(d) the expert has reliably applied the principles and methods to the facts of the case.
Fed. R. Evid. 702.
“It is well settled that bare qualifications alone cannot establish the admissibility of … expert testimony.” United States v. Hermanek, 289 F.3d 1076, 1093 (9th Cir. 2002). Rather, we have interpreted Rule 702 to require that “[e]xpert testimony … be both relevant and reliable.” Estate of Barabin, 740 F.3d at 463 (alteration and ellipsis in original) (internal quotation marks omitted). A proposed expert’s testimony, then, must “have a reliable basis in the knowledge and experience of his discipline.” Kumho Tire, 526 U.S. at 148 (internal quotation marks omitted). This requires district courts, acting in a “gatekeeping role,” to assess “whether the reasoning or methodology underlying the testimony” is valid and “whether that reasoning or methodology properly can be applied to the facts in issue.” Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579, 592–93, 597 (1993) (“ Daubert I”). It is not “the correctness of the expert’s conclusions” that matters, but “the soundness of his methodology.” Estate of Barabin, 740 F.3d at 463 (internal quotation marks omitted).
The district court excluded the proposed testimony of Peter Schiff—a retired superintendent of a different school district who would have testified about “the finances of schools and high school athletic programs, as well as equitable access to school facilities at Castle Park,”—because it could not “discern what, if any, method he employed in arriving at his opinions.” The district court also found that Schiff’s “conclusions appear to be based on his personal opinions and speculation rather than on a systematic
