Amended Federal Rule of Evidence 702: What You Need To Know About the Admissibility of Expert Testimony

Effective today, Federal Rule of Evidence 702 (Rule 702) has been amended to clarify how trial judges, as gatekeepers, should decide the admissibility of expert testimony. According to the Advisory Committee on Evidence Rules (Advisory Committee), the amendments address common misinterpretations and misapplications of Rule 702 by trial courts.

Judicial Gatekeeping of Expert Testimony

Under Rule 702, federal judges have traditionally enjoyed broad discretion as gatekeepers of expert testimony. But according to the Fourth Circuit, some courts had “abdicate[d] that duty by opening the gate indiscriminately to any proffered expert witness” and “exposing jurors to ‘dubious scientific testimony’ that [could] ultimately ‘sway[]’ their verdict.”¹

Prompted by trial courts’ common misapplication of Rule 702, the Advisory Committee amended the rule as follows:

Rule 702. Testimony by Expert Witness

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 has reliably applied expert’s opinion reflects a reliable application of the principles and methods to the facts of the case.

First, the amended Rule clarifies that the party offering expert opinions must prove admissibility by a preponderance of the evidence. Previously, citing a “liberal standard of admissibility,” many courts wrongly presumed that questions about the sufficiency of the expert’s basis or methodology went to the weight of the evidence, not its admissibility. The Advisory Committee made clear that “[t]hese rulings are an incorrect application of Rules 702 and 104(a).”²

Second, the amended Rule clarifies and emphasizes that “each expert opinion must stay within the bounds of what can be concluded from a reliable application of the expert’s basis and methodology.”³ As the Advisory Committee explained, the explicit reference to the “expert’s opinion” invites a trial court to give more direct scrutiny to an expert’s ultimate conclusions, not just the underlying principles and methods employed.⁴

Takeaways: Back to the Future

Amended Rule 702 takes effect on December 1. It applies to new cases and all pending cases “insofar as just and practicable.”⁵ We expect the Rule’s application to pending cases to be relatively pain-free, because the amendments are meant to clarify how Rule 702 should have been interpreted and applied all along.⁶ Moreover, over the last few years, courts have already started to apply the Advisory Committee’s remarks to align their analyses under Rule 702.⁷

Litigants who are briefing motions to exclude expert testimony (or where a court has recently decided such a motion) should look closely for any reliance on propositions of law with which the Advisory Committee took issue. Depending on the circumstances, one or both parties may want to seek clarification or reconsideration to preserve the issue for appeal.

These amendments should result in more expert opinions being excluded. Litigants are likely to be more bullish in challenging an expert’s ultimate opinions, especially under Rule 702(b) and (d). Likewise, trial courts will find it more difficult to categorically brush aside these challenges as nothing more than fodder for cross-examination. That said, the Advisory Committee made clear in its comments that not every challenge to an expert’s opinion must go to admissibility: “[O]nce the court has found it more likely than not that the admissibility requirement has been met, any attack by the opponent will go only to the weight of the evidence.”⁸ This offers a glimpse into how judges might recast their conclusions by focusing on whether the threshold burden has been met, then setting aside further challenges for the jury to weigh at trial.

For more information regarding the admissibility of expert testimony, please contact any of the authors or your primary Arnold & Porter attorney.

© Arnold & Porter Kaye Scholer LLP 2023 All Rights Reserved. This Advisory is intended to be a general summary of the law and does not constitute legal advice. You should consult with counsel to determine applicable legal requirements in a specific fact situation.