For your delectation and delight, desultory dicta on the law of delicts.

Daubert’s Silver Anniversary – Retrospective View of Its Friends and Enemies

October 21st, 2018

Science is inherently controversial because when done properly it has no respect for power or political correctness or dogma or entrenched superstition. We should thus not be surprised that the scientific process has many detractors in houses of worship, houses of representatives, and houses of the litigation industry. And we have more than a few “Dred Scott” decisions, in which courts have held that science has no criteria of validity that they are bound to follow.

To be sure, many judges have recognized a different danger in scientific opinion testimony, namely, its ability to overwhelm the analytical faculties of lay jurors. Fact-finders may view scientific expert witness opinion testimony as having an overwhelming certainty and authority, which swamps their ability to evaluate the testimony.1

One errant judicial strategy to deal with their own difficulty in evaluating scientific evidence was to invent a fictitious divide between a scientific and legal burden of proof:2

Petitioners demand sole reliance on scientific facts, on evidence that reputable scientific techniques certify as certain. Typically, a scientist will not so certify evidence unless the probability of error, by standard statistical measurement, is less than 5%. That is, scientific fact is at least 95% certain. Such certainty has never characterized the judicial or the administrative process. It may be that the ‘beyond a reasonable doubt’ standard of criminal law demands 95% certainty. Cf. McGill v. United States, 121 U.S.App. D.C. 179, 185 n.6, 348 F.2d 791, 797 n.6 (1965). But the standard of ordinary civil litigation, a preponderance of the evidence, demands only 51% certainty. A jury may weigh conflicting evidence and certify as adjudicative (although not scientific) fact that which it believes is more likely than not.”

By falsely elevating the scientific standard, judges see themselves free to decide expeditiously and without constraints, because they are operating at much lower epistemic level.

Another response advocated by “the Lobby,” scientists in service to the litigation industry, has been to deprecate gatekeeping altogether. Perhaps the most brazen anti-science response to the Supreme Court’s decision in Daubert was advanced by David Michaels and his Project on Scientific Knowledge and Public Policy (SKAPP). In its heyday, SKAPP organized meetings and conferences, and cranked out anti-gatekeeping propaganda to the delight of the litigation industry3, while obfuscating and equivocating about the source of its funding (from the litigation industry).4

SKAPP principal David Michaels was also behind the efforts of the American Public Health Association (APHA) to criticize the judicial move to scientific standards in gatekeeping. In 2004, Michaels and fellow litigation industrialists prevailed upon the APHA to adopt a policy statement that attacked evidence-based science and data transparency in the form of “Policy Number: 2004-11 Threats to Public Health Science.”5

SKAPP appears to have gone the way of the dodo, although the defunct organization still has a Wikipedia­ page with the misleading claim that a federal court had funded its operation, and the old link for this sketchy outfit now redirects to the website for the Union of Concerned Scientists. In 2009, David Michaels, fellow in the Collegium Ramazzini, and formerly the driving force of SKAPP, went on to become an under-secretary of Labor, and OSHA administrator in the Obama administration.6

With the end of his regulatory work, Michaels is now back in the litigation saddle. In April 2018, Michaels participated in a ruse in which he allowed himself to be “subpoenaed” by Mark Lanier, to give testimony in a cases involving claims that personal talc use caused ovarian cancers.7 Michaels had no real subject matter expertise, but he readily made himself available so that Mr. Lanier could inject Michaels’ favorite trope of “doubt is their product” into his trial.

Against this backdrop of special pleading from the litigation industry’s go-to expert witnesses, it is helpful to revisit the Daubert decision, which is now 25 years old. The decision followed the grant of the writ of certiorari by the Supreme Court, full briefing by the parties on the merits, oral argument, and twenty two amicus briefs. Not all briefs are created equal, and this inequality is especially true of amicus briefs, for which the quality of argument, and the reputation of the interested third parties, can vary greatly. Given the shrill ideological ranting of SKAPP and the APHA, we might find some interest in what two leading scientific organizations, the American Association for the Advancement of Science (AAAS) and the National Academy of Science (NAS), contributed to the debate over the proper judicial role in policing expert witness opinion testimony.

The Amicus Brief of the AAAS and the NAS, filed in Daubert v. Merrell Dow Pharmaceuticals, Inc., U.S. Supreme Court No. 92-102 (Jan. 19, 1993), was submitted by Richard A. Meserve and Lars Noah, of Covington & Burling, and by Bert Black, of Weinberg & Green. Unfortunately, the brief does not appear to be available on Westlaw, but it was republished shortly after filing, at 12 Biotechnology Law Report 198 (No. 2, March-April 1993) [all citations below are to this republication].

The amici were and are well known to the scientific community. The AAAS is a not-for-profit scientific society, which publishes the prestigious journal Science, and engages in other activities to advance public understanding of science. The NAS was created by congressional charter in the administration of Abraham Lincoln, to examine scientific, medical, and technological issues of national significance. Brief at 208. Meserve, counsel of record for these Amici Curiae, is a member of the National Academy, a president emeritus of the Carnegie Institution for Science, and a former chair of the U.S. Nuclear Regulatory Commission. He received his doctorate in applied physics from Stanford University, and his law degree from Harvard. Noah is now a professor of law in the University of Florida, and Black is still a practicing lawyer, ironically for the litigation industry.

The brief of the AAAP and the NAS did not take a position on the merits of whether Bendectin can cause birth defects, but it had a great deal to say about the scientific process, and the need for courts to intervene to ensure that expert witness opinion testimony was developed and delivered with appropriate methodological rigor.

A Clear and Present Danger

The amici, AAAS and NAS, clearly recognized a threat to the integrity of scientific fact-finding in the regime of uncontrolled and unregulated expert witness testimony. The amici cited the notorious case of Wells v. Ortho Pharmaceutical Corp.8, which had provoked an outcry from the scientific community, and a particularly scathing article by two scientists from the National Institute of Child Health and Human Development.9

The amici also cited several judicial decisions on the need for robust gatekeeping, including the observations of Judge Jack Weinstein that

[t]he uncertainty of the evidence in [toxic tort] cases, dependent as it is on speculative scientific hypotheses and epidemiological studies, creates a special need for robust screening of experts and gatekeeping under Rules 403 and 703 by the court.”10

The AAAS and the NAS saw the “obvious danger that research results generated solely for litigation may be skewed.” Brief at 217& n.11.11 The AAAS and the NAS thus saw a real, substantial threat in countenancing expert witnesess who proffered “putatively scientific evidence that does not in fact reflect the application of scientific principles.” Brief at 208. The Supreme Court probably did not need the AAAS and the NAS to tell them that “[s]uch evidence can lead to incorrect decisions and can serve to discredit the contributions of science,” id., but it may have helped ensure that the Court articulated meaningful guidelines to trial judges to police their courtrooms against scientific conclusions that were not reached in accordance with scientific principles. The amici saw and stated that

[t]he unique persuasive power of scientific evidence and its inherent limitations requires that courts engage special efforts to ensure that scientific evidence is valid and reliable before it is admitted. In performing that task, courts can look to the same criteria that scientists themselves use to evaluate scientific claims.”

Brief at 212.

It may seem quaint to the post-modernists at the APHA, but the AAAS and the NAS were actually concerned “to avoid outcomes that are at odds with reality,” and they were willing to urge that “courts must exercise special care to assure that such evidence is based on valid and reliable scientific methodologies.” Brief at 209 (emphasis added). The amici also urged caution in allowing opinion testimony that conflicted with existing learning, and which had not been presented to the scientific community for evaluation. Brief at 218-19. In the words of the amici:

Courts should admit scientific evidence only if it conforms to scientific standards and is derived from methods that are generally accepted by the scientific community as valid and reliable. Such a test promotes sound judicial decisionmaking by providing workable means for screening and assessing the quality of scientific expert testimony in advance of trial.”

Brief at 233. After all, part of the scientific process itself is weeding out false ideas.

Authority for Judicial Control

The AAAS and NAS and its lawyers gave their full support to Merrill Dow’s position that “courts have the authority and the responsibility to exclude expert testimony that is based upon unreliable or misapplied methodologies.” Brief at 209. The Federal Rules of Evidence, and Rules 702, 703, and 403 in particular, gave trial courts “ample authority for empowering courts to serve as gatekeepers.” Brief at 230. The amici argued what ultimately would become the law, that judicial control, in the spirit and text of the Federal Rules, of “[t]hreshold determinations concerning the admissibility of scientific evidence are necessary to ensure accurate decisions and to avoid unnecessary expenditures of judicial resources on collateral issues. Brief at 210. The AAAS and NAS further recommended that:

Determinations concerning the admissibility of expert testimony based on scientific evidence should be made by a judge in advance of trial. Such judicial control is explicitly called for under Rule 104(a) of the Federal Rules of Evidence, and threshold admissibility determinations by a judge serve several important functions, including simplification of issues at trial (thereby increasing the speed of trial), improvement in the consistency and predictability of results, and clarification of the issues for purposes of appeal. Indeed, it is precisely because a judge can evaluate the evidence in a focused and careful manner, free from the prejudices that might infect deliberations by a jury, that the determination should be made as a threshold matter.”

Brief at 228 (internal citations omitted).

Criteria of Validity

The AAAS and NAS did not shrink from the obvious implications of their position. They insisted that “[i]n evaluating scientific evidence, courts should consider the same factors that scientists themselves employ to assess the validity and reliability of scientific assertions.” Brief at 209, 210. The amici may have exhibited an aspirational view of the ability of judges, but they shared their optimistic view that “judges can understand the fundamental characteristics that separate good science from bad.” Brief at 210. Under the gatekeeping regime contemplated by the AAAS and the NAS, judges would have to think and analyze, rather than delegating to juries. In carrying out their task, judges would not be starting with a blank slate:

When faced with disputes about expert scientific testimony, judges should make full use of the scientific community’s criteria and quality-control mechanisms. To be admissible, scientific evidence should conform to scientific standards and should be based on methods that are generally accepted by the scientific community as valid and reliable.”

Brief at 210. Questions such as whether an hypothesis has survived repeated severe, rigorous tests, whether the hypothesis is consistent with other existing scientific theories, whether the results of the tests have been presented to the scientific community, need to be answered affirmatively before juries are permitted to weigh in with their verdicts. Brief at 216, 217.

The AAAS and the NAS acknowledged implicitly and explicitly that courtrooms were not good places to trot out novel hypotheses, which lacked severe testing and sufficient evidentiary support. New theories must survive repeated testing and often undergo substantial refinements before they can be accepted in the scientific community. The scientific method requires nothing less. Brief at 219. These organizational amici also acknowledged that there will be occasionally “truly revolutionary advances” in the form of an hypothesis not fully tested. The danger of injecting bad science into broader decisions (such as encouraging meritless litigation, or the abandonment of useful products) should cause courts to view unestablished hypotheses with “heightened skepticism pending further testing and review.” Brief at 229. In other words, some hypotheses simply have not matured to the point at which they can support tort or other litigation.

The AAAS and the NAS contemplated that the gatekeeping process could and should incorporate the entire apparatus of scientific validity determinations into Rule 104(a) adjudications. Nowhere in their remarkable amicus brief do they suggest that if there some evidence (however weak) favoring a causal claim, with nothing yet available to weigh against it, expert witnesses can declare that they have the “weight of the evidence” on their side, and gain a ticket to the courthouse door. The scientists at SKAPP, or now those at the Union for Concerned Scientists, prefer to brand gatekeeping as a trick to sell “doubt.” What they fail to realize is that their propaganda threatens both universalism and organized skepticism, two of the four scientific institutional norms, described by sociologist of science Robert K. Merton.12

1 United States v. Brown, 557 F.2d 541, 556 (6th Cir. 1977) (“Because of its apparent objectivity, an opinion that claims a scientific basis is apt to carry undue weight with the trier of fact”); United States v. Addison, 498 F.2d 741, 744 (D.C. Cir. 1974) (“scientific proof may in some instances assume a posture of mystic infallibility in the eyes of a jury of laymen”). Some people say that our current political morass reflects poorly on the ability of United States citizens to assess and evaluate evidence and claims to the truth.

2 See, e.g., Ethyl Corp. v. EPA, 541 F.2d 1, 28 n.58 (D.C. Cir.), cert. denied, 426 U.S. 941 (1976). See also Rhetorical Strategy in Characterizing Scientific Burdens of Proof(Nov. 15, 2014).

3 See, e.g., Project on Scientific Knowledge and Public Policy, “Daubert: The Most Influential Supreme Court Ruling You’ve Never Heard Of(2003).

4 See, e.g., SKAPP A LOT(April 30, 2010); “Manufacturing Certainty(Oct. 25, 2011);David Michaels’ Public Relations Problem(Dec. 2, 2011); Conflicted Public Interest Groups (Nov. 3, 2013).

7 Notes of Testimony by David Michaels, in Ingham v. Johnson & Johnson, Case No. 1522-CC10417-01, St. Louis Circuit Ct, Missouri (April 17, 2018).

8 788 F.2d 741, 744-45 (11th Cir.), cert. denied, 479 U.S. 950 (1986). Remarkably, consultants for the litigation industry have continued to try to “rehabilitate” the Wells decision. SeeCarl Cranor’s Conflicted Jeremiad Against Daubert” (Sept. 23, 2018).

9 James L. Mills & Duane Alexander, “Teratogens and Litogens,” 315 New Engl. J. Med. 1234, 1235 (1986).

10 Brief at n. 31, citing In re Agent Orange Product Liab. Litig., 611 F. Supp. 1267, 1269 (E.D.N.Y. 1985), aff’d, 818 F.2d 187 (2th Cir. 1987), cert. denied, 487 U.S. 1234 (1988).

11 citing among other cases, Perry v. United States, 755 F.2d 888, 892 (11th Cir. 1985) (“A scientist who has a formed opinion as to the answer he is going to find before he even begins his research may be less objective than he needs to be in order to produce reliable scientific results.”).

12 Robert K. Merton, “The Normative Structure of Science,” in Robert K. Merton, The Sociology of Science: Theoretical and Empirical Investigations, chap. 13, at 267, 270 (1973).

The Expert Witness Who Put God on His Reference List

August 28th, 2018

And you never ask questions
When God’s on your side”

                                Bob Dylan, “With God on Our Side” 1963.

Cases involving claims of personal injury have inspired some of the most dubious scientific studies in the so-called medical literature, but the flights of fancy in published papers are nothing compared with what is recorded in the annals of expert witness testimony. The weaker the medical claims, the more outlandish is the expert testimony proffered. Claims for personal injury supposedly resulting from mold exposure are no exception to the general rule. The expert witness opinion testimony in mold litigation has resulted in several commentaries1 and professional position papers,2 offered to curb the apparent excesses.

Ritchie Shoemaker, M.D., has been a regular expert witness for the mold lawsuit industry. Professional criticism has not deterred Shoemaker, although discerning courts have put the kibosh on some of Shoemaker’s testimonial adventures.3

Shoemaker cannot be everywhere, and so in conjunction with the mold lawsuit industry, Shoemaker has taken to certifying new expert witnesses. But how will Shoemaker and his protégées overcome the critical judicial reception?

Enter Divine Intervention

Make thee an ark of gopher wood; rooms shalt thou make in the ark, and shalt pitch it within and without with pitch.4

Some say the age of prophets, burning bushes, and the like is over, but perhaps not so. Maybe God speaks to expert witnesses to fill in the voids left by missing evidence. Consider the testimony of Dr. Scott W. McMahon, who recently testified that he was Shoemaker trained, and divinely inspired:

Q. Jumping around a little bit, Doctor, how did your interest in indoor environmental quality in general, and mold in particular, how did that come about?

A. I had — in 2009, I had been asked to give a talk at a medical society at the end of October and the people who were involved in it were harassing me almost on a weekly basis asking me what the title of my talk was going to be. I had spoken to the same society the previous four years. I had no idea what I was going to speak about. I am a man of faith, I’ve been a pastor and a missionary and other things, so I prayed about it and what I heard in my head verbatim was pediatric mold exposure colon the next great epidemic question mark. That’s what I heard in my head. And so because I try to live by faith, I typed that up as an email and said this is the name of my topic. And then I said, okay, God, you have ten weeks to teach me about this, and he did. Within three, four weeks maybe five, he had connected me to Dr. Shoemaker who was the leading person in the world at that time and the discoverer of this chronic inflammatory response.


I am a man of faith, I’ve been a pastor and everything. And I realized that this was a real entity.


Q. And do you attribute your decision or the decision for you to start Whole World Health Care also to be a divine intervention?

A. Well, that certainly started the process but I used my brain, too. Like I said, I went and I investigated Dr. Shoemaker, I wanted to make sure that his methods were real, that he wasn’t doing, you know, some sort of voodoo medicine and I saw that he wasn’t, that his scientific practice was standard. I mean, he changes one variable at a time in tests. He tested every step of the way. And I found that his conclusions were realistic. And then, you know, over the last few years, I’ve 1 gathered my own data and I see that they confirm almost every one of his conclusions.

Q. Doctor, was there anything in your past or anything dealing with your family in terms of exposure to mold or other indoor health issues?

A. No, it was totally off my radar.

Q. *** I’m not going to go into great detail with respect to Dr. Shoemaker, but are you Shoemaker certified?

A. I am.

Deposition transcript of Dr. Scott W. McMahon, at pp.46-49, in Courcelle v. C.W. Nola Properties LLC, Orleans Parish, Louisiana No. 15-3870, Sec. 7, Div. F. (May 18, 2018).

You may be surprised that the examining lawyer did not ask about the voice in which God spoke. The examining lawyer seems to have accepted without further question that the voice was that of an adult male voice. Still did the God entity speak in English, or in tongues? Was it a deep, resonant voice like Morgan Freeman’s in Bruce Almighty (2003)? Or was it a Yiddische voice like George Burns, in Oh God (1977)? Were there bushes burning when God spoke to McMahon? Or did the toast burn darker than expected?

Some might think that McMahon was impudent if not outright blasphemous for telling God that “He” had 10 weeks in which to instruct McMahon in the nuances of how mold causes human illness. Apparently, God was not bothered by this presumptuousness and complied with McMahon, which makes McMahon a special sort of prophet.

Of course, McMahon says he used his “brain,” in addition to following God’s instructions. But really why bother? Were there evidentiary or inferential gaps filled in by the Lord? The deposition does not address this issue.

In federal court, and in many state courts, an expert witness may base opinions on facts or data that are not admissible if, and only if, expert witnesses “in the particular field would reasonably rely on those kinds of facts or data in forming an opinion on the subject.5

Have other expert witnesses claimed divine inspiration for opinion testimony? A quick Pubmed search does not reveal any papers by God, or papers with God as someone’s Co-Author. It is only a matter of time, however, before a judge, some where, takes judicial notice of divinely inspired expert witness testimony.

1 See, e.g., Howard M. Weiner, Ronald E. Gots, and Robert P. Hein, “Medical Causation and Expert Testimony: Allergists at this Intersection of Medicine and Law,” 12 Curr. Allergy Asthma Rep. 590 (2012).

2 See, e.g., Bryan D. Hardin, Bruce J. Kelman, and Andrew Saxon, “ACOEM Evidence-Based Statement: Adverse Human Health Effects Associated with Molds in the Indoor Environment,” 45 J. Occup. & Envt’l Med. 470 (2003).

3 See, e.g., Chesson v. Montgomery Mutual Insur. Co., 434 Md. 346, 75 A.3d 932, 2013 WL 5311126 (2013) (“Dr. Shoemaker’s technique, which reflects a dearth of scientific methodology, as well as his causal theory, therefore, are not shown to be generally accepted in the relevant scientific community.”); Young v. Burton, 567 F. Supp. 2d 121, 130-31 (D.D.C. 2008) (excluding Dr. Shoemaker’s theories as lacking general acceptance and reliability; listing Virginia, Florida, and Alabama as states in which courts have rejected Shoemaker’s theory).

4 Genesis 6:14 (King James translation).

5 Federal Rule of Evidence. Bases of an Expert.

Failed Gatekeeping in Ambrosini v. Labarraque (1996)

December 28th, 2017

The Ambrosini case straddled the Supreme Court’s 1993 Daubert decision. The case began before the Supreme Court clarified the federal standard for expert witness gatekeeping, and ended in the Court of Appeals for the District of Columbia, after the high court adopted the curious notion that scientific claims should be based upon reliable evidence and valid inferences. That notion has only slowly and inconsistently trickled down to the lower courts.

Given that Ambrosini was litigated in the District of Columbia, where the docket is dominated by regulatory controversies, frequently involving dubious scientific claims, no one should be surprised that the D.C. Court of Appeals did not see that the Supreme Court had read “an exacting standard” into Federal Rule of Evidence 702. And so, we see, in Ambrosini, this Court of Appeals citing and purportedly applying its own pre-Daubert decision in Ferebee v. Chevron Chem. Co., 552 F. Supp. 1297 (D.D.C. 1982), aff’d, 736 F.2d 1529 (D.C. Cir.), cert. denied, 469 U.S. 1062 (1984).1 In 2000, the Federal Rule of Evidence 702 was revised in a way that extinguishes the precedential value of Ambrosini and the broad dicta of Ferebee, but some courts and commentators have failed to stay abreast of the law.

Escolastica Ambrosini was using a synthetic progestin birth control, Depo-Provera, as well as an anti-nausea medication, Bendectin, when she became pregnant. The child that resulted from this pregnancy, Teresa Ambrosini, was born with malformations of her face, eyes, and ears, cleft lip and palate, and vetebral malformations. About three percent of all live births in the United States have a major malformation. Perhaps because the Divine Being has sovereign immunity, Escolastica sued the manufacturers of Bendectin and Depo-Provera, as well as the prescribing physician.

The causal claims were controversial when made, and they still are. The progestin at issue, medroxyprogesterone acetate (MPA), was embryotoxic in the cynomolgus monkey2, but not in the baboon3. The evidence in humans was equivocal at best, and involved mostly genital malformations4; the epidemiologic evidence for the MPA causal claim to this day remains unconvincing5.

At the close of discovery in Ambrosini, Upjohn (the manufacturer of the progestin) moved for summary judgment, with a supporting affidavit of a physician and geneticist, Dr. Joe Leigh Simpson. In his affidavit, Simpson discussed three epidemiologic studies, as well as other published papers, in support of his opinion that the progestin at issue did not cause the types of birth defects manifested by Teresa Ambrosini.

Ambrosini had disclosed two expert witnesses, Dr. Allen S. Goldman and Dr. Brian Strom. Neither Goldman nor Strom bothered to identify the papers, studies, data, or methodology used in arriving at an opinion on causation. Not surprisingly, the district judge was unimpressed with their opposition, and granted summary judgment for the defendant. Ambrosini v. Labarraque, 966 F.2d 1462, 1466 (D.C. Cir. 1992).

The plaintiffs appealed on the remarkable ground that Goldman’s and Strom’s crypto-evidence satisfied Federal Rule of Evidence 703. Even more remarkably, the Circuit, in a strikingly unscholarly opinion by Judge Mikva, opined that disclosure of relied-upon studies was not required for expert witnesses under Rules 703 and 705. Judge Mikva seemed to forget that the opinions being challenged were not given in testimony, but in (late-filed) affidavits that had to satisfy the requirement of Federal Rule of Civil Procedure 26. Id. at 1468-69. At trial, an expert witness may express an opinion without identifying its bases, but of course the adverse party may compel disclosure of those bases. In discovery, the proffered expert witness must supply all opinions and evidence relied upon in reach the opinions. In any event, the Circuit remanded the case for a hearing and further proceedings, at which the two challenged expert witnesses, Goldman and Strom, would have to identify the bases of their opinions. Id. at 1471.

Not long after the case landed back in the district court, the Supreme Court decided Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993). With an order to produce entered, plaintiffs’ counsel could no longer hide Goldman and Strom’s evidentiary bases, and their scientific inferences came under judicial scrutiny.

Upjohn moved again to exclude Goldman and Strom’s opinions. The district court upheld Upjohn’s challenges, and granted summary judgment in favor of Upjohn for the second time. The Ambrosinis appealed again, but the second case in the D.C. Circuit resulted in a split decision, with the majority holding that the exclusion of Goldman and Strom’s opinions under Rule 702 was erroneous. Ambrosini v. Labarraque, 101 F.3d 129 (D.C. Cir. 1996).

Although issued two decades ago, the majority’s opinion remains noteworthy as an example of judicial resistance to the existence and meaning of the Supreme Court’s Daubert opinion. The majority opinion uncritically cited the notorious Ferebee6 and other pre-Daubert decisions. The court embraced the Daubert dictum about gatekeeping being limited to methodologic consideration, and then proceeded to interpret methodology as superficially as necessary to sustain admissibility. If an expert witness claimed to have looked at epidemiologic studies, and epidemiology was an accepted methodology, then the opinion of the expert witness must satisfy the legal requirements of Daubert, or so it would seem from the opinion of the U.S. Court of Appeals for the District of Columbia.

Despite the majority’s hand waving, a careful reader will discern that there must have been substantial gaps and omissions in the explanations and evidence cited by plaintiffs’ expert witnesses. Seeing anything clearly in the Circuit’s opinion is made difficult, however, by careless and imprecise language, such as its descriptions of studies as showing, or not showing “causation,” when it could have meant only that such studies showed associations, with more or less random and systematic error.

Dr. Strom’s report addressed only general causation, and even so, he apparently did not address general causation of the specific malformations manifested by the plaintiffs’ child. Strom claimed to have relied upon the “totality of the data,” but his methodologic approach seems to have required him to dismiss studies that failed to show an association.

Dr. Strom first set forth the reasoning he employed that led him to disagree with those studies finding no causal relationship [sic] between progestins and birth defects like Teresa’s. He explained that an epidemiologist evaluates studies based on their ‘statistical power’. Statistical power, he continued, represents the ability of a study, based on its sample size, to detect a causal relationship. Conventionally, in order to be considered meaningful, negative studies, that is, those which allege the absence of a causal relationship, must have at least an 80 to 90 percent chance of detecting a causal link if such a link exists; otherwise, the studies cannot be considered conclusive. Based on sample sizes too small to be reliable, the negative studies at issue, Dr. Strom explained, lacked sufficient statistical power to be considered conclusive.”

Id. at 1367.

Putting aside the problem of suggesting that an observational study detects a “causal relationship,” as opposed to an association in need of further causal evaluation, the Court’s précis of Strom’s testimony on power is troublesome, and typical of how other courts have misunderstood and misapplied the concept of statistical power. Statistical power is a probability of observing an association of a specified size at a specified level of statistical significance. The calculation of statistical power turns indeed on sample size, the level of significance probability preselected for “statistical significance, an assumed probability distribution of the sample, and, critically, an alternative hypothesis. Without a specified alternative hypothesis, the notion of statistical power is meaningless, regardless of what probability (80% or 90% or some other percentage) is sought for finding the alternative hypothesis. Furthermore, the notion that the defense must adduce studies with “sufficient statistical power to be considered conclusive” creates an unscientific standard that can never be met, while subverting the law’s requirement that the claimant establish causation.

The suggestion that the studies that failed to find an association cannot be considered conclusive because they “lacked sufficient statistical power” is troublesome because it distorts and misapplies the very notion of statistical power. No attempt was made to describe the confidence intervals surrounding the point estimates of the null studies; nor was there any discussion whether the studies could be aggregated to increase their power to rule out meaningful associations.

The Circuit court’s scientific jurisprudence was thus seriously flawed. Without a discussion of the end points observed, the relevant point estimates of risk ratios, and the confidence intervals, the reader cannot assess the strength of the claims made by Goldman and Strom, or by defense expert Simpson, in their reports. Without identifying the study endpoints, the reader cannot evaluate whether the plaintiffs’ expert witnesses relied upon relevant outcomes in formulating their opinions. The court viewed the subject matter from 30,000 feet, passing over at 600 mph, without engagement or care. A strong dissent, however, suggested serious mischaracterizations of the plaintiffs’ evidence by the majority.

The only specific causation testimony to support plaintiff’s claims came from Goldman, in what appears to have been a “differential etiology.” Goldman purported to rule out a genetic cause, even though he had not conducted a critical family history or ordered a state-of-the-art chromosomal study. Id. at 140. Of course, nothing in a differential etiology approach would allow a physician to rule out “unknown” causes, which, for birth defects, make up the most prevalent and likely causes to explain any particular case. The majority acknowledged that these were short comings, but rhetorically characterized them as substantive, not methodologic, and therefore as issues for cross-examination, not for consideration by a judicial gatekeeping. All this is magical thinking, but it continues to infect judicial approaches to specific causation. See, e.g., Green Mountain Chrysler Plymouth Dodge Jeep v. Crombie, 508 F. Supp. 2d 295, 311 (D.Vt. 2007) (citing Ambrosini for the proposition that “the possibility of uneliminated causes goes to weight rather than admissibility, provided that the expert has considered and reasonably ruled out the most obvious”). In Ambrosini, however, Dr. Goldman had not ruled out much of anything.

Circuit Judge Karen LeCraft Henderson dissented in a short, but pointed opinion that carefully marshaled the record evidence. Drs. Goldman and Strom had relied upon a study by Greenberg and Matsunaga, whose data failed to show a statistically significant association between MPA and cleft lip and palate, when the crucial issue of timing of exposure was taken into consideration. Ambrosini, 101 F.3d at 142.

Beyond the specific claims and evidence, Judge Henderson anticipated the subsequent Supreme Court decisions in Joiner, Kumho Tire, and Weisgram, and the year 2000 revision of Rule 702, in noting that the majority’s acceptance of glib claims to have used a “traditional methodology” would render Daubert nugatory. Id. at 143-45 (characterizing Strom and Goldman’s methodologies as “wispish”). Even more importantly, Judge Henderson refused to indulge the assumption that somehow the length of Goldman’s C.V. substituted for evidence that his methods satisfied the legal (or scientific) standard of reliability. Id.

The good news is that little or nothing in Ambrosini survives the 2000 amendment to Rule 702. The bad news is that not all federal judges seem to have noticed, and that some commentators continue to cite the case, as lovely.

Probably no commentator has promiscuously embraced Ambrosini as warmly as Carl Cranor, a philosopher, and occasional expert witness for the lawsuit industry, in several publications and presentations.8 Cranor has been particularly enthusiastic about Ambrosini’s approval of expert witness’s testimony that failed to address “the relative risk between exposed and unexposed populations of cleft lip and palate, or any other of the birth defects from which [the child] suffers,” as well as differential etiologies that exclude nothing.9 Somehow Cranor, as did the majority in Ambrosini, believes that testimony that fails to identify the magnitude of the point estimate of relative risk can “assist the trier of fact to understand the evidence or to determine a fact in issue.”10 Of course, without that magnitude given, the trier of fact could not evaluate the strength of the alleged association; nor could the trier assess the probability of individual causation to the plaintiff. Cranor also has written approvingly of lumping unrelated end points, which defeats the assessment of biological plausibility and coherence by the trier of fact. When the defense expert witness in Ambrosini adverted to the point estimates for relevant end points, the majority, with Cranor’s approval, rejected the null findings as “too small to be significant.”11 If the null studies were, in fact, too small to be useful tests of the plaintiffs’ claims, intellectual and scientific honesty required an acknowledgement that the evidentiary display was not one from which a reasonable scientist would draw a causal conclusion.

1Ambrosini v. Labarraque, 101 F.3d 129, 138-39 (D.C. Cir. 1996) (citing and applying Ferebee), cert. dismissed sub nom. Upjohn Co. v. Ambrosini, 117 S.Ct. 1572 (1997) See also David E. Bernstein, “The Misbegotten Judicial Resistance to the Daubert Revolution,” 89Notre Dame L. Rev. 27, 31 (2013).

2 S. Prahalada, E. Carroad, M. Cukierski, and A.G. Hendrickx, “Embryotoxicity of a single dose of medroxyprogesterone acetate (MPA) and maternal serum MPA concentrations in cynomolgus monkey (Macaca fascicularis),” 32 Teratology 421 (1985).

3 S. Prahalada, E. Carroad, and A.G. Hendrick, “Embryotoxicity and maternal serum concentrations of medroxyprogesterone acetate (MPA) in baboons (Papio cynocephalus),” 32 Contraception 497 (1985).

4 See, e.g., Z. Katz, M. Lancet, J. Skornik, J. Chemke, B.M. Mogilner, and M. Klinberg, “Teratogenicity of progestogens given during the first trimester of pregnancy,” 65 Obstet Gynecol. 775 (1985); J.L. Yovich, S.R. Turner, and R. Draper, “Medroxyprogesterone acetate therapy in early pregnancy has no apparent fetal effects,” 38 Teratology 135 (1988).

5 G. Saccone, C. Schoen, J.M. Franasiak, R.T. Scott, and V. Berghella, “Supplementation with progestogens in the first trimester of pregnancy to prevent miscarriage in women with unexplained recurrent miscarriage: a systematic review and meta-analysis of randomized, controlled trials,” 107 Fertil. Steril. 430 (2017).

6 Ferebee v. Chevron Chemical Co., 736 F.2d 1529, 1535 (D.C. Cir.), cert. denied, 469 U.S. 1062 (1984).

7 Dr. Strom was also quoted as having provided a misleading definition of statistical significance: “whether there is a statistically significant finding at greater than 95 percent chance that it’s not due to random error.” Ambrosini at 101 F.3d at 136. Given the majority’s inadequate description of the record, the description of witness testimony may not be accurate, and error cannot properly be allocated.

8 Carl F. Cranor, Toxic Torts: Science, Law, and the Possibility of Justice 320, 327-28 (2006); see also Carl F. Cranor, Toxic Torts: Science, Law, and the Possibility of Justice 238 (2d ed. 2016).

9 Carl F. Cranor, Toxic Torts: Science, Law, and the Possibility of Justice 320 (2006).

10 Id.

11 Id. ; see also Carl F. Cranor, Toxic Torts: Science, Law, and the Possibility of Justice 238 (2d ed. 2016).

Gatekeeping of Expert Witnesses Needs a Bair Hug

December 20th, 2017

For every Rule 702 (“Daubert”) success story, there are multiple gatekeeping failures. See David E. Bernstein, “The Misbegotten Judicial Resistance to the Daubert Revolution,” 89 Notre Dame L. Rev. 27 (2013).1 Exemplars of inadequate expert witness gatekeeping in state or federal court abound, and overwhelm the bar. The only solace one might find is that the abuse-of-discretion appellate standard of review keeps the bad decisions from precedentially outlawing the good ones.

Judge Joan Ericksen recently provided another Berenstain Bears’ example of how not to keep the expert witness gate, in litigation claims that the Bair Hugger forced air warming devices (“Bair Huggers”) cause infections. In re Bair Hugger Forced Air Warming, MDL No. 15-2666, 2017 WL 6397721 (D. Minn. Dec. 13, 2017). Although Her Honor properly cited and quoted Rule 702 (2000), a new standard is announced in a bold heading:

Under Federal Rule of Evidence 702, the Court need only exclude expert testimony that is so fundamentally unsupported that it can offer no assistance to the jury.”

Id. at *1. This new standard thus permits largely unsupported opinion that can offer bad assistance to the jury. As Judge Ericksen demonstrates, this new standard, which has no warrant in the statutory text of Rule 702 or its advisory committee notes, allows expert witnesses to rely upon studies that have serious internal and external validity flaws.

Jonathan Samet, a specialist in pulmonary medicine, not infectious disease or statistics, is one of the plaintiffs’ principal expert witnesses. Samet relies in large measure upon an observational study2, which purports to find an increased odds ratio for use of the Bair Hugger among infection cases in one particular hospital. The defense epidemiologist, Jonathan B. Borak, criticized the McGovern observational study on several grounds, including that the study was highly confounded by the presence of other known infection risks. Id. at *6. Judge Ericksen characterized Borak’s opinion as an assertion that the McGovern study was an “insufficient basis” for the plaintiffs’ claims. A fair reading of even Judge Ericksen’s précis of Borak’s proffered testimony requires the conclusion that Borak’s opinion was that the McGovern study was invalid because of data collection errors and confounding. Id.

Judge Ericksen’s judicial assessment, taken from the disagreement between Samet and Borak, is that there are issues with the McGovern study, which go to “weight of the evidence.” This finding obscures, however, that there were strong challenges to the internal and external validity of the study. Drawing causal inferences from an invalid observational study is a methodological issue, not a weight-of-the-evidence problem for the jury to resolve. This MDL opinion never addresses the Rule 703 issue, whether an epidemiologic expert would reasonably rely upon such a confounded study.

The defense proffered the opinion of Theodore R. Holford, who criticized Dr. Samet for drawing causal inferences from the McGovern observational study. Holford, a professor of biostatistics at Yale University’s School of Public Health, analyzed the raw data behind the McGovern study. Id. at *8. The plaintiffs challenged Holford’s opinions on the ground that he relied on data in “non-final” form, from a temporally expanded dataset. Even more intriguingly, given that the plaintiffs did not present a statistician expert witness, plaintiffs argued that Holford’s opinions should be excluded because

(1) he insufficiently justified his use of a statistical test, and

(2) he “emphasizes statistical significance more than he would in his professional work.”


The MDL court dismissed the plaintiffs’ challenge on the mistaken conclusion that the alleged contradictions between Holford’s practice and his testimony impugn his credibility at most.” If there were truly such a deviation from the statistical standard of care, the issue is methodological, not a credibility issue of whether Holford was telling the truth. And as for the alleged over-emphasis on statistical significance, the MDL court again falls back to the glib conclusions that the allegation goes to the weight, not the admissibility of expert witness opinion testimony, and that plaintiffs can elicit testimony from Dr Samet as to how and why Professor Holford over-emphasized statistical significance. Id. Inquiring minds, at the bar, and in the academy, are left with no information about what the real issues are in the case.

Generally, both sides’ challenges to expert witnesses were denied.3 The real losers, however, were the scientific and medical communities, bench, bar, and general public. The MDL court glibly and incorrectly treated methodological issues as “credibility” issues, confused sufficiency with validity, and banished methodological failures to consideration by the trier of fact for “weight.” Confounding was mistreated as simply a debating point between the parties’ expert witnesses. The reader of Judge Ericksen’s opinion never learns what statistical test was used by Professor Holford, what justification was needed but allegedly absent for the test, why the justification was contested, and what other test was alleged by plaintiffs to have been a “better” statistical test. As for the emphasis given statistical significance, the reader is left in the dark about exactly what that emphasis was, and how it led to Holford’s conclusions and opinions, and what the proper emphasis should have been.

Eventually appellate review of the Bair Hugger MDL decision must turn on whether the district court abused its discretion. Although appellate courts give trial judges discretion to resolve Rule 702 issues, the appellate courts cannot reach reasoned decisions when the inferior courts fail to give even a cursory description of what the issues were, and how and why they were resolved as they were.

2 P. D. McGovern, M. Albrecht, K. G. Belani, C. Nachtsheim, P. F. Partington, I. Carluke, and M. R. Reed, “Forced-Air Warming and Ultra-Clean Ventilation Do Not Mix: An Investigation of Theatre Ventilation, Patient Warming and Joint Replacement Infection in Orthopaedics,” 93 J. Bone Joint 1537 (2011). The article as published contains no disclosures of potential or actual conflicts of interest. A persistent rumor has it that the investigators were funded by a commercial rival to the manufacturer of the Bair Hugger at issue in Judge Ericksen’s MDL. See generally, Melissa D. Kellam, Loraine S. Dieckmann, and Paul N. Austin, “Forced-Air Warming Devices and the Risk of Surgical Site Infections,” 98 Ass’n periOperative Registered Nurses (AORN) J. 354 (2013).

3 A challenge to plaintiffs’ expert witness Yadin David was sustained to the extent he sought to offer opinions about the defendant’s state of mind. Id. at *5.