I don't think we ever did a post on this, but back in 2023, Federal Rule of Evidence 702 was amended to clarify that the burden of showing admissibility of an expert witness's testimony falls on the offering party (addition highlighted below):
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 . . .
FRE 702 (2025).
T his is consistent with a long-standing Third Circuit holding in In re Paoli R.R. …
