Since 2000, Rule 702 has laid out the requirements for the admissibility of expert witness testimony and the assessments courts must make to determine whether a jury will hear an expert’s testimony. A significant amendment to Federal Rule of Evidence 702 will take effect on December 1, 2023. The amendment makes no substantive change but reiterates how judges must act as gatekeepers regarding admissibility of expert testimony.
To “clarify and emphasize” the admissibility requirements, the amendment changes the language of Rule 702 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 new language explicitly dictates that the burden of proof in Rule 702 is a preponderance of the evidence and affirms that the expert’s opinion must reflect a reliable application of the expert’s principles and methods. This phrase replaces the language that the “expert [must] ha[ve] reliably applied” the expert’s principles and methods, emphasizing that the opinion itself must reflect the reliable application of the expert’s principles and methods. The Advisory Committee recommended this amendment because courts have been ignoring these critical elements. Many federal decisions incorrectly articulate and fail to properly apply the Rule 702 gatekeeping standard.
The Advisory Committee clarified that “critical questions of the sufficiency of an expert’s basis, and the application of the expert’s methodology” are questions of admissibility, not weight: “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 generally questions of weight and not admissibility. These rulings are an incorrect application of Rules 702 and 104(a).” Appendix to Report of the Advisory Committee on Evidence Rules (May 15, 2021), in COMMITTEE ON RULES OF PRACTICE AND PROCEDURE AGENDA BOOK June 22, 2021 AGENDA BOOK 836 (2021).
The Committee also made clear that the proponent must demonstrate to the court that it is “more likely than not” that the expert’s testimony meets Rule 702’s admissibility requirements. Fed. R. Evid. 702 advisory committee note to 2023 amendment. This emphasis on the preponderance standard “was made necessary by the courts that have failed to apply correctly the reliability requirements” of the rule. Id.