time to meet with me in your office on December 23, 2017. I appreciated the opportunity to speak with you about the case. As a reminder, you indicated you would locate those studies supporting your position that the flu vaccination regularly causes an allergic reaction in 10 % of the population.
Additionally, I want to confirm my understanding of what you said about the reaction my client suffered. As I understand your statements, the reaction was a result of her allergies, not a problem with the vaccination itself. Can you confirm this is a correct recitation of your position?
Many thanks.


With this sort of documentation, an attorney can pursue one of two approaches at trial, should the witness testify in a way that is unexpected.

  • Q. Dr., didn’t you and I meet in December of last year to discuss this case?
  • A. Yes.
  • Q. And didn’t I send you a letter asking you about my client’s reaction?
  • A. Yes.
  • Q. And you did, in fact, confirm the facts as I recited them in my letter?
  • OR
  • Q. And you didn’t respond to my request, did you?

In either event, the witness’ credibility is called into question.

Research and Review Best Practices

In many cases, your own expert can assist in directing you to best practices for the field. If a discipline involves science, it is reasonable to expect there are standards that guide scientists on how to approach an issue. By reviewing an opposing expert’s work, and questioning them ahead of time about how they approached the problem, a line of cross examination may present itself to an attorney who knows how the work is supposed to be performed in the field.

  • Q. Are you familiar with the National Fire Protection Association?
  • A. Of course.
  • Q. Are you aware the NFPA puts out publications discussing best practices?
  • A. Yes.
  • Q. Are you familiar with NFPA 1033, which discusses a fire investigator’s professional qualifications?
  • A. Yes.
  • Q. Are you familiar with NFPA 1033 requirement 4.1.2, which calls for fire investigators to “employ all elements of the scientific method as the operating analytical process throughout the investigation and for the drawing of conclusions?”
  • A. Yes.
  • Q. But you didn’t do that in this case, did you?
  • A. I most certainly did.
  • Q. Are you familiar with NFPA 921?
  • A. Yes.
  • Q. Are you familiar with the steps listed for employing the scientific method?
  • A. Of course.
  • Q. It includes collecting data?
  • A. Yes.
  • Q. Analyzing data?
  • A. I did that.
  • Q. Developing a hypothesis?
  • A. Yes.
  • Q. And testing the hypothesis?
  • A. I couldn’t test the hypothesis. I put that in my report.
  • Q. Are you aware of NFPA 921, which states, “Any hypothesis that is incapable of being tested either physically or analytically is an invalid hypotheses?”

Check Their Work

You don’t need to know a lot about closed head injuries to know that if a doctor says an infant’s head injury is similar to that of a car crash at 55 miles an hour, this at least suggests he’s seen an infant head injury from a car crash at 55 miles an hour. Take a look at the expert’s CV and pull some statistics. Do you know how many infants died in car crashes in 2015 in your state? What about the ten years before that? Is there more than one medical examiner in your state? More than one medical examiner in the office? When experts make claims about their experience, they should be able to back it up with data to support their claims.

  • Q. Doctor, as I understand it, 0 children under one year of age were killed in traffic fatalities in 2015 in Colorado.
  • A. I’m not sure where you are getting your data.
  • Q. The National Highway Transportation Safety Associate reports that, in addition to zero infant deaths in traffic fatalities in 2015, there were zero infant deaths associated with traffic fatalities in 2014 in Colorado as well.
  • A. As I said, I’m not sure where you are getting your data.
  • Q. Is it your testimony that you have examined an infant who died as the result of a traffic fatality in 2015?
  • A. No.
  • Q. 2014?
  • A. No.
  • Q. You testified on direct the injuries this infant sustained were the same as if they had been in a car crash when the car was traveling 55 mph. What, exactly do you base this opinion on, if you haven’t actually autopsied any children in the same age range under those circumstances?
  • A. My training and experience, of course.
  • Q. What experience, exactly?
  • A. I did my residency in North Dakota.
  • Q. How many infant deaths associated with traffic accidents did you see there? Should we look it up?

Of course, this approach only works if one has researched the data and has it readily available during the trial.

Prepping for Cross Exam

In every case involving expert testimony, one cannot discount the need for preparation. Preparation includes meeting with the opposing expert and identifying areas of attack, from the scientific basis for the expert’s conclusions, to best practices, to relevant studies in the field, to hands on experience.

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