The Volokh Conspiracy

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Federal Judges Continue to Ignore the Plain Text of Federal Rule of Evidence 702

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On December 7, Eugene reported:

From retired Third Circuit Judge Thomas Vanaskie (who had also served on the Middle District of Pennsylvania), and who was serving as a court-appointed Special Master in In re: Valsartan Losartan, and Irbesartan Products Liability Litigation; the decision was handed down Sept. 3, but just came up on one of my searches:

Dr. Sawyer's citation to non-existent sources due to his use of an artificial intelligence tool without adequate verification of the sources generated by the artificial intelligence tool, while perhaps warranting an award of costs in favor the defense and permitting cross examination of Dr. Sawyer during the trial on his failure to verify the sources cited in his report, does not warrant exclusion of his opinions as they are otherwise the product of reliable scientific methodology and are supported by "good grounds," especially given "the liberal thrust of the Federal Rules of Evidence, the flexible nature of the Daubert inquiry, and the proper roles of the judge and jury in evaluating the ultimate credibility of an expert's opinion" ….

The quotation about the liberal thrust, flexible nature, etc, of the Daubert inquiry is taken from Heller v. Shaw Industries, Inc., 167 F.3d 146, 155 (3d Cir. 1999).

I don't have any particular opinion about what judges should do about AI hallucinations in expert reports, but I do want to express my continued frustration about judges (or in this case a retired judge serving as a special master) simply ignoring the text of Federal Rule of Evidence 702.

To make a long story short, the Heller quotation was of dubious merit in 1999, but quoting it in 2025 neglects the fact that while the Daubert case interpreted Rule 702 as it existed in 1993, since 1999 there have been two (count 'em, two) amendments to Rule 702. As a result, we know longer properly have "a Daubert inquiry," with whatever ambiguities or bows to the alleged liberality of the rules the case supplied, but a federal rule of evidence amended twice, in 2000 and again in 2023. Here is the rule:
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 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.

Note that the rule does not say anything about the test being flexible, liberal, or deferential to the jury. Indeed, the 2023 amendment added "demonstrates to the court" precisely to dissuade judges from believing that they can and should pass off the reliability issues to the jury under Rule 104(b) rather than making an initial judicial determination of admissibility under Rule 104(a).

Rule 702 as amended, not Daubert, not circuit precedent relying on Daubert, is the law of the land, and it's time for judges to start acting that way.