Challenges to Expert Witnesses Under New Rule of Evidence 702

Experts on Notice

Federal Rule of Evidence 702 has undergone changes; these were made in 2000 and 2011. The recent amendments clarify the gatekeeping function of the trial court. A trial court is charged not with weighing the expert’s opinion; rather it is charged with determining if the testimony is admissible. This article discusses the recent changes to this rule and how this will impact proposed experts and their counsel’s choice of experts.

Ever since the United States Supreme Court rendered its groundbreaking decision in 1993 in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993), expert witnesses have faced challenges to their ability to offer expert testimony at trial. The Daubert decision used the language of Federal Rule of Evidence (FRE) 702 to impose a gatekeeping function on trial judges, who are now expected to keep junk science out of their courtrooms. Specifically, a trial judge “must determine at the outset … whether the expert is proposing to testify to (1) scientific knowledge that (2) will assist the trier of fact to understand or determine a fact in issue.” As the Supreme Court put it, “[t]his entails a preliminary assessment of whether the reasoning or methodology underlying the testimony is scientifically valid and of whether that reasoning or methodology properly can be applied to the facts at issue.” And thus, the Daubert test was created.

The Daubert test replaced the longstanding requirement from Frye v. United States, 293 F. 1013 (D.C. Cir. 1923), that an expert opinion “must be sufficiently established to have gained general acceptance in the particular field in which it belongs.” The Supreme Court’s decision to replace the Frye general-acceptance test flowed from the language of FRE 702, which stated at that time:

If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise.

The Daubert decision’s interpretation of that language prescribed the standards for the admission of expert testimony for three decades, as the lower courts did their best to faithfully apply the test set forth in Daubert.

With the passage of time, cracks in the foundation of the Daubert test started to appear. The most significant erosion of Daubert came in the gatekeeping function assigned to the trial courts. Although Daubert suggested a robust screening process prior to trial, trial courts routinely denied Daubert motions to exclude expert testimony, finding that the challenges to the proposed expert testimony merely bore upon the weight, as opposed to the admissibility, of the expert testimony. Accordingly, trial courts commonly concluded that juries should determine the weight to be assigned to the expert testimony, which would be admitted at trial for consideration just like any other evidence. That approach seemed inconsistent with the Supreme Court’s view in Daubert “that, in practice, a gatekeeping role for the judge, no matter how flexible, inevitably on occasion will prevent the jury from learning of authentic insights and innovations.”

Amendments to FRE 702 made in 2000 and 2011 failed to quell the concerns about the way the rule was being applied by trial judges. So, in December 2023, a new version of FRE 702 went into effect to clarify how trial courts should exercise their gatekeeping responsibilities. That version of FRE 702 states as follows:

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 the proponent demonstrates to the court that it is more likely than not that:

(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’s opinion reflects a reliable application of the principles and methods to the facts of the case.

The notes of the advisory committee that drafted the amendment explain that “many courts have held that the critical questions of the sufficiency of an expert’s basis, and the application of the expert’s methodology, are questions of weight and not admissibility.” According to the advisory committee, “[t]hese rulings are an incorrect application of Rules 702 and 104(a)” of the FRE.

To rectify the flawed approach to the gatekeeping responsibility employed by trial courts, the advisory committee made two amendments to FRE 702. First, FRE 702 was “amended to clarify and emphasize that expert testimony may not be admitted unless the proponent demonstrates to the court that it is more likely than not that the proffered testimony meets the admissibility requirements set forth in the evidence rules.” This standard requires the proponent of the expert testimony to convince the trial court by a preponderance of the evidence that the proposed expert testimony meets the requirements of FRE 702. Second, FRE 702 was “also amended to emphasize that each expert opinion must stay within the bounds of what can be concluded from the reliable application of the expert’s basis and methodology.” In that respect, diligent gatekeeping by trial courts “is essential because just as jurors may be unable, due to lack of specialized knowledge, to evaluate meaningfully the reliability of scientific and other methods underlying expert opinion, jurors may also lack the specialized knowledge to determine whether the conclusions of an expert go beyond what the expert’s basis and methodology may reliably support.”

So, what do these recent amendments to FRE 702 portend for expert witnesses? The advisory committee notes promise that nothing in the amendments obligates trial courts “to nitpick an expert’s opinion in order to reach a perfect expression of what the basis and methodology can support.” But the amendments almost certainly will require expert witnesses to undergo more intense Daubert hearings where their credentials and opinions will be scrutinized. Beyond that, expert witnesses must be prepared not only to identify and defend their credentials and opinions, but also to explain in clear terms their forensic testimony. The advisory committee observed that the amendments to FRE 702 are “especially pertinent to the testimony of forensic experts in both civil and criminal cases” and offered the following guidance: “Forensic experts should avoid assertions of absolute or 100 percent certainty—or to a reasonable degree of scientific certainty—if the methodology is subjective and thus potentially subject to error.”

The propensity of trial courts to treat challenges to expert witnesses as contests about the weight, rather than the admissibility, of expert opinions may turn out to be a hard habit for trial courts to break. But if trial courts seriously embrace the rationale supporting the amendments to FRE 702, expert witnesses can expect more scrutiny of their expert opinions. Given the serious adverse consequences that result from disqualification of a proposed expert witness after a Daubert hearing, experts should take very seriously their preparation—and the preparation of their retaining counsel—before each Daubert hearing no matter how meritless the challenge may seem.

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Hon. Christopher Yates serves as an appeals court at the 3^rd District of the Michigan Court of Appeals. Judge Yates is a former assistant U.S. attorney for the Eastern District of Michigan and federal public defender for the Western District. He was the chief federal public defender prior to becoming a private practice lawyer in 2004. He first served with the firm of Willey, Chamberlain & Yates and later became a partner in the firm of Yates, LaGrand & Denenfeld. He was appointed to the circuit court in 2008. He has also taught at the Michigan State University School of Law and Davenport University.

Judge Yates may be contacted at (616) 456-1167 or by e-mail to CYates@courts.mi.gov.