The usefulness of any witness depends largely on his or her credibility with the jury.  This is especially true for expert witnesses whose testimony is often pitted against that of an opposing counsel’s expert. In these instances, each expert’s credibility may determine which of their contradicting conclusions jurors choose to adopt. It’s therefore perfectly reasonable that our clients sometimes ask, “Will my expert appear biased?”

First of all, jurors tend to be skeptical of any paid expert and, many times, if there are paid experts on both sides, jurors have told us they “canceled each other out.” Why? Jurors tell us that because a witness has been paid by a party, he appears to have a dog in the fight. In our post-trial interviews, jurors often say they “just wanted to hear from an independent expert.” In our adversarial judicial system, we all know that is just wishful thinking. While you may never be able to undo the stigma of hanging your case on witnesses who are being paid to be there, there are ways of presenting an expert witness so that she appears less biased than her counterpart.

Indeed, jurors don’t perceive all experts as “hired guns.” Our experience interviewing jurors post-trial shows that many paid experts are taken seriously, and their opinions can hold important weight with the jury.  So, what factors cause an expert to lose credibility with a group of jurors? Although there are many genres of experts, the following findings applies to most – if not all – experts who are likely to testify on behalf of your client at trial.

Factors that Influence an Expert’s Credibility

  • How much does your expert get paid? Be mindful of how much the vast majority of jurors actually make for a living – or worse, how much they are being paid for their jury service. Many jurors are hard-working folks who earn hourly wages or modest salaries, especially when compared to your experts. When jurors hear that an expert is making $7,500 for their time to testify on that single day, that amount may equate to two or three month’s salary for your jurors.  Jurors may surmise that, at such a rate, your expert would say anything to help your client. One common tactic for minimizing this effect is to emphasize that the witness is being paid “for their time” as opposed to “for their testimony.”  Your jury consultant may be able to suggest other ways to curtail the inherent bias that jurors are likely to perceive as a result of your witness’s hefty pay day.
  • For whom does the expert testify? Another factor that makes jurors cringe is when they hear that an expert has only ever testified for one side or the other. The more a witness can show a mixed resume, the better. If a witness has testified for both plaintiffs and defendants in cases – even in different genres of litigation – he is less likely to come across as a zealot or as an expert on your payroll.  While this is often unavoidable when an expert’s findings or opinions always favor one side’s point of view, there are ways of conveying this caveat to the jury.  For example, if true, the expert may want to explain that he will testify on behalf of any party who chooses to retain him, but, as of yet, he has never been approached by a plaintiff’s attorney (or even better, he has furnished reports or opinions to plaintiffs and they have rejected his offer to testify at trial).

It is always especially helpful to point out when an expert’s research and publications pre-date his experiences as an expert witness, an indication that the expert’s findings were motivated by science, medicine, etc., as opposed to litigation. In instances where an expert is providing an opinion with regard to a particular plaintiff’s situation, it may be helpful to show that the expert furnished an independent evaluation of the case before agreeing to testify on behalf of your client and, if true, that she has rendered unfavorable opinions for your side on past cases, adding credence to her testimony in this case.

  • How arrogant is your expert? An arrogant witness may project an impression that he is inconvenienced by having to testify, that he feels superior to the jurors and others in the courtroom and that the case cannot be won without his testimony. These kinds of witnesses are often not self-aware, insensitive to how they are perceived by others. They tend either to talk down to the jury or forget their audience altogether and lecture as if they were speaking to their colleagues or graduate students.  As a result, an arrogant witness fails to connect with a jury, and jurors are less likely to believe that an arrogant expert has approached the research and evidence with an open mind or evaluated the case fairly to arrive at his conclusions.  All of these factors combine to make an incredible witness.  Although a pompous witness may be resistant to witness preparation with a jury consultant, an effective preparation can help him relate his wealth of knowledge to the jurors through thematic storytelling and engaging teaching techniques.  Rather than submerging in technical or scientific details that are likely to alienate the jury, an effective – and credible – expert can simplify the science and become a humble teacher that your jury comes to trust.


Until expert witnesses begin offering their testimony for free, or begin to charge modest rates for their time (i.e., when pigs fly), attorneys will have to deal with the fact that jurors are predisposed to perceive their experts as biased. Nevertheless, there are a number of ways to minimize this perception so that the question is not whether your witness will appear biased, but whether she will appear less biased than your opponent’s experts, and whether your witness can appear credible despite these biases.  Preparation for both the examining attorney and the witness with a jury consultant who is experienced in working with experts is likely to address many of these concerns and develop methods for improving your witnesses’ credibility.

About the Author

Dr. Pitera presented this paper at the SEAK National Expert Witness Conference April 27-28, 2019 in Clearwater Beach, Florida.