In Matrixx Initiatives, Inc. v. Siracusano, 131 S.Ct. 1309 (2011), the Supreme Court, speaking through Justice Sotomayor, wandered into a discussion whether statistical significance was necessary for a determination of the causality of an association:
“We note that courts frequently permit expert testimony on causation based on evidence other than statistical significance. See, e.g., Best v. Lowe’s Home Centers, Inc., 563 F. 3d 171, 178 (6th Cir 2009); Westberry v. Gislaved Gummi AB, 178 F. 3d 257, 263–264 (4th Cir. 1999) (citing cases); Wells v. Ortho Pharmaceutical Corp., 788 F. 2d 741, 744–745 (11th Cir. 1986). We need not consider whether the expert testimony was properly admitted in those cases, and we do not attempt to define here what constitutes reliable evidence of causation.”
Id. at 1319.
As I have pointed out previously, the Court’s citation to these three cases was jarring for their irrelevance, and for the questionable scholarship involved.
The first two cases cited involved differential etiology to assess specific causation, not general causation. As most courts have recognized, this assessment strategy requires that general causation has already been established. See, e.g., Hall v. Baxter Healthcare, 947 F. Supp. 1387 (D. Ore. 1996). These cases did not, therefore, even touch on the use of statistical significance to establish general causation. There was no statistical analysis in those cases, and nothing to judge significant or insignificant.
The citation to the third case, Wells, is noteworthy because the case has nothing to do with adverse event reports or the lack of statistical significance. Wells involved a claim of birth defects caused by the use of spermicidal jelly contraceptive, which had been the subject of several studies, one of which at least yielded a statistically significant increase in detected birth defects over what was expected. Wells v. Ortho Pharmaceutical Corp., 615 F. Supp. 262 (N.D. Ga. 1985), aff’d and rev’d in part on other grounds, 788 F.2d 741 (11th Cir.), cert. denied, 479 U.S.950 (1986). Wells could thus hardly be an example of a case in which there was a judgment of causation based upon a scientific study that lacked statistical significance in its findings. Of course, finding statistical significance is just the beginning of assessing the causality of an association; Wells was notorious for its poor assessment of all the determinants of scientific causation.
As I pointed out in Matrixx Unloaded, the citation to Wells was remarkable because the Wells decision has been widely criticized for its failure to evaluate the entire evidentiary display, as well as for its failure to rule out bias and confounding in the studies relied upon by the plaintiff.[i]
A few years later, another case in the same judicial district against the same defendant for the same product resulted in the grant of summary judgment. Smith v. Ortho Pharmaceutical Corp., 770 F. Supp. 1561, 1582 (N.D. Ga. 1991) (supposedly distinguishing Wells on the basis of more recent studies). Some legal scholars have been content to point out that the science had matured with the passage of time, from the point that there was sufficient evidence to support plaintiffs’ case (in Wells) to the point that the evidence was so overwhelmingly adverse to plaintiffs that summary judgment for the defense was appropriate (in Smith). While this suggestion has the virtue of simplicity, it fails to look at what really happened in Wells, and to analyze the evidence in front of the Wells court.
Another remarkable aspect of the Supreme Court’s citation to Wells is that the case, and all it stands for, was overruled sub silentio by the Supreme Court’s own decisions in Daubert, Joiner, Kumho Tire, and Weisgram. And if that did not kill the concept, then there was the simple matter of a supervening statute: the 2000 amendment of Rule 702, of Federal Rules of Evidence. Citing a case as jurisprudentially dead and discredited as Wells could have been sloppy scholarship and lawyering. The principle of charity, however, suggests it was purposeful, and that is a frightful prospect.
Katie Wells was conceived sometime in the month of October 1980. Her mother was using the defendant’s product, Ortho-Gynol Contraceptive Jelly, with its active ingredient, a non-ionic surfactant called p-diisobutylphenoxypolyethoxyethanol or octoxynol-9, from July until mid-November 1980. Defendant Ortho had manufactured and marketed this product since 1950, without any warning that the product causes birth defects. 615 F. Supp. at 268-69. Ortho’s defense consisted in denying general and specific causation, and noting that in the fall of 1980, “no published reports or studies had concluded that spermicides cause birth defects,” and that “it had received no other complaints nor had access to any other evidence suggesting a link between its Product and birth defects.” 615 F. Supp. at 269.
Key issues in Wells were whether the state of the art required a warning on product in 1980, when used, and whether, as of the time of the trial in 1984, plaintiffs could establish cause in fact.
The district judge, Judge Marvin Shoob, heard the case as the trier of fact. Both sides waived their rights to a jury trial in part because of the number of witnesses could not be accommodated within the time scheduled for the trial. Given that the plaintiffs called so many redundant witnesses, a reasonable observer may suspect that the plaintiffs wanted a bench trial. Perhaps there was something about the relationship between Katie’s mother and father to give plaintiffs’ counsel pause. Katie’s father, Mr. Gary Wells, was not a party; only her mother was claiming economic damages. Perhaps Katie’s father’s admitted substantial use of illegal, recreational drugs, pushed plaintiffs to make this choice. Katie’s mother admitted to using only therapeutic drugs, Decadron for bronchitis, and Amoxicillin during her pregnancy, but her father admitted to using LSD, amphetamines, methaqualone, and marijuana. Id. at 269. The defense probably agreed, hoping to avoid an unduly sympathetic jury, and to gain a more analytical decision maker.
Jurisdiction in Wells was based upon diversity of citizenship; the court was bound to apply Georgia law under controlling choice-of-law precedent. Georgia law requires plaintiffs to prove medical causation “reasonable degree of medical certainty.” See Parrott v. Chatham County Hospital Authority, 145 Ga.App. 113, 115, 243 S.E.2d 269 (1978); Robertson v. Emory University Hospital, 611 F.2d 604, 608 n. 13 (5th Cir.1980); Watson v. United States, 346 F.2d 52, 54 (5th Cir.1965), cert. denied, 382 U.S. 976 (1966). 615 F. Supp. at 295. Plaintiffs, under Georgia law, must show more than a “bare possibility” of causation, as well as ruling out other theories that are equally plausible. Id. (citing Maddox v. Houston County Hospital Authority, 158 Ga.App. 283, 284, 279 S.E.2d 732 (1981)).
According to Georgia law of negligence, a manufacturer must exercise reasonable care to warn of dangers of which it has “actual or constructive knowledge,” when the product was sold and delivered. Id. (citations omitted).
In deciding this case, Judge Shoob began defensively, on thin ice, by declaring that he had to make a “legal” decision, not a medical decision. Id. at 266. This defensive prelude was curious because Georgia law clearly imported “knowledge” into both the duty to warn, and into resolution of the causal issue. The requisite knowledge could come only from the scientific evidence that the parties tried to marshal. The defensive prelude was also curious because, as we shall see, Judge Shoob allowed the plaintiffs’ expert witnesses to opine about their subjective perceptions that warnings should be required upon suspicion of harm.
It bears pointing out that, as in Ferebee, Federal Rule of Evidence 702 or 703 is never mentioned in Judge Shoob’s decision. There appears to have been no defense challenges to the qualifications or the “helpfulness” of any of the plaintiffs’ witnesses. There are no challenges to any expert witness’s qualifications. There are no Frye challenges discussed.
On re-reading Judge Shoob’s opinion, the most salient feature is the absence of any discussion of the “point estimates” of association or “effect size” in any of the studies discussed. Similarly, Judge Shoob fails to mention the extent of the random error in any study, either in the form of p-values of in confidence intervals. There is an occasional hint that studies are too small to yield meaningful findings, but no power calculations or assessments are provided, and no alternative hypotheses specified. There is no consideration of multiple comparisons, which may have diluted the usual interpretation of significance probability. Judge Shoob failed to engage in the scientific studies or the evidence, which was offered to him as the trier of fact.
Notwithstanding the failure to consider important rules of evidence, and the scientific evidence, Judge Shoob appreciated that there was a failure of proof on the part of the plaintiffs:
“Although some of the studies suggested a connection between spermicides and birth defects, overall the studies failed to show conclusively whether or not the spermicide caused any or all of the birth defects suffered by Katie Wells.”
Id. at 266. How then did Ortho loose?
(to be continued).
[i] See, e.g., James L. Mills and Duane Alexander, “Teratogens and ‘Litogens’,” 15 New Engl. J. Med. 1234 (1986); Samuel R. Gross, “Expert Evidence,” 1991 Wis. L. Rev. 1113, 1121-24 (1991) (“Unfortunately, Judge Shoob’s decision is absolutely wrong. There is no scientifically credible evidence that Ortho-Gynol Contraceptive Jelly ever causes birth defects.”). See also Editorial, “Federal Judges v. Science,” N.Y. Times, December 27, 1986, at A22 (unsigned editorial); David E. Bernstein, “Junk Science in the Courtroom,” Wall St. J. at A 15 (Mar. 24,1993) (pointing to Wells as a prominent example of how the federal judiciary had embarrassed American judicial system with its careless, non-evidence based approach to scientific evidence); Bert Black, Francisco J. Ayala & Carol Saffran-Brinks, “Science and the Law in the Wake of Daubert: A New Search for Scientific Knowledge,” 72 Texas L. Rev. 715, 733-34 (1994) (lawyers and leading scientist noting that the district judge “found that the scientific studies relied upon by the plaintiffs’ expert were inconclusive, but nonetheless held his testimony sufficient to support a plaintiffs’ verdict. *** [T]he court explicitly based its decision on the demeanor, tone, motives, biases, and interests that might have influenced each expert’s opinion. Scientific validity apparently did not matter at all.”) (internal citations omitted); Troyen A. Brennan, “Untangling Causation Issues in Law and Medicine: Hazardous Substance Litigation,” 107 Ann. Intern. Med. 741, 744-45 (1987) (describing the result in Wells as arising from the difficulties created by the Ferebee case; “[t]he Wells case can be characterized as the court embracing the hypothesis when the epidemiologic study fails to show any effect”). Kenneth R. Foster, David E. Bernstein, and Peter W. Huber, eds., Phantom Risk: Scientific Inference and the Law 28-29, 138-39 (MIT Press 1993) (criticizing Wells decision); Hans Zeisel & David Kaye, Prove It With Figures: Empirical Methods in Law and Litigation § 6.5, at 93(1997) (noting the multiple comparisons in studies of birth defects among women who used spermicides, based upon the many reported categories of birth malformations, and the large potential for even more unreported categories); id. at § 6.5 n.3, at 271 (characterizing Wells as “notorious,” and noting that the case became a “lightning rod for the legal system’s ability to handle expert evidence.”).