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Ensuring Intellectual Rigor: Three Reasons for Amending the Expert Admissibility Standard

Anais Mitra, Jody Marie Rhodes, and Christopher Grey Campbell


  • Proposed amendments to Federal Rule of Evidence 702 clarify that the proponent of expert testimony must demonstrate its reliability and admissibility by a preponderance of the evidence.
  • The amendments underscore the judge’s responsibility to ensure the expert’s opinion is reliably applied to the case facts, preventing the misapprehension that reliability is merely a question for the jury.
  • These changes are crucial for mass tort cases, ensuring courts exclude unsupported and unreliable expert opinions, thus maintaining the integrity of the judicial process.
Ensuring Intellectual Rigor: Three Reasons for Amending the Expert Admissibility Standard
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Two changes to Federal Rule of Evidence 702 governing the admissibility of expert opinion are now available for public comment, the U.S. Judicial Conference’s Standing Committee on Rules of Practice and Procedure having recently voted to publish amendments to the rule. The first change introduces an explicit burden of proof as to the reliability, and thus the admissibility, of expert testimony—a preponderance of the evidence—and makes clear that the burden is on the proponent of the evidence. The second change emphasizes the judge’s gatekeeper role in determining whether the expert’s ultimate opinion is within bounds based on a reliable application of the expert’s methodology to the facts of the case. The intended effect is to clear up any lingering judicial misapprehension that the reliability of an expert’s ultimate opinion is merely a question of weight for the fact finder to decide.

The proposed amendments are particularly important in the mass tort context to ensure the courts are faithfully executing their gatekeeper function to exclude overreaching expert opinions that are unsupported and unreliable. 

The Proposed Amendments to Rule 702

The proposed amendments to Federal Rule of Evidence 702 are not intended to impose new procedures; rather, they are intended to explicitly clarify the admissibility standard within the rule’s language and emphasize the judicial gatekeeping authority established in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993).

The committee’s proposed amendments to Rule 702 are stated as follows (with added language underlined):

Rule 702. Testimony by Expert Witnesses
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 has demonstrated by a preponderance of the evidence 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 first proposed change explicitly addresses the standard under which courts must consider the admissibility of expert testimony. The admissibility of expert evidence is already governed by the Rule 104(a) preponderance of the evidence standard, as stated in the committee’s notes on the 2000 amendment; however, the proposed amendment clearly identifies the proper standard within the language of Rule 702 itself. The proposed amendment further emphasizes that the burden is on the proponent of the evidence to establish that it has, more likely than not, satisfied the admissibility factors required by Rule 702. Thus, expert testimony is permitted only where the court finds all of the rule’s factors—helpfulness to the jury, sufficient basis, reliable principles and methods, and fit to the facts—to be satisfied by a preponderance of the evidence.

The second proposed change specifically addresses the rule’s prerequisite that the expert’s opinion must fit the particular facts of the case. Amended Rule 702(d) would require the expert’s opinion itself to reflect the requisite reliable application of the underlying methodology. Further, the proposed amendment to Rule 702(d) emphasizes the trial judge’s gatekeeping role as to the ultimate opinion proffered by the testifying expert. This amendment is intended to prevent expert overreach by ensuring that expert opinions do not extend past the inferences reasonably drawn from applying the methodology and principles employed to the facts of the case.

Three Reasons Why the Proposed Amendments Are Important and Necessary

Product liability cases occupy a significant part of the civil docket, and because most of these cases require expert evidence, the discussion surrounding the reliability and admissibility of expert testimony is of the utmost importance. The committee’s proposed amendments are a necessary response to common misconceptions held by some courts regarding the admissibility standards applicable to expert opinions and are an important step to ensure that verdicts do not rely on unproven science or invalid data. These amendments clarify the intent of Rule 702, help combat improper judicial interpretation of Rule 702, and emphasize the judge’s crucial gatekeeping function.

1. Clarifying the intent of Rule 702. The intent of the 2000 amendments to Federal Rule of Evidence 702 was to establish the trial court’s role as gatekeeper and provide some “general standards that the trial court must use to assess the reliability and helpfulness of proffered expert testimony.” See Fed. R. Evid. 702 advisory committee notes to the 2000 amendments. However, it has become increasingly clear that courts are departing from the rule’s intent. The forthcoming committee notes acknowledge that “many courts have held 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,” which is an erroneously lenient application of Rules 702 and 104(a). The amendments make clear that the court plays a role in screening out ultimate expert opinions that overstate or overreach. In light of these concerns, the new amendments to Rule 702 clarify the rule’s intent and will, hopefully, lead to consistency and proper judicial application.

Especially in multidistrict litigation (MDL) cases, in which the stakes are high, misinterpretations of Rule 702 result in erroneous rulings that affect thousands of individual cases, mislead jurors, and pressure defendants to settle—implicating billions of dollars. Lawyers for Civil Justice (LCJ) recently published a report citing numerous MDL and non-MDL cases from around the country demonstrating that these courts have indeed digressed from the intended standard of Rule 702. See LCJ, Federal Courts’ Misunderstanding of Rule 702 Demonstrates Need for Amendment (2020). Hence the pressing need for an amendment that clearly prescribes the admissibility standards of expert opinion testimony under Rule 702 and emphasizes the active gatekeeping function of the judge in assessing the reliability of expert evidence.

2. Combating improper judicial applications of Rule 702. In spite of the Daubert reformation and the 2000 amendments, countless expert opinions, while flawed, have made their way into the courtrooms under the guise of sound “science.” The courts’ persistent misunderstandings of Rule 702 have led to inconsistent applications of the rule—many of which are too lenient and run contrary to the rule’s intent. Especially in recent years, misapplications of Rule 702 have become the norm as courts continue to dispense with the analytical evaluation of expert testimony contemplated by the rule.

Both the LCJ and the Washington Legal Foundation have published reports citing numerous cases misapplying Rule 702 over the past two decades. See LCJ, Federal Courts’ Misunderstanding of Rule 702 Demonstrates Need for Amendment; Lee Mickus, Gatekeeping Reorientation: Amend Rule 702 to Correct Judicial Misunderstanding about Expert Evidence (Wash. Legal Found., Critical Legal Issues Working Paper No. 217, May 2020). The erroneous precedent shows several recurring patterns of misapplication, such as presuming the admissibility of proffered testimony, disregarding the proponent’s burden of establishing admissibility, deferring to the jury questions of admissibility that are within the court’s purview, and allowing the presentation of unreliable opinions that have not been sufficiently scrutinized.

Moreover, many courts fail to understand that the factual basis and reliable application of an expert’s opinion are preliminary issues of admissibility; such issues may only proceed to the jury as credibility questions after the court has found that the proponent of the expert testimony has satisfied the burden of establishing the admissibility by a preponderance of the evidence. These departures from Rule 702’s intended rigor create confusion about the correct admissibility standard, prevent uniformity among the courts, and subject juries to the misleading influence of unreliable expert testimony. Consequently, the new amendments are necessary to remedy these misapplications—otherwise, courts will continue to assess the admissibility of expert testimony in ways that stray from the rule’s intent.

3. Restoring the court’s gatekeeping role: Precluding unreliable and unsupported opinions. Restoring the judicial gatekeeping authority is, perhaps, the most important purpose of the proposed amendments to Rule 702. While some courts have avoided their gatekeeping responsibilities by simply disregarding the requirements of Rule 702, others have pushed back with untethered reinterpretations of its provisions. Though Rule 702 directs judges to determine the reliability of an expert’s opinion, many courts continue to treat the Rule 702 reliability requirements of sufficient basis and reliable application as questions of weight and not admissibility—an approach that the committee condemns as “an incorrect application” of the rule in its forthcoming notes. Judges who rely on this erroneous approach effectively surrender judicial determinations to the jury and abdicate the gatekeeping duty conferred on them in Daubert. Consequently, the amended rule provides necessary clarification as to the courts’ role as gatekeepers who must decide the admissibility of expert testimony.

Protecting the judicial gatekeeping function is crucial to the preclusion of unreliable and unsupported opinions. Accordingly, the amendment to Rule 702(d) emphasizes the court’s gatekeeping responsibility as to the expert’s opinion itself and ensures that the expert’s opinion consists of reasonable conclusions supported by a reliable application of the methodology. In other words, the amended rule requires the judge, specifically, to assess the reliability of both the expert’s conclusions and the underlying methodology. This characterization of the factors as issues of admissibility for the judge, rather than matters of weight for the jury, is a notable safeguard of the amended rule. In this regard, the amendment is designed to prevent experts from exaggerating the reliability of their testimony (e.g., “no doubt in the slightest”); this is an important concern because jurors who might lack a basis to understand and evaluate the reliability of scientific or technical methodology will likely also lack a basis to assess an expert’s “extravagant claims that are unsupported by the expert’s basis and methodology.” See Comm. on Rules of Practice & Procedure, Agenda Book, June 22, 2021, app. at 837, Proposed Amendments to the Federal Rules of Evidence, 2021 proposed committee note. With such clarifications, the goal of preventing unsupported and unreliable assertions from making their way before the jury is all the more likely to be realized.


In sum, the proposed amendments serve to clarify the intent of Rule 702; they will also correct misinterpretations regarding the admissibility standards for evaluating expert evidence presented in the litigation setting. These changes are intended to restore consistency in judicial applications of Rule 702 across jurisdictions, emphasize the proper respective roles of the judge and the jury, and prevent the presentation of unreliable expert testimony in courtrooms. Although the new amendments will not resolve all of the evidentiary chaos prevalent in the current judicial system, it is hoped they will reorient the courts to the Daubert standard in order to ensure intellectual rigor in the courtroom.