Juries and Expert Witnesses: A Balanced or Toxic Relationship?

 As with any legal inquiry, the answer is: it depends.

Federal Rules of Evidence: Rule 702

Rule 702 states that an expert witness's testimony is admissible if: 

"A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if:

(a) the expert's scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue;

(b) the testimony is based on sufficient facts or data;

(c) the testimony is the product of reliable principles and methods; and

(d) the expert has reliably applied the principles and methods to the facts of the case."

Fed. R. Evid. 702

In 1993, the Supreme Court in Daubert created a non-exhaustive list of factors to consider when evaluating expert testimony admissibility. Later, Rule 702 was amended to the current version shown above to broad factors that include those enumerated by the Supreme Court. As common practice, "exclusion of expert testimony is the exception rather than the rule." 

Juries and Expert Witness Testimony

Why even bother with expert witness testimony if it is ultimately up to the jury to act as the factfinder and determine liability? As mentioned in a variety of case studies, some cases involve very technical issues that do not arise in daily lives of common people. Some cases need a medical expert to describe a victim's injuries and/or how those injuries may occur. Other cases need a business expert to describe what all the numbers mean and how they relate to each other to show a mismanagement of funds. However, when an expert is needed to further explain a complex issue, expert witness testimony is one of many forms of evidence lawyers should rely on. At the end of trial, it is still up to the jury to decide whether the testimony is credible and reliable or if other evidence was presented to overcome the expert's opinion. 

A juror's task is to evaluate all the facts and testimony presented at trial without bias and in a fair manner. But what if the expert is using highly technical terms and does not break it down into digestible pieces for the jury? Then, the expert's testimony is usually lost on the jury, and the jury is less likely to rely on that expert's testimony. It is important for lawyers to practice with their expert witnesses to present an engaging, understandable story with unambiguous language.

However, there is a power struggle between an expert and a layperson on a jury. Sometimes jurors defer to experts because they are clearly more knowledgeable in the subject matter. With that being said, in a simulated situation, jurors valued an expert's high expertise and extensive time researching and practicing in their field of expertise. But a survey showed that the jurors did not let the expert's expertise sway their final verdict. They considered all evidence presented, as they should, before deciding on their final verdict.

After many case studies on this issue, there are three main takeaways. First, it is vital for lawyers to prep their expert witnesses to tell an engaging story that the jury will be able to understand instantly. Second, a judge has discretion under the Federal Rules and caselaw on whether to admit the expert's testimony. And third, proper display and organization of other evidence in addition to expert testimony will encourage juries in their fact-finding capabilities on reaching a fair and just verdict.

It is up to judges and lawyers to make sure there is a balanced relationship between juries and expert witnesses.