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

Bad Gatekeeping or Missed Opportunity – Allen v. Martin Surfacing

November 30th, 2012

Sometimes when federal courts permit dubious causation opinion testimony over Rule 702 objections, the culprit is bad lawyering by the opponent of the proffered testimony.  Allen v. Martin Surfacing, 263 F.R.D. 47 (D. Mass. 2009), may be an important example.


Daniel Allen was the former football coach of the College of The Holy Cross, in Worcester, Massachusetts.  In spring of 2001, defendant Martin Surfacing refinished the gymnasium floor at the college.  Coach Allen was exposed to solvent fumes, including toluene fumes, during defendant’s work, as well as for a couple of months afterwards.   While exposed, Allen experienced “dizziness, headaches, and disorientation.” 263 F.R.D. at 51.  After the gym floor resurfacing was completed, Allen experienced other symptoms, such as fatigue, muscle weakness, and fasciculations in his lower limbs.  In January 2002, at the age of 45, Allen was diagnosed with amyotrophic lateral sclerosis (ALS).  Id. Allen’s condition progressed, and he died three years later, in May 2004.  Id. at 52.

Allen’s family sued for wrongful death.  The parties’ apparently agreed on the following:

  • ALS occurs as a sporadic ALS, as well as “familial ALS,”
  • the cause of sporadic ALS is unknown,
  • Allen developed and died of sporadic ALS,
  • no air sampling established overexposure to any chemical,
  • there were no reliable exposure models to quantify Allen’s exposures,
  • there are no known causes of sporadic ALS, and
  • toluene did not cause Allen’s ALS

Remarkably, defendant lost the Rule 702 challenge to plaintiffs’ expert witnesses’ opinion testimony.  It is easy to suspect that the district judge was sleep at the gate, and that his gatekeeping was deficient.  A close read of the opinion supports the view that this was not Rule 702’s finest moment, but much more was going on to get to admissibility.

First, the plaintiffs’ counsel cleverly avoided running into a wall by avoiding a claim that toluene caused Allen’s ALS. Instead, plaintiffs’ claimed that toluene accelerated the onset of the disease.  This claim was equally dubious, but it allowed the expert witnesses to avoid a mountain of medical opinion, authoritative and well-supportive, that there is no known cause of sporadic ALS.

Second, the plaintiffs’ counsel took the initiative by filing an affirmative motion to admit the testimony of their expert witnesses.  Rather than ceding the initiative to the defendant, the plaintiffs seized the initiative and had the first and last word on admissibility.  As a result, plaintiffs were able to present and frame their witnesses’ opinions sympathetically rather than defensively.

Third, the plaintiffs had the good fortune of the defendant’s counsel’s apparent failure to find the key fallacies, invalidities, and flaws in plaintiffs’ questionable expert witness opinions.

The Allen case teaches that sometimes good lawyering can win a losing case.

The plaintiffs’ counsel retained and presented an array of expert witnesses who might be the usual suspects in a district court’s exclusion of expert witness testimony:

None of these four expert witnesses was a specialist in ALS or ALS causation; none was a neurologist; none had ever addressed ALS causation in a peer-reviewed article.  All four witnesses were frequent testifiers in tort litigation, and some have are repeat offenders when it comes to offering questionable or excludable opinion testimony.  Somehow, the defense dashed this opportunity by retaining only one expert, Dean M. Hashimoto, M.D., J.D., M.P.H., who was also not a specialist in ALS, who was not a neurologist, and who had never published anything on ALS.  And to make matters worse, the defense proceeded to challenge the plaintiffs’ expert witnesses for lack of qualifications!

The defense’s challenges to qualifications takes up a good deal of Judge Saylor’s published opinion, which illustrates the maxim that judges have short attention spans, and you should not waste the opportunity of a motion on an issue that is so easily decided against you.  The scientific issues are difficult and the temptation to avoid them is great.  By leading with an issue that will almost certainly lose, the defense wasted a valuable advocacy opportunity to show the court the fallacious reasoning in the plaintiffs’ case.  By submitting reports from only one expert witness, who had all the deficiencies claimed in the plaintiffs’ set of witnesses, the defense exhibited a duplicity that must have seriously undermined its credibility for the entire set of Rule 702 motion issues.


Dr. Christine Oliver has been testifying in asbestos and other occupational lung disease cases for decades.  She is a pulmonary physician on staff at Massachusetts General Hospital, in Boston, and an associate professor of clinical medicine at the Harvard Medical School.  She is board certified in internal medicine and in occupational medicine (American Board of Preventive Medicine), and her clinical interests are asthma occupational lung disease, and health hazards of construction work.  If the defense had presented real expert witnesses in ALS causation, Dr. Oliver’s expertise would have seemed quite irrelevant.  Dr. Oliver has, as well as I can determine, never researched or published on ALS causation.  She has, however, published on “multiple chemical sensitivity,” which should give a disinterested court some pause.  See L. Christine Oliver and Alison Johnson, “Multiple Chemical Sensitivity: Reflections” (Nov. 4, 2011).

Richard Clapp, professor emeritus at the Boston University School of Public Health, is a known purveyor of dubious courtroom testimony. See, e.g., Sutera v. The Perrier Group of America Inc., 986 F.Supp. 655 (D. Mass. 1997).  He is a frequent testifier and a charter member of the surreptitiously funded SKAPP organization.  Clapp is a non-physician epidemiologist, who has never published on ALS.

Marcia Ratner Ph.D. may be best known for her possession of mace and an unlicensed gun, but she does occasionally show up in civil litigation as an expert witness.  SeeQuincy District Court News,” Patriot Ledger June 09, 2010 (reporting that Ratner pleaded guilty to criminal possession of mace and a firearm).

Ratner is a postdoctoral researcher at Boston University, where she works as a neurotoxicologist.  She does not appear to have ever published a peer-reviewed paper on ALS or ALS causation.  Plaintiffs’ counsel claimed that she was researching a new drug with therapeutic potential for ALS treatment, although they were quite sketchy about details.  Ratner does not appear to hold any NIH grants for ALS drug research.

[Please see update on the discussion of Dr. Ratner at]

William Ewing, an industrial hygienist, frequently testifies in asbestos litigation.  He offered no opinion on causation.

Against this field of witnesses, the defense punted on presenting its own witness with relevant expertise. Dr. Dean M. Hashimoto, the defense’s sole witness on causation, is a physician, lawyer, and has a master’s degree in occupational health.  Hashimoto has no specialized training in ALS or clinical neurology, although he serves on the Massachusetts Workers’ Compensation Board. A pubmed search  shows that Hashimoto has never published on the neurology or causation of ALS.


The plaintiffs had a huge problem to avoid:  ALS has no known cause.  Counsel table could be filled up with textbooks and review articles, but perhaps the following, lengthy quote from the National Institute for Neurological Disorders and Stroke website suffices to make the point:

“What causes ALS?

The cause of ALS is not known, and scientists do not yet know why ALS strikes some people and not others. An important step toward answering that question came in 1993 when scientists supported by the National Institute of Neurological Disorders and Stroke (NINDS) discovered that mutations in the gene that produces the SOD1 enzyme were associated with some cases of familial ALS. This enzyme is a powerful antioxidant that protects the body from damage caused by free radicals. Free radicals are highly reactive molecules produced by cells during normal metabolism. If not neutralized, free radicals can accumulate and cause random damage to the DNA and proteins within cells. Although it is not yet clear how the SOD1 gene mutation leads to motor neuron degeneration, researchers have theorized that an accumulation of free radicals may result from the faulty functioning of this gene. In support of this, animal studies have shown that motor neuron degeneration and deficits in motor function accompany the presence of the SOD1 mutation.

Studies also have focused on the role of glutamate in motor neuron degeneration. Glutamate is one of the chemical messengers or neurotransmitters in the brain. Scientists have found that, compared to healthy people, ALS patients have higher levels of glutamate in the serum and spinal fluid. Laboratory studies have demonstrated that neurons begin to die off when they are exposed over long periods to excessive amounts of glutamate. Now, scientists are trying to understand what mechanisms lead to a buildup of unneeded glutamate in the spinal fluid and how this imbalance could contribute to the development of ALS.

Autoimmune responses—which occur when the body’s immune system attacks normal cells—have been suggested as one possible cause for motor neuron degeneration in ALS. Some scientists theorize that antibodies may directly or indirectly impair the function of motor neurons, interfering with the transmission of signals between the brain and muscles.

In searching for the cause of ALS, researchers have also studied environmental factors such as exposure to toxic or infectious agents. Other research has examined the possible role of dietary deficiency or trauma. However, as of yet, there is insufficient evidence to implicate these factors as causes of ALS.

Future research may show that many factors, including a genetic predisposition, are involved in the development of ALS.”

NINDS – “Amyotrophic Lateral Sclerosis (ALS) Fact Sheet.”

As a result, the plaintiffs adopted a strategy of confession and avoidance; they renounced any claim that they were asserting a causal claim.  Instead, they insisted that they were “merely” claiming that toluene exposure had accelerated the onset of sporadic ALS in Coach Allen.  This mere claim, however, was actually a causal claim in disguise, and the district judge was taken in by the ruse.  If plaintiffs were claiming that toluene can accelerate the onset of ALS by a meaningful period of time (years), then they were making a causal claim, legally and scientifically.  A shift in the age of onset of a sporadic disease is a causal claim, and it requires supporting evidence, not hand waving.


One scientist could postulate a reasonable mechanism even for a sporadic disease.  Professional journals and textbooks are filled with such speculation.  These postulations are part of science in that they inform research hypotheses and funding, but they are not conclusions of causality.  The quote above from the NINDS discusses the lack of an anti-oxidizing enzyme and glutamate toxicity as potential mechanisms in familial ALS, but even there, the authors are appropriately modest in avoiding a claim to know the pathogenesis of familial ALS.

The plaintiffs’ approach was to take the suggestion of a mechanism, misrepresent it as a known mechanism, and then claim that toluene activated glutamate toxicity and exercised an oxidizing effect on neurons. The plaintiffs’ team had no basis for claiming that short-term exposure to solvents, or toluene specifically, translated into a toxicity to the relevant human motor neurons that are involved in ALS.  It is a long stretch from suggesting a mechanism to documenting the mechanism to be actually at work in producing, or accelerating, a disease in humans.

A typical statement, from the Yale School of Medicine, Division of Neurology, in 2012:

Why the motor neurons begin to die is still unknown. Recent evidence, however, have implicated glutamate excitotoxicity, free radical toxicity, and mitochondrial dysfunction as possible mechanisms, and this is an area of active research.”

Amyotrophic Lateral Sclerosis (ALS)” (emphasis added).   See also Adams and Victor’s Principles of Neurology 1157-58 (7th ed. 2001) (noting that the pathogenesis of ALS and similar motor neuron diseases is not known).

The district judge seemed mesmerized by Ratner’s having providing a biologically plausible theory for tying ALS progression to toluene exposure.  263 F.R.D. at 60.  Judge Saylor stated that the defense did not address any flaw in Ratner’s methodology other than to point out that her theory was not supported by epidemiology.  The court seemed to equate providing a plausible theory with establishing a scientific conclusion.  More to the point, the court was truly asleep at its gatekeeping task because Ratner’s theory actually presupposed that she knew that Coach Allen was going to develop ALS in any event, only not as early as 2001.  The court faulted the defense for not showing that Ratner’s (and the other plaintiffs’ witnesses’) theory was unreliable, but the burden was on the plaintiffs to show reliability.  Id.  The court not only faulted the defense for carrying a burden it did not have, but it overlooked the very telling criticisms of Ratner’s theories of acceleration and mechanism.


Plaintiffs’ expert witnesses had a welter of excuses as to why there was no epidemiologic data to support their theories.  The absence of statistical significance, according to plaintiffs’ expert witnesses does not mean that a study should be disregarded.  Id. at 58.  Their claim is superficially true, but a study not disregarded does not necessarily support a causal inference, either alone or conjunction with other such studies. Similarly, plaintiffs’ claim that flawed studies should not be disregarded is also a half truth.  A flawed study may lead to a much better one, which can support valid inferences.  Flawed studies are thus part of the scientific process because they may lead to a self-correcting triangulation of the truth, but there is little to recommend relying upon flawed studies to support scientific conclusions of causality.  Nevertheless, the district court appeared to swallow these half truths, whole.

Ratner also advanced a claim that the acceleration theory had not been subjected to epidemiologic analysis because of “funding limitations, as most funding goes toward finding treatment or cures for the disease, not towards finding what accelerates the course of the disease.”  Id. at 59 n. 14.  The district court repeats this excuse without critical thought.  If a commonly used solvent such as toluene accelerated the onset of a terrible disease such as ALS by decades, such a putative effect would be amenable to epidemiologic analysis and would be a source of incredible concern and funding efforts by the NIH, NINDS, NIEHS, and other granting agencies and organizations.  Despite excusifying verbiage, Ratner maintained that there were no epidemiologic data that refuted her novel acceleration.  Id. at 59.  Of course, if her excuses were taken seriously, then this absence of refutation was fairly irrelevant, but in any event, this supposed absence could not support the reliability of Ratner’s inferences or conclusions.

The defense focused on the lack of short-term exposures in epidemiologic studies, and also the lack of statistical significance in some studies.  What appears to have been missing from both sides was a comprehensive analysis of the available epidemiologic data.  If long-term exposure were associated with earlier age of onset of ALS, or even a greater risk of ALS, then it would have given some support to Ratner’s novel theory.  The defense appeared to punt on the epidemiology by claiming its irrelevance.  It might have been helpful to point out internal as well as external validity issues to the court.

As for both sides citing different studies, and no side presenting a comprehensive view of the epidemiologic evidence, the court could have given some consideration to the ethical considerations of the incomplete presentation:

“Basis of Expert Medical Testimony

The testimony of an expert medical witness should be founded on a thorough and critical review of the pertinent medical and scientific facts, available data, and relevant literature.”

Ethical Guidelines for Occupational and Environmental Medicine Physicians Serving as Expert Witnesses (Oct. 25, 2007).


The plaintiffs’ claim that they were not asserting causation was disingenuous.  As noted above, acceleration of onset is a form of causation.  Of course, exposure to a neurotoxic material, with some symptoms, might have made Allen more aware of other symptoms, and so the time to diagnosis was abbreviated.  The plaintiffs, however, were claiming more than earlier ascertainment; they claimed the toluene exposure caused an underlying disease process to accelerate.

Oliver actually went further and performed an invalid differential etiologic analysis. Oliver reviewed medical records and claimed to have applied “differential diagnosis to the review.”  Id. at 63. This claim was quite bogus because there was no dispute that Allen had and died of ALS, but the district court was beguiled.  Having ruled out family history, Oliver claimed to then rule out other “putative causes” of ALS:  “pesticides and agricultural chemicals containing solvents, 60-hertz magnetic fields, and welding fumes.”  Id. at 63.  In one fell swoop, Oliver created several known causes to be ruled out, and then ruled them out in Allen’s case.  This is remarkable given that NINDS and most of medical sciences does not recognize any known or putative causes of sporadic ALS, and that Oliver failed to rule out the one potential cause that some scientists take seriously:  cigarette smoking.  See, e.g., Hao Wang, Éilis J. O’Reilly, Marc G. Weisskopf, Giancarlo Logroscino, Marji L. McCullough, Michael Thun, Arthur Schatzkin, Laurence N. Kolonel, Alberto Ascherio, “Smoking and risk of amyotrophic lateral sclerosis: a pooled analysis of 5 prospective cohorts” 68 Arch. Neurol. 207 (2011); A. Alonso, G. Logroscino, M.A. Hernán, “Smoking and the risk of amyotrophic lateral sclerosis: a systematic review and meta-analysis,” 81 J. Neurol. Neurosurg. & Psychiatry 1249 (2010); F. Fang & W. Ye, “Smoking may be considered an established risk factor for sporadic ALS,” 74 Neurology 1927 (2010).

Of course, Oliver, and the entire plaintiffs’ expert witness team failed to rule out the most obvious, most prevalent explanation for Allen’s ALS:  unknown.


Ratner testified “to a reasonable degree of scientific certainty that Allen was genetically predisposed to develop ALS and would have developed and died from ALS later in his life.”  263 F.R.D. at 61.  This assertion was truly an incredible, unsupported, unverifiable, and unfalsifiable statement.  If a drug company ever made a similarly unsupported claim in an electronically transmitted document, the Department of Justice would prosecute it for wire fraud.  United States v. Harkonen, 2010 WL 2985257 (N.D. Calif. 2010).

The parties had essentially stipulated that Allen did not suffer from familial ALS, and neither Ratner nor anyone else identified any gene that was responsible for his “susceptibility.”  The district court, of course, did not report how Ratner could possibly have known that Allen was going to develop ALS, only at some unspecified date later than the date when Allen first became aware of signs and symptoms of motor neuron disease.  The district court announced that plaintiffs’ expert witnesses were not propounding “junk science,” but perhaps the heavy perfume helped masquerade the garbage.


The court conclusorily noted, without explanation, that the temporal relationship between exposure and disease manifestation would allow a conclusion of causality:

“Finally, after interpreting the data within a chronological context, the clinician may conclude that the patient’s disease is a neurotoxic illness.”

Id. at 61.  The court appears to accept the temporal pattern as sufficient in itself, or with other information, to support the conclusion.  This reasoning is fallacious.


Allen developed ALS when he was 45 years old.  Ratner reasoned that the average age of onset was 60, and Allen developed his disease “much earlier than would be expected”; therefore toluene accelerated the onset of Allen’s disease.  Id. at 61. The problem is that there is no “therefore” that can reasonably be claimed in the court’s sentence.

Most publications put the mean and median of age of ALS onset around 55 years, but even if the court were to accept Ratner’s reference to 60 as correct, surely the court recognized that half the cases therefore occurred below the age of 60.  The question of course is the variability in age of onset, and the court’s opinion is silent about the scatter or distribution of age-of-onset data.  Ratner’s reasoning was prima facie invalid unless there was additional information to show a very narrow distribution of age of onset around the mean.  It is difficult to discern whether the defense made this point, but Ratner could not have supported this counterfactual claim.

Here is what the ALS association has to say about the issue:

“Most people who develop ALS are between the ages of 40 and 70, with an average age of 55 at the time of diagnosis. However, cases of the disease do occur in persons in their twenties and thirties.”

Who Gets ALS.”

Ratner essentially conceded that her argument was vacuous and invalid.  When confronted at her deposition about whether age of onset greater than the mean would have changed her opinion, she emphatically denied its relevance:

“My opinion would be the same even if that guy died at 60 instead of 75 and had history of this exposure … but you wouldn’t have bothered to depose me in that case… . Somebody else has moved down from where they are to here. But it may not result in a lawsuit, and I wouldn’t be here, because— I wouldn’t be here.”

Ratner Deposition at 172-3.


The district court recognized the novelty of Ratner’s analysis, but opined that Ratner, Oliver, and Clapp had provided sufficient cumulative evidence to support their theories.  263 F.R.D. at 61.  The trial court apparently conducted a Rule 702 hearing, over three days. Both sides filed what appears to have been extensive briefing and affidavits.  There are some huge gaps in the reasoning of the plaintiffs’ expert witnesses, and in the district court’s opinion.  Perhaps those gaps could be filled in with volumes of testimony.  My unscientific opinion is to doubt it. Although the plaintiffs should have had the burden of showing admissibility, the defendant had the practical burden of illustrating the analytical gaps, ipse dixit, fallacies, and invalid inferences that were before the court.  The defense may have indeed pointed out such problems, which were fulsomely present, but the district court’s opinion does not report the obvious defense arguments.  Without more background information, it is difficult to evaluate comprehensively the court’s or the defense’s handling of the scientific issues that were clearly before the court on the Rule 702 motions.  What is clear from what the district court reports is, however, sufficient to document an unsatisfactory judicial review of the evidence discussed.

General Causation and Epidemiologic Measures of Risk Size

November 24th, 2012

The gatekeeper’s door really must swing both ways on causal analysis. For decades, the courts allowed anything as long as the speaker was “an expert witness,” who uttered the magic words “reasonable medical certainty.”  For the most part, this willingness to tolerate all sorts of nonsense favored plaintiffs.  In the backlash against this judicial libertine approach, some courts, such as those in Texas, have embraced a principle that unfairly favors defendants.  Abridgment of scientific method and reasoning is offensive regardless who is being favored.

The Texas courts have adopted a rule that plaintiffs must offer a statistically significant study, with a risk ratio (RR) greater than two, to show general causation.  A RR ≤ 2 can be a strong practical argument against specific causation in many cases. See Courts and Commentators on Relative Risks to Infer Specific CausationRelative Risks and Individual Causal Attribution; and  Risk and Causation in the Law.   But a RR > 2 threshold has little in theory to do with general causation.  There are any number of well-established causal relationships, where the magnitude of the ex ante risk in an exposed population is > 1, but ≤ 2.  The magnitude of risk for cardiovascular disease and smoking is one such well-known example.  As I noted in “Confusion Over Causation in Texas” (Aug. 27, 2011), the Texas Supreme Court managed to confuse general and specific causation concepts in its decision in Merck & Co. v. Garza, 347 S.W.3d 256 (2011).

Still, the search for a RR threshold for general causation does have some basis in the practice of epidemiology. When assessing general causation from only observational epidemiologic studies, where residual confounding and bias may be lurking, it is prudent to require a RR > 2, as a measure of strength of the association that can help us rule out the role of systemic error.  As the cardiovascular disease/smoking example illustrates, however, there is clearly no scientific requirement that the RR be greater than 2 to establish general causation.  Courts should recognize that there are spurious associations with RR >> 2, and true, causal associations with RR < 2. Much will depend upon the number of studies, and the potential for bias or confounding in the body of evidence.  If the other important Bradford Hill factors are present – dose-response, consistent, coherence, etc. – then risk ratios ≤ 2, from observational studies, may suffice to show general causation.  So a requirement of RR > 2, for the showing of general causation, does not make sense as a criterion for general causation; and at best, RR > 2 is a much weaker consideration for general causation than it is for specific causation.

Randomization and double blinding are major steps in controlling confounding and bias, but they are not guarantees that systematic bias has been eliminated.  Similarly, despite the confusion and errors of lawyers and judges, statistical significance does not address bias or confounding.  See, e.g., Zach Hughes, “The Legal Significance of Statistical Significance,” 28 Westlaw Journal: Pharmaceutical 1, 2 (Mar. 2012) (erroneously describing the meaning and function of significance testing; “Stated simply, a statistically significant confidence interval helps ensure that the findings of a particular study are not due to chance or some other confounding factors.”).

A double-blinded, placebo-controlled, randomized clinical trial (RCT) will usually have less opportunity for bias and confounding to play a role.  Imposing a RR > 2 requirement for general causation thus makes less sense in the context of trying to infer general causation from the results of RCTs. The Garza Court, however, went a dictum too far by describing RR > 2 as a requirement that applied to general causation:

Havner holds, and we reiterate, that when parties attempt to prove general causation using epidemiological evidence, a threshold requirement of reliability is that the evidence demonstrate a statistically significant doubling of the risk. In addition, Havner requires that a plaintiff show ‘that he or she is similar to [the subjects] in the studies’ and that ‘other plausible causes of the injury or condition that could be negated [are excluded] with reasonable certainty’.40

347 S.W.3d at 265 (quoting from Merrell Dow Pharmaceuticals, Inc. v. Havner, 953 S.W.2d 706, 720 (Tex. 1997).  See Merk’s Appellant’s Brief to the Texas Court of Appeals at 16, 17 (July 16, 2007) (citing the Havner case as providing a “rational basis for inferring causation”; “To prove general causation, the Garzas were required to introduce at least two statistically significant scientific studies showing that Vioxx at the same dose and duration as taken by Mr. Garza more than doubled the risk of heart attack. Havner, 953 S.W.2d at 718-23, 727.”).

Imposing RR > 2 as a requirement for general causation, in the context of risk ratios from clinical trials, was particularly unwarranted. If general causation were the issue, it would be difficult to make out a reason for why the dose and duration used in the study had to be the same as that used by the specific plaintiff. General causation was not the dispositive issue in Garza, and so this language should be treated as dictum.  The confusion between general and specific causation is unfortunate.

What is the source of the Garza court’s notion about RR and general causation?  One popular article from Science, in the 1990’s, gave some credence to the notion of a minimal RR for general causation. Gary Taubes, “Epidemiology Faces Its Limits,” 269 Science 164 (July 14, 1995) [cited as Taubes]. Taubes collected quotes (or sound bites) from various authors, about the relevance of the magnitude of observed associations.  For instance, Taubes quoted Marcia Angell, a former editor of the New England Journal of Medicine, as articulating a general rule:

“As a general rule of thumb, we are looking for a relative risk of 3 or more [before accepting a paper for publication], particularly if it is biologically implausible or if it’s a brand new finding.”

Taubes at 168.  John Bailar, a professor emeritus at the University of Chicago, was quoted by Taubes as rejecting any reliable dividing line, thus taking a more nuanced approach:

“If you see a 10-fold relative risk and it’s replicated and it’s a good study with biological backup, like we have with cigarettes and lung cancer, you can draw a strong inference. * *  * If it’s a 1.5 relative risk, and it’s only one study and even a very good one, you scratch your chin and say maybe.”

Taubes at 168. Taubes described Harvard epidemiologist Dimitrios Trichopoulos as suggesting that a study should show a four-fold increased risk, and the late Sir Richard Doll of Oxford University as suggesting that a single epidemiologic study would not be persuasive unless the lower limit of its 95% confidence interval exclude 3.0.  Id.

Even if Taubes’ quotes are accurate, there is a risk that they were stripped of important nuance provided by the scientists he interviewed.  There are other, more credible sources, however, for scientists who have insisted on a need to use the size of a RR as a consideration in evaluating the causality of an association, especially for observational studies.  For example, Breslow and Day, two respected cancer researchers, noted in a publication of the World Health Organization, that

“[r]elative risks of less than 2.0 may readily reflect some unperceived bias or confounding factor, those over 5.0 are unlikely to do so.”

Norman E. Breslow & Nicholas E. Day, Statistical Methods in Cancer Research. Volume I The Analysis of Case-Control Studies at 36 (Lyon, International Agency for Research on Cancer Scientific Publications No. 32, 1980).  The caveat makes sense, but it clearly was never intended to be some sort of bright-line rule for people too lazy to look at the actual studies and data.  Unfortunately, not all epidemiologists are as capable as Breslow and Day, and there are plenty of examples of spurious RR > 5, arising from biased or confounded studies.

Sir Richard Doll, and Sir Richard Peto, expressed a similarly skeptical view about RR < 2, in assessing the causality of associations:

“when relative risk lies between 1 and 2 … problems of interpretation may become acute, and it may be extremely difficult to disentangle the various contributions of biased information, confounding of two or more factors, and cause and effect.”

Richard Doll & Richard Peto, The Causes of Cancer 1219 (Oxford Univ. Press 1981).

More recently, plaintiffs’ testifying expert witness, David Goldsmith expressed the view that a RR > 2 is a minimal indication of a strong RR, which is a likely candidate for causality. David F. Goldsmith & Susan G. Rose, “Establishing Causation with Epidemiology,” in Tee L. Guidotti & Susan G. Rose, eds., Science on the Witness Stand:  Evaluating Scientific Evidence in Law, Adjudication, and Policy 57, 60 (OEM Press 2001) (“There is no clear consensus in the epidemiology community regarding what constitutes a ‘strong’ relative risk, although, at a minimum, it is likely to be one where the RR is greater than two; i.e., one in which the risk among the exposed is at least twice as great as among the unexposed.”); Ernst L. Wynder & Geoffrey C. Kabat, “Environmental Tobacco Smoke and Lung Cancer: A Critical Assessment,” in H. Kasuga, ed., Indoor Air Quality 5, 6 (Berlin Springer Verlag, 1990) (“An association is generally considered weak if the odds ratio is under 3.0 and particularly when it is under 2.0, as is the case in the relationship of ETS and lung cancer. If the observed relative risk is small, it is important to determine whether the effect could be due to biased selection of subjects, confounding, biased reporting, or anomalies of particular subgroups.”).

In the 1990’s, Dr. Janet Daling and her colleagues published an observational epidemiologic study on whether abortion was related to later breast cancer. Janet R. Daling, K.E. Malone, L.F. Voigt, E. White, Noel S. Weiss, “Risk of breast cancer among young women: relationship to induced abortion,” 86 J. Nat’l Cancer Instit. 1584 (1994). Several scientists, concerned that Dr. Daling’s findings would be distorted by religious propagandists, wrote that the small RRs in the Daling study could not support a causal interpretation of the data.  In an editorial that accompanied the article, Dr. Lynn Rosenberg, of the Boston University School of Medicine, wrote:

“A typical difference in risk (50%) is small in epidemiologic terms and severely challenges our ability to distinguish if it reflects cause and effect or if it simply reflects bias.”

Lynn Rosenberg, “Induced Abortion and Breast Cancer: More Scientific Data Are Needed,” 86 J. Nat’l Cancer Instit. 1569, 1569 (1994).  Rosenberg’s caution was picked up and repeated by an official statement of the National Cancer Institute (NCI).  Linda Anderson, of the NCI Press Office (NIH) issued a press release to stifle fears raised by Dr. Daling’s abortion research:

“In epidemiologic research, relative risks of less than 2 are considered small and are usually difficult to interpret. Such increases may be due to chance, statistical bias, or effects of confounding factors that are sometimes not evident.”

Linda Anderson, “Abortion and possible risk for breast cancer: analysis and inconsistencies,” (Wash. DC, NCI Oct. 26. 1994).  In the lay media, an American Cancer Society epidemiologist was quoted in reference to the Daling study:

“Epidemiological studies, in general are probably not able, realistically, to identify with any confidence any relative risks lower than 1.3 (that is a 30% increase in risk) in that context, the 1.5 [reported relative risk of developing breast cancer after abortion] is a modest elevation compared to some other risk factors that we know cause disease.”

Washington Post (Oct 27,1994) (Dr. Eugenia Calle, Director of Analytic Epidemiology for the ACS).

Not surprisingly, tobacco companies, embattled by claims of cancer from environmental tobacco smoke (ETS) cried political correctness when the NCI and the ACS announced a skeptical view of whether RRs between 1 and 2 could show a causal relationship between abortion and breast cancer, while endorsing a low RR as real in the case of ETS and lung cancer.

What the tobacconists, however, missed was that Daling’s association was a relatively novel finding.  Subsequent studies failed to corroborate the association, which now lives on only because of the efforts of theocratic regimes in some of the United States.  The NCI’s reaction to the Daling study was in line with the quotes from Taubes’ article, above.

Recently, two epidemiologists reviewed the issue of minimal reliable risk, and concluded:

“There is no single number for a minimal reliable risk that pertains to all studies.”

Mark J. Nicolich and John F. Gamble, “What is the Minimum Risk that can be Estimated from an Epidemiology Study?,” in Anca Moldoveanu, ed., Advanced Topics in Environmental Health and Air Pollution Case Studies,at 4.1.1 Point 1 (2011).   Of course, this pronouncement by Nicolich and Gamble is precisely the sort of call for sound judgment that lawyers fear because it involves engagement with the studies, their methods, and their data. The potential for bias and confounding is not constant across all studies.  The potential for such errors varies with the nature of the exposure and the outcome under investigation, the design of the study, and myriad particulars and details of the studies involved.  As Nicolich and Gamble explained:

“Theoretically, there is no relative risk that is too small to be estimated. The relative risk is a construct or a concept, not a physical reality. Since it is a mathematically defined concept it can be mathematically estimated to any degree of precision. However, we have shown in this paper that (1) there are many assumptions that must be met to make certain that the RR estimate is accurate and precise; and (2) the significance level or uncertainty associated with the RR estimate has its own set of assumptions that must be met. So, while there may be no theoretical minimum RR that can be estimated, in practice there is a minimum risk and varies depending on uncertainties present in the context of each study.

An analogy in the physical world of estimating a RR is to measure the length of an object. A meterstick is precise enough to determine the width of a table to see if it will fit through a doorway, but a meterstick is not precise enough to measure the diameter of a shaft in an automobile engine with a tolerance of ±1.0 mm. To measure the shaft diameter one would use a micrometer. The micrometer while sufficiently precise to measure the shaft is not adequate to determine the size of a dust mite, usually in the range of 200 to 300 μm. The analogy can be carried through to the size of molecules, to the wavelength of visible light, and to the diameter of an electron. The conclusion is that while all the tasks involve measuring length and there is no practical ‘minimum length’, different tools and considerations are needed depending on the object to be measured and the precision required.”

Id. at 21.

“We agree with Wynder (1987) that epidemiology is able to correctly interpret relatively small relative risks, but only if the best epidemiological methodology is applied and only if the data are fully evaluated by examining all judgment criteria, especially those of biological plausibility. As RRs become smaller, the need for close adherence to these basic principles becomes greater. If these ideas are applied, a conclusion of no risk should reassure society. And when a risk is reported as positive, appropriate preventive measures to reduce avoidable illness can be used to successfully reach the ultimate goal of epidemiology and preventive medicine.”

Id. at 22.

Nicolich and Gamble probably provide more nuance than most courts want, but it is what scientists, policy makers, and lawyers need to hear. Simplistic rules, such as a requirement of two statistically significant studies with RR > 2, do not enhance the credibility of judicial judgments. The requirement is over- and under-inclusive; it screens out real causal associations while allowing spurious associations, almost certainly the product of bias or confounding, to stand.

Wells v. Ortho Pharmaceutical Corp. Reconsidered – Part 6

November 21st, 2012

In 1984, before Judge Shoob gave his verdict in the Wells case, another firm filed a birth defects case against Ortho for failure to warn in connection with its non-ionic surfactant spermicides, in the same federal district court, the Northern District of Georgia. The mother in Smith used Ortho’s product about the same time as the mother in Wells (in 1980).  The case was assigned to Judge Shoob, who recused himself.  Smith v. Ortho Pharmaceutical Corp., 770 F. Supp. 1561, 1562 n.1 (N.D. Ga. 1991) (no reasons for the recusal provided).  The Smith case was reassigned to Judge Horace Ward, who entertained Ortho’s motion for summary judgment in July 1988.  Two and one-half years later, Judge Ward granted summary judgment to Ortho on grounds that the plaintiffs’ expert witnesses’ testimony was not based upon the type of data reasonably relied upon by experts in the field, and was thus inadmissible under Federal Rule of Evidence 703. 770 F. Supp. at 1681.

A prevalent interpretation of the split between Wells and Smith is that the scientific evidence developed with new studies, and that the scientific community’s views matured in the five years between the two district court opinions. The discussion in Modern Scientific Evidence is typical:

“As epidemiological evidence develops over time, courts may change their view as to whether testimony based on other evidence is admissible. In this regard it is worth comparing Wells v. Ortho Pharmaceutical Corp., 788 F.2d 741 (11th Cir. 1986), with Smith v. Ortho Pharmaceutical Corp., 770 F. Supp. 1561 (N.D. Ga. 1991). Both involve allegations that the use of spermicide caused a birth defect. At the time of the Wells case there was limited epidemiological evidence and this type of claim was relatively novel.  In a bench trial the court found for the plaintiff.  *** The Smith court, writing five years later, noted that, ‘The issue of causation with respect to spermicide and birth defects has been extensively researched since the Wells decision.’ Smith v. Ortho Pharmaceutical Corp., 770 F. Supp. 1561, 1563 (N.D. Ga. 1991).”

1 David L. Faigman, Michael J. Saks, Joseph Sanders, and Edward K. Cheng, Modern Scientific Evidence:  The Law and Science of Expert Testimony, “Chapter 23 – Epidemiology,” § 23:4, at 213 n.12 (West 2011) (internal citations omitted).

Although Judge Ward was being charitable to his judicial colleague, this attempt to reconcile Wells and Smith does a disservice to Judge Ward’s hard work in Smith, and Judge Shoob’s errors in Wells.

Even a casual reading of Smith and Wells reveals that the injuries were completely differently.  Plaintiff Crystal Smith was born with a chromosomal defect known as Trisomy-18; Plaintiff Katie Wells was born with limb reduction deficits.   Some studies relevant to one injury had no information about the other.  Other studies, which addressed both injuries, yielded different results for the different injuries.  Although some additional studies were available to Judge Ward in 1988, this difference is hardly the compelling difference between the two cases.

Perhaps the most important difference between the cases is that in Smith, the biologically plausibility that spermicides could cause a Trisomy-18 was completely absent.  The chromosomal defect arises from a meiotic disjunction, an error in meiosis that is part of the process in which germ cells are formed.  Simply put, spermicides arrive on the scene too late to cause a Trisomy-18.  Notwithstanding the profound differences between the injuries involved in Wells and Smith, the Smith plaintiffs sought the application of collateral estoppel.  Judge Ward refused this motion, on the basis of the factual differences in the cases, as well as the availability of new evidence.  770 F.Supp. at 1562.

The difference in injuries, however, was not the only important difference between these two cases.  Wells was actually tried, apparently without any challenge under Frye, or Rules 702 or 703, to the admissibility of expert witness testimony.  There is little to no discussion of scientific validity of studies, or analysis of the requisites for evaluating associations for causality.  It is difficult to escape the conclusion that Judge Shoob decided the Wells case on the basis of superficial appearances, and that he frequently ignored validity concerns in drawing invidious distinctions between plaintiffs’ and defendant’s expert witnesses and their “credibility.”  Smith, on the other hand, was never tried.  Judge Ward entertained and granted dispositive motions for summary judgment, on grounds that the plaintiffs’ expert witnesses’ testimony was inadmissible. Legally, the cases are light years apart.

In Smith, Judge Ward evaluated the same FDA reports and decisions seen by Judge Shoob.  Judge Ward did not, however, dismiss these agency materials simply because one or two of dozens of independent scientists involved had some fleeting connection with industry. 770 F.Supp. at 1563-64.

Judge Ward engaged with the structure and bases of the expert witnesses’ opinions, under Rules 702 and 703.  The Smith case thus turned on whether expert witness opinions were admissible, an issue not considered or discussed in Wells.  As was often the case before the Supreme Court decided Daubert in 1993, Judge Ward paid little attention to Rule 702’s requirement of helpfulness or knowledge.  The court’s 702 analysis was limited to qualifications.  Id. at 1566-67.  The qualifications of the plaintiffs’ witnesses were rather marginal.  They relied upon genetic and epidemiologic studies, but they had little training or experience in these disciplines. Finding the plaintiffs’ expert witnesses to meet the low threshold for qualification to offer an opinion in court, Judge Ward focused on Rule 703’s requirement that expert witnesses reasonably rely upon facts and data that are not otherwise admissible.

The trial court in Smith struggled with how it should analyze the underpinnings of plaintiffs’ witnesses’ proffered testimony.  The court acknowledged that conflicts between expert witnesses typically raise questions of weight, not admissibility.  Id. at 1569.  Ortho had, however, challenged plaintiffs’ witnesses for having given opinions that lacked a “sound underlying methodology.” Id.  The trial court found at least one Fifth Circuit case that suggested that Rule 703 requires trial courts to evaluate the reliability of expert witnesses’ sources.  Id. (citing Soden v. Freightliner Corp., 714 F.2d 498, 505 (5th Cir. 1983). Elsewhere, the trial court also found precedent from Judge Weinstein’s opinion in Agent Orange, as well as Court of Appeals decisions involving Bendectin, all of which turned to Rule 703 as the legal basis for reviewing, and in some cases limiting or excluding expert witness opinion testimony.  Id.

The defendant’s argument under Rule 703 was strained; Ortho argued that the plaintiffs’

“experts’ selection and use of the epidemiological data is faulty and thus provides an insufficient basis upon which experts in the field of diagnosing the source of birth defects normally form their opinions. The defendant also contends that the plaintiffs’ experts’ data on genetics is not of the kind reasonably relied upon by experts in field of determining causation of birth defects.”

Id. at 1572.  Nothing in Rule 703 addresses the completeness or thoroughness of expert witnesses in their consideration of facts and data; nor does Rule 703 address the sufficiency of data or the validity vel non of inferences drawn from facts and data considered.  Nonetheless, the trial court in Smith took Rule 703 as its legal basis for exploring the epistemic warrant for plaintiffs’ witnesses’ causation opinions.

Although plaintiffs’ expert witnesses stated that they had relied upon epidemiologic studies and method, the trial court in Smith went beyond their asseverations.  The Smith trial court explored the credibility of these witnesses at a whole other level.  The court reviewed and discussed the basic structure of epidemiologic studies, and noted that the objective of such studies is to provide a statistical analysis:

“The objective of both case-control and cohort studies is to determine whether the difference observed in the two groups, if any, is ‘statistically significant’, (that is whether the difference found in the particular study did not occur by chance alone).40 However, statistical methods alone, or the finding of a statistically significant association in one study, do not establish a causal relationship.41 As one authority states:

‘Statistical methods alone cannot establish proof of a causal relationship in an association’.42

As a result, once a statistical association is found in an epidemiological study, that data must then be evaluated in a systematic manner to determine causation. If such an association is present, then the researcher looks for ‘bias’ in the study.  Bias refers to the existence of factors in the design of a study or in the manner in which the study was carried out which might distort the result.43

If a statistically significant association is found and there is no apparent ‘bias’, an inference is created that there may be a cause-and-effect relationship between the agent and the medical effect. To confirm or rebut that inference, an epidemiologist must apply five criteria in making judgments as to whether the associations found reflect a cause-and-effect relationship.44 The five criteria are:

1. The consistency of the association;

2. The strength of the association;

3. The specificity of the association;

4. The temporal relationship of the association; and,

5. The coherence of the association.

Assuming there is some statistical association, it is these five criteria that provide the generally accepted method of establishing causation between drugs or chemicals and birth defects.45

The Smith court acknowledged that there were differences of opinion in weighting these five factors, but that some of them were very important to drawing a reliable inference of causality.  Id. at 1775.

A major paradigm shift thus separates Wells and Smith.  The trial court in Wells contented itself with superficial and subjective indicia of witnesses’ personal credibility; the trial in Smith delved into the methodology of drawing an appropriate scientific conclusion about causation.  Telling was the Smith court’s citation to Moultrie v. Martin, 690 F.2d 1078, 1082 (4th Cir. 1982) (“In borrowing from another discipline. a litigant cannot be selective in which principles are applied.”).  770 F.Supp. at 1575 & n.45.  Gone is the Wells retreat from engagement with science, and the dodge that the court must make a legal, not a scientific decision.

Applying the relevant principles, the Smith court found that the plaintiffs’ expert witnesses had deviated from the scientific standards of reasoning and analysis:

“It is apparent to the court that the testimony of Doctors Bussey and Holbrook is insufficiently grounded in any reliable evidence. * * * The conclusions Doctors Bussey and Holbrook reach are also insufficient as a basis for a finding of causality because they fail to consider critical information, such as the most relevant epidemiologic studies and the other possible causes of disease.81

The court finds that the opinions of plaintiffs’ experts are not based upon the type of data reasonably relied upon by experts in determining the cause of birth defects. Experts in determining birth defects rely upon a consensus in genetic or epidemiological investigations or specific generally accepted studies in these fields. While a consensus in genetics or epidemiology is not a prerequisite to a finding of causation in any and all birth defect cases, Rule 703 requires some reliable evidence for the basis of an expert’s opinion.

Experts in determining birth defects also utilize methodologies and protocols not followed by plaintiffs’ experts. Without a well-founded methodology, opinions which run contrary to the consensus of the scientific community and are not supported by any reliable data are necessarily speculative and lacking in the type of foundation necessary to be admissible.

For the foregoing reasons, the court finds that plaintiffs have failed to produce admissible evidence sufficient to show that defendant’s product caused Crystal’s birth defects.”

Id. at 1581.  Rule 703 was forced into a service to filter out methodologically specious opinions.

Not all was smooth sailing for Judge Ward.  Like Judge Shoob, Judge Ward seemed to think that a physical examination of the plaintiff provided helpful, relevant evidence, but he never articulated what the basis for this opinion was. (His Honor did note that the parties agreed that the physical examination offered no probative evidence about causation.  Id. at 1572 n.32.) No harm came of this opinion.  Judge Ward wrestled with the lack of peer review in some unpublished studies, and the existence of a study only in abstract form.  See, e.g., id. at 1579 (“a scientific study not subject to peer review has little probative value”); id. at 1578 (insightfully noting that an abstract had insufficient data to permit a reader to evaluate its conclusions).  The Smith court recognized the importance of statistical analysis, but it confused Bayesian posterior probabilities with significance probabilities:

“Because epidemiology involves evidence on causation derived from group based information, rather than specific conclusions regarding causation in an individual case, epidemiology will not conclusively prove or disprove that an agent or chemical causes a particular birth defect. Instead, its probative value lies in the statistical likelihood of a specific agent causing a specific defect. If the statistical likelihood is negligible, it establishes a reasonable degree of medical certainty that there is no cause-and-effect relationship absent some other evidence.”

The confusion here is hardly unique, but ultimately it did not prevent Judge Ward from reaching a sound result in Smith.

What intervened between Wells and Smith was not any major change in the scientific evidence on spermicides and birth defects; the sea change came in the form of judicial attitudes toward the judge’s role in evaluating expert witness opinion testimony.  In 1986, for instance, after the Court of Appeals affirmed the judgment in Wells, Judge Higginbotham, speaking for a panel of the Fifth Circuit, declared:

“Our message to our able trial colleagues: it is time to take hold of expert testimony in federal trials.”

 In re Air Crash Disaster at New Orleans, 795 F.2d 1230, 1234 (5th Cir. 1986).  By the time the motion for summary judgment in Smith was decided, that time had come.

Wells v. Ortho Pharmaceutical Corp. Reconsidered – Part 5

November 21st, 2012

While the trial court was preparing its findings of fact and conclusions of law, Ortho moved to reopen to evidence to permit additional testimony based upon three new articles.  Ortho’s motion came three months after the close of evidence, and Judge Shoob’s announcement of his verdict. The court denied this motion without mentioning what the new articles purported to show.  Wells v. Ortho Pharmaceutical Corp., 615 F. Supp. 262, 298 (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).

What is remarkable in Wells, from the vantage point of current practice, is the absence of motions directed at the proffered expert witness opinion testimony.  On the basis of Judge Shoob’s opinion, there appears to have been no Frye motion, no motions to exclude expert witnesses based upon the Federal Rules of Evidence, and no motions to strike testimony after the fact for lack of a proper basis.

Having lost the verdict in a bench trial, Ortho had little chance for success in the Court of Appeals on a claim that the evidence supporting the plaintiffs’ verdict was legally insufficient.  The traditional standard, applied by the Court of Appeals, was to sustain the trier of fact’s decision as not “clearly erroneous” when there were two “permissible” views of the evidence. 788 F.2d 741, 743 (11th Cir. 1986).  Without some legal doctrine to filter out flawed, invalid, and inadequate expert witness opinion from permissible views of an evidentiary display, the Court of Appeals was left with only a rubber stamp, which it proceeded to use with alacrity.

Ortho attempted to turn its appellate argument about the sufficiency of the evidence into a legal principle about rejecting factual findings not based upon “scientifically reliable foundations.”  Id. at 744.  The appellate court framed the issue on appeal simply as a “battle of the experts,” which Ortho had lost.  Both sides had qualified expert witnesses, and thus, according to the appellate court, “the district court was forced to make credibility determinations to ‘decide the victor’.” Id. (citing Ferebee v. Chevron Chemical Co., 736 F.2d 1529, 1535 (D.C. Cir.), cert. denied, 469 U.S. 1062 (1984)).  The Court of Appeals thus acquiesced in Judge Shoob’s superficial analysis, which attempted to resolve a scientific issue by trial atmospherics, demeanor, and subjective impressions of witness confidence rather than the validity of the studies relied upon and inferences drawn therefrom.  The possibility that Judge Shoob might have evaluated the evidentiary basis underlying the expert witnesses’ opinions was not even acknowledged.

The Court of Appeals invoked the language from Ferebee on statistical significance, despite its irrelevance to the case before it:

“We recognize, as did the Ferebee court, that ‘a cause-effect relationship need not be clearly established by animal or epidemiological studies before a doctor can testify that, in his opinion, such a relationship exists. As long as the basic methodology employed to reach such a conclusion is sound, such as use of tissue samples, standard tests, and patient examination, products liability law does not preclude recovery until a “statistically significant” number of people have been injured or until science has had the time and resources to complete sophisticated laboratory studies of the chemical. Id. at 1535-36.”

Wells, 788 F.2d at 745 (quoting Ferebee). Ferebee involved an injury that all parties agreed could be attributed to paraquat exposure without the need for epidemiologic studies; statistical analysis was not particularly germane.  In Wells, on the other hand, both sides relied upon studies that required statistical analyses for any sensible interpretation, and some of the studies actually reported statistically significant results.  The appellate court’s rhetoric was empty and irrelevant.

(to be continued)