From Lofton v. McNeil Consumer & Specialty Pharm., 2010 U.S. Dist. LEXIS 6390 (N.D. Tex. Jan. 27, 2010):

The court next considers Defendants' argument that [ Merrell Dow Pharmaceuticals, Inc. v. Havner, 953 S.W.2d 706 (Tex. 1997)] controls the court's determination of relevancy in the context of the admissibility of expert testimony in a medical case such as this. In Havner, the Texas Supreme Court considered whether there was legally sufficient evidence that the drug Bendectin caused plaintiff to be born with a birth defect. 953 S.W.2d at 708. That court framed the issue as "whether the [plaintiffs'] evidence is scientifically reliable and thus some evidence to support the judgment in their favor." ... The Havner court held that to establish some evidence of general causation, epidemiological studies must meet three standards. First, the study must show "more than a doubling of the risk" due to exposure. ... Second, the study must have a confidence interval that does not include 1.0. ... Third, the study must have a confidence level of at least 95 percent. ***

The United States Court of Appeals for the Fifth Circuit has considered the Havner decision, but only in the context of determining the legal sufficiency of evidence supporting a jury verdict. In that case, although the parties appealed both the sufficiency of the evidence and the court's expert admissibility rulings, the initial panel hearing the case applied Havner only to its discussion of the sufficiency of the evidence to support the jury's finding. Bartley v. Euclid, Inc., 158 F.3d 272 (5th Cir. 1998), vacated, 169 F.3d 215 (5th Cir. 1999) ("Bartley I"). When that case was heard en banc, the court did not address the applicability of Havner to the admissibility determination, instead focusing on the Daubertcriteria. Barley v. Euclid, Inc., 180 F.3d 175, 179 (5th Cir. 1999) ("Bartley II").

District courts in this circuit have reached different results in determining whether Havner applies to a federal court's ruling on the admissibility of expert testimony. At least one court in this district rejected the application of Havner to the determination of whether expert testimony is admissible. In Taylor v. Bristol-Myers Squibb Co., 2004 WL 2058796 (N.D. Tex. 2004) (Cummings, J.), the court distinguished between the legal sufficiency of evidence to prove a claim and the legal standard for admissibility of expert evidence:

This Court is of the opinion that Havner does not clearly establish substantive state law that would control the admissibility of expert testimony or scientific evidence in a federal court sitting in diversity. The issue of Havner was not the admissibility of evidence but rather the legal sufficiency of the evidence offered to establish causation, and the holding of the case addressed only that legal sufficiency issue.

***Another district court considering the same issue has held that the Havner standards should apply in determining the admissibility of expert evidence:

If evidence is admissible under federal procedural law but fails to constitute "some evidence" under Texas substantive law, the Plaintiffs' victory on the admissibility question would be a hollow one, as the evidence would be deemed insufficient as a matter of law to survive summary judgment. Moreover, whether expert testimony will assist the trier of fact is governed in part by whether the testimony is relevant to the plaintiff's burden of proof under the substantive law, and testimony that will not assist the trier of fact by advancing an element of the plaintiff's case should be excluded.

Cano v. Everest Minerals Corp., 362 F. Supp. 2d 814, 821-22 (W.D. Tex. 2005) (Rodriguez, J.) (citation omitted). That court concluded that "Havner controls the issue of what evidence is required to establish causation in a toxic tort case and therefore what evidence is relevant."... [s]ee also Burton v. Wyeth-Ayerst Labs. Div. of American Home Prods. Corp., 513 F. Supp. 2d 719, 730 n.12 (N.D. Tex. 2007) (Fish, J.) (holding in dicta that " Havner’s standards are substantive, not procedural requirements.") (citation omitted).

Other courts, including the Fifth Circuit, have applied Havner to determine the legal sufficiency of the evidence supporting causation but have not reached the question of whether its standards apply in the context of a Daubertchallenge. ***

Regardless of the court's decision regarding the applicability of Havner in this context, the court will necessarily have to consider Plaintiffs' expert reports in light of Havner when determining the summary judgment motion. The court understands the practical decision of the court in Cano that evidence that may be admissible but that fails to be legally sufficient to prove general causation should be excluded. This decision, however, conflates the standards under Daubertand the ultimate question of whether there is legally sufficient evidence of causation. The court determines that the magistrate judge is correct and will follow Taylor ; it finds that Havner does not control a federal court's determination of admissibility pursuant to Rule 702 and Daubert. The court notes, however, that even if this decision is incorrect, in the context of this case, Defendants' objection would be moot because in ruling on the motion for summary judgment the court will consider the sufficiency of the epidemiological studies under the standards set forth in Havner.