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The Seventh Circuit Regresses on Rule 702

October 29th, 2013

Earlier this month, a panel of the Seventh Circuit of the United States Court of Appeal decided a relatively straight forward case by reversing the trial court’s exclusion of a forensic accountant’s damages calculation.  Manpower, Inc. v. Insurance Company of the State of Pennsylvania, No. 12‐2688 (7th Cir. Oct. 16, 2013).  In reversing, the appellate court disregarded a congressional statute, Supreme Court precedent, and Circuit decisional law.

The case involved a dispute over insurance coverage dispute and an economic assessment of Manpower, Inc.’s economic losses that followed a building collapse.  The trial court excluded Manpower’s accounting expert witness, Sullivan, who projected a growth rate (7.76%) for the plaintiff by comparing total revenues for a five month period in 2006 to the same five months in the previous year.  Id. at 8.  The historical performance, however, included a negative annual growth rate of 4.79% , over the years 2003 to 2009.  Over the five months immediately preceding Sullivan’s chosen period in 2006, the growth rate was merely 3.8%, less than half his projected growth rate.  Id.  Sullivan tried to justify his rather his extreme selectivity in data reliance by adverting to information that he obtained from the company about its having initiated new policies and installed new managers by the end of 2005.  Id.

The trial court held that Sullivan, who was not an expert on business management, had uncritically accepted the claimant’s proffered explanation for a very short-term swing in profitability and revenue.  Id. at 9.  While suggesting that Sullivan’s opinion was not “bulletproof,” the panel of the Seventh Circuit reversed.  The panel, which should have been reviewing the district court for potential “abuse of discretion,” appears to have made its own independent determination that Sullivan opinion was “sufficiently reliable to present to a jury.” Id. at 17.  In reversing, the panel explained that “the district court exercised its gatekeeping role under Daubert with too much vigor.” Id.

The panel attempted to justify its reversal by suggesting that a district court “usurps the role of the jury, and therefore abuses its discretion, if it unduly scrutinizes the quality of the expert’s data and conclusions rather than the reliability of the methodology the expert employed.” Id. at 18.  The panel’s reversal illustrates several methodological and legal confusions that make this case noteworthy beyond its mundane subject matter.

Of course, the most striking error in the panel’s approach is citing to a Supreme Court case, Daubert, which has been effectively superseded by a Congressional statute, Federal Rule of Evidence 702, in 2000:

“A witness who is qualified as an expert … may testify in the form of an opinion or otherwise if:

(a) the expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue;

(b) the testimony is based on sufficient facts or data;

(c) the testimony is the product of reliable principles and methods; and

(d) the expert has reliably applied the principles and methods to the facts of the case.”

Pub. L. 93–595, § 1, Jan. 2, 1975, 88 Stat. 1937; Apr. 17, 2000 (eff. Dec. 1, 2000); Apr. 26, 2011, eff. Dec. 1, 2011.)  Ironically, the Supreme Court’s Daubert case itself, had the Manpower panel paid attention to it, reversed the Ninth Circuit for applying a standard, the so-called Frye test, which predated the adoption of the Federal Rules of Evidence in 1975.  Rather than following the holding of the Daubert case, the panel got mired down in its dicta about a distinction between methodology and conclusion.  The Supreme Court itself abandoned his distinction a few years later in General Electric Co. v. Joiner, when it noted that

“conclusions and methodology are not entirely distinct from one another.”

522 U.S. 136, 146 (1997).

The panel of the Seventh Circuit concluded, without much real analysis, that the district court had excluded Sullivan’s opinions on a basis that implicated his conclusion and data selection, not his methodology.  Id. at 19-20.  The problem, of course, is that how one selects data of past performance to project future performance is part and parcel of the methodology of making the economic projection.  The supposed distinction advanced by the panel is illusory, and contrary to post-Daubert decisions, and the Congressional revision of the statute, which requires attention to whether “the testimony is based on sufficient facts or data; the testimony is the product of reliable principles and methods; and, the expert has reliably applied the principles and methods to the facts of the case.” Rule 702.

To make matters worse, the appellate court in Manpower proceeded to attempt to justify its reversal on grounds of “[t]he latitude we afford to statisticians employing regression analysis, a proven statistical methodology used in a wide variety of contexts.” Id. at 21. Here the appellate court suggests that if expert witnesses use a statistical test or analysis, such as regression analysis, it does not matter how badly they apply the test, or how worthless their included data are.  Id. at 22.  According to the Manpower panel:

“the Supreme Court and this Circuit have confirmed on a number of occasions that the selection of the variables to include in a regression analysis is normally a question that goes to the probative weight of the analysis rather than to its admissibility. See, e.g.,Bazemore v. Friday, 478 U.S. 385, 400 (1986) (reversing lower court’s exclusion of regression analysis based on its view that the analysis did not include proper selection of variables); Cullen v. Indiana Univ. Bd. of Trustees, 338 F.3d 693, 701‐02 & n.4 (7th Cir. 2003) (citing Bazemore in rejecting challenge to expert based on omission of variables in regression analysis); In re High Fructose Corn Syrup Antitrust Litigation, 295 F.3d 651, 660‐61 (7th Cir. 2002) (detailing arguments of counsel about omission of variables and other flaws in application of the parties’ respective regression analyses and declining to exclude analyses on that basis); Adams v. Ameritech Servs., Inc., 231 F.3d 414, 423 (7th Cir. 2000) (citing Bazemore in affirming use of statistical analysis based solely on correlations—in other words, on a statistical comparison that employed no regression analysis of any independent variables at all). These precedents teach that arguments about how the selection of data inputs affect the merits of the conclusions produced by an accepted methodology should normally be left to the jury.”

Id. at 22.

Again, the Seventh Circuit’s approach in Manpower is misguided. Bazemore involved a multivariate regression analysis in the context of a discrimination case.  Neither the Supreme Court nor the Fourth Circuit considered the regression at issue in Bazemore as evidence; rather the analysis was focused upon whether, within the framework of discrimination law, the plaintiffs’ regression satisfied their burden of establishing a prima facie case that shifted the burden to the defendant. No admissibility challenge was made to the regression in Bazemore under Rule 702.  Of course, the Bazemore litigation predates the Supreme Court’s decision in Daubert by several years.  Furthermore, even the Bazemore decision acknowledged that there may be

“some regressions so incomplete as to be inadmissible as irrelevant… .”

478 U.S. 385, 400 n.10 (1986).

The need for quantitative analysis of race and other suspect class discrimination under the equal protection clause no doubt led the Supreme Court, and subsequent lower courts to avoid looking too closely at regression analyses.  Some courts, such as the Manpower panel view Bazemore as excluding regression analysis from gatekeeping of statistical evidence, which magically survives Daubert. The better reasoned cases, however, even within the Seventh Circuit fully apply the principles of Rule 702 to statistical inference and analyses. See, e.g., ATA Airlines, Inc. v. Fed. Express Corp., 665 F.3d 882, 888–89 (2011) (Posner, J.) (reversing on grounds that plaintiff’s regression analysis should never have been admitted), cert. denied, 2012 WL 189940 (Oct. 7, 2012); Zenith Elecs. Corp. v. WH-TV Broad. Corp., 395 F.3d 416 (7th Cir.) (affirming exclusion of expert witness opinion whose extrapolations were mere “ipse dixit”), cert. denied, 125 S. Ct. 2978 (2005); Sheehan v. Daily Racing Form, Inc. 104 F.3d 940 (7th Cir. 1997) (Posner, J.) (discussing specification error).  See also Munoz v. Orr, 200 F.3d 291 (5th Cir. 2000).  For a more enlightened and educated view of regression and the scope and application of Rule 702, from another Seventh Circuit panel, Judge Posner’s decision in ATA Airlines, supra, is an essential starting place. See “Judge Posner’s Digression on Regression” (April 6, 2012).

There is yet one more flaw in the Manpower decision and its rejection of the relevancy of data quality for judicial gatekeeping.  Federal Rule of Evidence 703 specifically addresses the bases of an expert witness’s opinion testimony.  The Rule, in relevant part, provides that:

“If experts in the particular field would reasonably rely on those kinds of facts or data in forming an opinion on the subject, they need not be admissible for the opinion to be admitted.”

Here the district court had acted prudently in excluding an expert witness who accepted the assertions of new management that it had, within a very short time span, turned a company from a money loser into a money earner.  As any observer of the market knows, there are too many short-term “fixes,” such as cutting personnel, selling depreciated property, and the like, to accredit any such short-term data as “reasonably relied upon.”  See In re Agent Orange Product Liability Lit., 611 F. Supp. 1223, 1246 (E.D.N.Y. 1985) (excluding opinions under Rule 703 of proffered expert witnesses who relied upon checklists of symptoms prepared by the litigants; “no reputable physician relies on hearsay checklists by litigants to reach a conclusion with respect to the cause of their affliction”), aff’d on other grounds, 818 F.2d 187 (2d Cir. 1987), cert. denied, 487 U.S. 1234 (1988).

Manpower represents yet another example of Court of Appeals abrogating gatekeeping by reversing a district judge who attempted to apply the Rules and the relevant Supreme Court precedent.  The panel in Manpower ignored Congressional statutory enactments and precedents of its own Circuit, and it relied upon cases superseded and overruled by later Supreme Court cases.  That’s regression for you.

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Bendectin, Diclegis & The Philosophy of Science

October 26th, 2013

In April of this year, the United States Food and Drug Administration (FDA) approved Diclegis, a combination of doxylamine succinate and pyridoxine hydrochloride for sale in the United States, for pregnant women experiencing nausea and vomiting. See FDA News Release, “FDA approves Diclegis for pregnant women experiencing nausea and vomiting,” (April 8, 2013). The return of this drug to the United States market was held up as a triumph of science over the will of the lawsuit industry. See Gideon Koren, “The Return to the USA of the Doxylamine-Pyridoxine Delayed Release Combination (Diclegis®) for Morning Sickness — A New Morning for American Women,” 20 J. Popul. Ther. Clin. Pharmacol. e161 (2013).

The sponsor of the drug, Duchesnay USA, wisely did not use the medication’s former name, Bendectin, which was the victim of a litigation industry jihad in the late 1970s through the mid-1990s. The plaintiffs’ lawyers’ war against Bendectin and its United States manufacturer is chronicled in two book-length accounts, and hundreds of articles. See Joseph Sanders, Bendectin on Trial: A Study of Mass Tort Litigation (Ann Arbor 1998); Michael D. Green, Bendectin and Birth Defects: The Challenges of Mass Toxic Substances Litigation (Philadelphia 1996).

As recently approved by the FDA, Declegis is categorized as “Pregnancy Category A,” which means that it is medication indicated for use in pregnant women. Most drugs are not tested in pregnant women in randomized clinical trials for obvious ethical and practical reasons. Perhaps one of the good things that came out of the Bendectin litigation wars was that Bendectin became one of the most intensely studied medications available for pregnant women. Another good thing was the achievement of evidence-based standards for expert witness opinion testimony in federal court. See David Bernstein, “Bendectin is Back” (April 9, 2013).

According to FDA regulations, Category A is defined:

“(1) Pregnancy category A. If adequate and well-controlled studies in pregnant women have failed to demonstrate a risk to the fetus in the first trimester of pregnancy (and there is no evidence of a risk in later trimesters), the labeling must state: ‘Pregnancy Category A. Studies in pregnant women have not shown that (name of drug) increases the risk of fetal abnormalities if administered during the first (second, third, or all) trimester(s) of pregnancy. If this drug is used during pregnancy, the possibility of fetal harm appears remote. Because studies cannot rule out the possibility of harm, however, (name of drug) should be used during pregnancy only if clearly needed.’ The labeling must also contain a description of the human studies. If animal reproduction studies are also available and they fail to demonstrate a risk to the fetus, the labeling must also state: ‘Reproduction studies have been performed in (kinds of animal(s)) at doses up to (x) times the human dose and have revealed no evidence of impaired fertility or harm to the fetus due to (name of drug).’ The labeling must also contain a description of available data on the effect of the drug on the later growth, development, and functional maturation of the child.

21 CFR § 201.57 (c)(9)(i)(A)(1) (April 2012).

A Litmus Test for Philosophy of Science?

The inability to discriminate between valid and invalid science should be a disqualifying characteristic in a putative philosopher of science, or a putative expert, for that matter. Professor Susan Haack, whose writings provide both insight and confusion on the role of science in the law, revealed her robust biases and prejudices in commenting upon the Bendectin litigation. These revelations should raise red flags about her objectivity in commenting on the legal process. See Susan Haack, “Irreconcilable Differences? The Troubled Marriage of Science and Law,” 72 Law & Contemporary Problems 1 (2009).

Haack’s paper on the marital discord was based upon her presentation at the Fourth Coronado Conference, organized by SKAPP (The Project on Scientific Knowledge and Public Policy), an ideological group dedicated to opening the courthouse doors to every quackacademic theory, and shadily funded by the litigation industry of plaintiffs’ lawyers from their left-over spoils from the silicone breast implant litigation. See SKAPP A LOT (April 30, 2010); “Haacking at the Truth – Part Two” (Oct. 31, 2010).

Haack provided examples of “marginal” science and witnesses who disturb her for biases and prejudices she perceives in these witnesses. Haack focuses upon Dr. Robert Brent, a toxicologist, who appears to her as Merrell Dow’s expert witness “always ready to testify that Bendectin does not cause birth defects.” Id. At 17. Haack presented no evidence or basis to suggest that Brent was wrong, and indeed, Brent published widely on his views of the subject. Multiple publications do not necessarily mean that Brent was right, but at least he was willing to subject himself to professional peer review, and post-publication, professional challenges. Still, Haack is distressed that Dr Robert Brent opines with “unwarranted certainty” that Bendectin does not cause birth defects, but she offers no suggestion or support that his certainty was or is misplaced.

In stark contrast, Haack expressed no discomfort with Bendectin plaintiffs’ expert witness, Dr Done, or with the facile ease with which he opined with scientific certainty that Bendectin causes birth defects. Here there really is a great deal of empirical evidence, and along with the FDA’s recent approval of Diclegis for use in pregnant women, the evidence has vindicated Dr. Brent’s views on the safety and efficacy of Bendectin/Diclegis. Dr. Done’s subjective appreciation of “flaws” in some clinical studies does not turn criticism into affirmative evidence in favor of the opinion that he so zealously, and overzealously, advocated in many Bendectin cases, for his own substantial pecuniary benefit. What is remarkable about Haack’s article is that she singles out Dr. Brent in the context of a discussion of “marginal” and “willing” testifying scientists, but she omits any mention of the plaintiffs’ cadre of ready, willing, and somewhat disreputable testifiers. Perhaps even more remarkable is that Haack overlooks that Dr. Done was essentially fired from his university for his entrepreneurial testimonial activities of dubious scientific worth, and that he probably lied about his credentials. See Michael Green, Bendectin and Birth Defects: The Challenges of Mass Toxic Substances Litigation 280 – 82 (Philadelphia 1996) (citing decisional law in which Done’s lack of veracity was judicially noted).

Of course, what is most remarkable about Haack’s infatuation with Dr. Alan Done and his mosaic theory is that the theory was the concoction of plaintiffs’ lawyer, Barry Nace, and that the theory leads to such a palpably incorrect result. Barry Nace was one of the lead plaintiffs’ counsel in the Bendectin litigation. Nace was also formerly President of the litigation industry’s principal lobbying organization, the American Trial Lawyers Association (now the AAJ). After the second Ninth Circuit Daubert decision, Nace declined to pursue one of his Bendectin cases, and his client sued him. Nace’s attorney moved for summary judgment in August 1998, on grounds that included the assertion that “courts soundly and uniformly reject the notion that Bendectin causes birth defects.” See David Bernstein, “A Day Late and a Dollar Short on Bendectin” (June 28, 2005).

This is the same Barry Nace lauded by Michael Green for having devised the notorious matrix theory of scientific evidence (a.k.a. the tsumish theory). Michael D. Green, “Pessimism About Milward,” 3 Wake Forest J. Law & Policy41, 62-63 (2013). Professor Haack sees Nace’s matix theory as the practical application of some of her theories. Susan Haack, “Irreconcilable Differences? The Troubled Marriage of Science and Law,” 72 Law & Contemporary Problems 1, 17 (2009); Susan Haack, “Proving Causation: The Holism of Warrant and the Atomism of Daubertm” 4 J. Health & Biomedical Law 273, 274-78 (2008). Haack’s embrace of the dubious Bendectin causal claims as supported by her matrix theory of causal inference raises the issue why we should credit a theory in the face of such a compelling counter example? As Professor Ronald Allen put the matter, before Bendectin was reintroduced into the United States market this year:

“Given the weight of evidence in favor of Bendectin’s safety, it seems peculiar to argue for mosaic evidence from a case in which it would have plainly been misleading.”

Ronald J. Allen and Esfand Nafisi, “Daubert and its Discontents,” 76 Brooklyn L. Rev. 132, 148 (2010). Peculiar indeed. Professor Allen’s point is important for its wide-ranging implications. Methodologies that yield false-positive results are unreliable. Perhaps a methodology can be saved if we could quantify that a given methodology rarely yields such false results, but the matrix theory of Barry Nace and his expert witnesses seems so vague and insubstantial that no one, in all likelihood, could frame a test for the generalized approach. Expert witnesses perhaps should be judged by their track record over time, as well. See David Kaye, “The Experts in Daubert.”[1]

 

[1] Dr. Alan Done (pediatrician, pharmacology, toxicology); Dr. Jay Glasser (biostatistician, epidemiologist); Dr. Adrian Gross (veterinarian); Dr. Stuart Newman (developmental biologist); Dr. Wayne Snodgrass (Assoc. Professor of Pediatrics, Pharmacology, and Toxicology); Dr. Shanna Swan (epidemiologist); Dr. Johannes Thiersch (pathologist and pharmacologist); Dr. John Palmer (Professor of pharmacology).

 

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Christopher Bryson and the Problem of Political Science

October 12th, 2013

Fluoridation of water has long been a “political science” issue, with radical libertarians and anarchists viewing fluoridation as the high-water mark of state paternalism.  The motive to misstate and misrepresent the science may at times be obvious, but individual statements, standing alone, may be difficult to judge.

Fluorine chemistry and toxicology are sufficiently advanced that misrepresentations should be easy to detect.  Fluorine is a halogen; the lightest in the series.  As a gas, fluorine is extremely reactive and toxic, as are other halogen gases, such as chlorine.  Fluorine gas was used for uranium enrichment in the Manhattan project, and project scientists conducted research on fluorine toxicity to help them set exposure limits in a new manufacturing process.

As devotees of Breaking Bad no doubt have learned, hydrogen fluoride is extremely toxic and corrosive.  Other halogen-based acids are, of course, toxic and corrosive, such as hydrogen chloride.

Compounds of fluorine are generically fluorides, and the properties of the salts and compounds varies considerably with the cation and the chemical structures involved.  Many modern medications, such as atorvastatin and fluoxetine contain fluorine in their chemical structures.  The toxicology of the fluorine compounds must, therefore, take into account the variability of structure and function of fluorine.  Toxicity of fluorine gas or of hydrogen fluoride cannot be “extrapolated” to a simple sodium salt, and more than the toxicity of chlorine gas can be imply the toxicity or ordinary table salt, sodium chloride.  The allergenicity of a compound such as potassium aluminumtetrafluoride cannot be the basis for asserting the immunogenicity of a simple alkali salt.

Recently, I came across a YouTube video of a journalist, Christopher Bryson, holding forth on his perception of a vast conspiracy to poison people by the fluoridation of drinking water.  Bryson’s passion and selectivity in making his case resembles the deep flaws of our tort system, which allows lawyers and expert witnesses to overwhelm judges and juries with emotion, selectivity, and overstatement.  Bryson refers to all fluorine chemicals, whether the elemental gas, the acid, or the many complex and variable salts as “fluoride.”  Occupational and environmental exposures to hydrogen fluoride are equated with micromolar levels of sodium fluoride in drinking water. Never once does he actually quantitate the exposures he labels as “toxic.” Largely, Bryson proceeds by ad hominems, ad nauseam.  If scientists have industry connections, they are bad, and their science is corrupt.  If a scientist has ever done something productive (e.g., George L. Waldbott), and he opines that water fluoridation is bad, then that scientist must be correct.  Apparently, Bryson has never heard of Linus Pauling and his Vitamin C fiasco.  See K. Frank Austen, M. Dworetzky, Richard S. Farr, G.B. Logan, S. Malkiel, E. Middleton Jr., M.M. Miller, Roy Patterson, C.E. Reed, S.C. Siegel, and P.P. Van Arsdel Jr., “A statement on the question of allergy to fluoride as used in the fluoridation of community water supplies,” 47 J. Allergy & Clinical Immunology 347 (1971) (“no”).

Bryson makes for an interesting case study in hysteria.  He is also very much a public example of the tone and substance of many of the plaintiffs’ theories that clog the civil dockets of our court system.  Bryson’s passion and intensity — heat without illumination  — are reminiscent of the courtroom antics in many a so-called “toxic tort” case.  Bryson’s video is thus a good place to start to try to understand science in the courtroom, and the need for strong gatekeeping.  The potential for inflammatory advocacy, distortion, and misrepresentation have always been part of legal proceedings, but when it comes to advocacy about claims that turn on “scientific” evidence, there is a difference.  Juries in common law cases, in 1789, were not confronted with the abuses of the sort that Bryson so well exemplifies.

The Bryson video led me to look at Bryson’s book, The Fluoride Deception.  The book starts with “Notes on Terminology,” which warns that

“THE TERMS fluorine and fluoride should not be confused in a book about chemical toxicity.”

* * *

“In these pages I’ve tried to be clear when I’m referring to the element fluorine or to a compound, a fluoride. And because different fluoride compounds often have unique toxicities, where relevant or possible, I have also given the compound’s specific name.”

So far so good, but then Bryson, having baited, switches:

“Mostly, however, for simplicity’s sake, I have followed convention and used the shorthand fluoride when referring to the element and its multiple manifestations, a procedure approved and used by the U.S. National Academy of Sciences.”

Christopher Bryson, The Fluoride Deception at xi (2004).

Fluoride deception indeed Mr. Bryson.  The cited source for the indiscriminate use of fluoride makes clear that it uses “fluoride” as a general term when differentiation is not necessary for its discussion.  It is not, however, a basis for conflating or confusing the toxicities of fluorine species or doses.  National Research Council, Biological Effects of Atmospheric Pollutants: Fluorides 3 (1971).  Bryson provides an apt example of how science communication works in politicized contexts, such as the courtroom or the legislature.

Posted in Causation, Rule 702, Scientific Evidence | Comments Off on Christopher Bryson and the Problem of Political Science

LNT in Milward v. Acuity Specialty Products Group

September 28th, 2013

Professor Edward J. Calabrese previously has written about the shadowy origins of the linear no threshold (LNT) model of cancer causation.  See The Dubious Origins of the Linear No Threshold Model of Carcinogenesis (Jan. 10, 2013).  Recently, Calabrese has deepened his historical scholarship with two additional, interesting articles. See “Toxicologist Says NAS Panel ‘Misled the World’ When Adopting Radiation Exposure Guidelines” (Aug. 13, 2013).

These articles, now available online, are important tools in the work chest of lawyers who litigate health effect claims.  Edward J. Calabrese, “How the US National Academy of Sciences misled the world community on cancer risk assessment: new findings challenge historical foundations of the linear dose response,” 87 Arch. Toxicol. (2013) (in press); Edward J. Calabrese, “Origin of the linearity no threshold (LNT) dose–response concept,” 87 Arch. Toxicol. 1621 (2013). Professor Calabrese illuminates the exaggerations and ipse dixit in the origins of the linear-no threshold model, first applied to radiogenic cancers, and later to human carcinogenesis more generally.

On remand from the First Circuit, the trial judge in Milward, now the Hon. Douglas Woodlock, faced a renewed Rule 702 motion directed to Milward’s specific causation expert witnesses.  Milward v. Acuity Specialty Products Group, Inc., Civil Action No. 07–11944–DPW, 2013 WL 4812425 (D. Mass. Sept. 6, 2013). Plaintiffs attempted to invoke the dubious LNT concept to argue that benzene should be in the “differential” for ascertaining the specific cause of Mr. Milward’s APL. In performing a careful Rule 702 analysis, Judge Woodlock rule that, “[t]o the extent Butler [Milward’s expert witness] seeks to establish specific causation based on the argument that any level of benzene is sufficient to cause leukemia—a so-called “no safe level,” “no threshold,” or “linear” model—her opinion is inadmissibly unreliable.”  Id. at *8.

In recognizing Dr. Butler’s reliance upon LNT concepts in civil litigation as unreliable, Judge Woodlock followed the lead of other courts, within the First Circuit, which have previously rejected expert witness opinion testimony founded upon the LNT model.  See, e.g., Whiting v. Boston Edison Co., 891 F.Supp. 12, 25 (D.Mass.1995) (“[t]he linear non-threshold model cannot be falsified, nor can it be validated. To the extent that it has been subjected to peer review and publication, it has been rejected by the overwhelming majority of the  scientific community. It has no known or potential rate of error. It is merely an hypothesis.” ); Sutera v. Perrier Group of America Inc., 986 F.Supp. 655, 666 (D.Mass.1997) (“Accordingly, although there is evidence that one camp of scientists … believes that a non-linear model is appropriate basis for predicting the risks of low-level exposures to benzene, there is no scientific evidence that the linear no-safe threshold analysis is an acceptable scientific technique used by experts in determining causation in an individual instance.”).  Strong precedent outside the First Circuit also supports Judge Woodlock’s holding.  See Allen v. Pennsylvania Eng’g Corp., 102 F.3d 194, 198 (5th Cir.1996); Henricksen v. ConocoPhillips Co., 605 F.Supp. 2d 1142, 1166 (E.D.Wash.2009) (“[Plaintiffs’ expert witness’s] theory that any amount of exposure more than negligible should be considered substantial risk factor for AML flies in the face of the scientific literature reviewed and other expert testimony in this case that there is a threshold or dose below which you do not see a statistically significant risk of developing AML.”); In re W.R. Grace & Co. 355 B.R. 462, 476 (Bankr. D. Del. 2006) (the “no threshold model . . . flies in the face of the toxicological law of dose-response . . . doesn’t satisfy Daubert, and doesn’t stand up to scientific scrutiny”); Cano v. Everest Minerals Corp., 362 F. Supp. 2d 814, 853–54 (W.D. Tex. 2005) (even accepting the linear, no-threshold model for uranium mining and cancer, it is not enough to show exposure, you must show causation as well). See also McClain v. Metabolife Int’l, Inc., 401 F.3d 1233, 1244 (11th Cir. 2005) (“in evaluating the reliability of the experts’ opinions on general causation, it would help to know how much additional risk for heart attack or ischemic stroke Metabolife consumers have over the risks the general population faces”). National Bank of Commerce v. Assoc. Milk Producers, 22 F. Supp. 2d 942, 960 (E.D. Ark. 1998), aff’d, 191 F.3d 858 (8th Cir.1999). See generally Federal Judicial Center, Reference Manual on Scientific Evidence, at 643 n. 28 (3d ed.2011).

The district court in Milward held that because Dr. Butler “did not and could not quantify a threshold exposure level for benzene, Milward cannot posit that his cumulative exposure level crossed a relevant threshold.” Milward, 2013 WL 4812425, at 8.  In addressing Milward’s reliance upon LNT, Judge Woodlock rejected three specious arguments, which frequently recur in Rule 702 litigation.

First, the district saw through the argument that the claimed benzene-APL LNT model was good science because the United States Environmental Protection Agency (EPA) relies upon it.  The EPA applies the LNT model for benzene

“due to uncertainty about the shape of the dose-response curve below 40 ppm-years.”

Id. at 8[1]. The district court recognized that the EPA’s reasoning was a “classic example of a cautious prophylactic administrative rule” that “does not support the reliability of the linear, no-threshold model in establishing specific causation.”  Id.  In so ruling, the Milward district court joins a long line of courts that have distinguished administrative rulemaking from civil litigation standards for causation.  See, e.g., Allen v. Pa. Eng’g Corp., 102 F.3d 194, 198 (5th Cir. 1996)(“This methodology results from the preventive perspective that the agencies adopt in order to reduce public exposure to harmful substances. The agencies’ threshold of proof is reasonably lower than that appropriate in tort law, which traditionally makes more particularized inquiries into cause and effect.”)

Second, the Milward district court also saw through plaintiffs’ argument that the First Circuit’s embrace of its “weight of the evidence” general causation approach, which appears to enjoy support among federal bureaucrats, required approval of plaintiffs’ attempt to use a LNT prophylactic or precautionary approach. Milward, 649 F.3d at 18 & n. 9.  Plaintiffs have the burden of showing reliability of the LNT model, and the EPA’s acknowledged uncertainty about the model for benzene was an insuperable barrier to their success.  Milward, 2013 WL 4812425, at 8 & n.4.

Third, the district court rejected Dr. Butler’s attempt to “bait and switch,” by pointing to a study on hematotoxicity as opposed to carcinogenicity.  Butler argued that there was “no clear evidence of a threshold below which benzene does not cause hematotoxicity in humans.”[2] The court recognized that the study referred to the lack of a hematotoxicity threshold for low average doses of benzene. Hematotoxicity is not necessarily induction of APL; nor was the lack of clear evidence for a threshold evidence against a threshold.

Even in the regulatory realm, the LNT model is losing traction.  See Chlorine Chemistry Council v. EPA, 206 F.3d 1286, 1287 (D.C. Cir. 2000) (invalidating EPA regulation under the Safe Drinking Water Act, when the EPA persisted in using an LNT model, after it had concluded that chloroform, a contaminant in drinking water from chlorination exerted a “a nonlinear mode of carcinogenic action”).  In the scientific realm, researchers can merely watch in amazement at the “political science” that proceeds under a mistaken, outdated model of carcinogenesis.  See, e.g., Brant A. Ulsh, “Checking the Foundation: Recent Radiobiology and the Linear No-Threshold Theory,” 99 Health Physics 747 (2010) (“However, a large and rapidly growing body of radiobiological evidence indicates that cell and tissue level responses to this damage, particularly at low doses and/or dose-rates, are nonlinear and may exhibit thresholds. To the extent that responses observed at lower levels of biological organization in vitro are predictive of carcinogenesis observed in vivo, this evidence directly contradicts the assumptions upon which the microdosimetric argument is based.”); Bernard L. Cohen, “The Linear No-Threshold Theory of Radiation Carcinogenesis Should Be Rejected,” 13 J. Am. Physicians & Surgeons 70, 75 (2008) (“The conclusion from the evidence reviewed in this paper and more extensively elsewhere is that the linear-no threshold theory (LNT) fails very badly in the low-dose region, grossly overestimating the risk from low-level radiation. This means that the cancer risk from the vast majority of normally encountered radiation exposures is much lower than given by usual estimates, and may well be zero or even negative.”); Maurice Tubiana, Ludwig E. Feinendegen, Chichuan Yang, and Joseph M. Kaminski, “The Linear No-Threshold Relationship Is Inconsistent with Radiation Biologic and Experimental Data,” 251 Radiology 13, 13, 15-16, 18 (2009) (noting that LNT model is obsolete in view of known upregulation of cellular protective mechanisms against cancer; “LNT was a useful model half a century ago. But current radiation protection concepts should be based on facts and on concepts consistent with current scientific results and not on opinions. Preconceived concepts impede progress; in the case of the LNT model, they have resulted in substantial medical, economic, and other societal harm.”).


[1] The court EPA Office of Research and Development, Carcinogenic Effects of Benzene: An Update, at 38–39 (April 1998).

[2] Dr. Butler cited Richard B. Hayes, et al., “Benzene and Lymphohemaptopoietic Malignancies in Humans,” 40 Am. J. Indus. Med. 117, 120 (2001).

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Differential Diagnosis in Milward v. Acuity Specialty Products Group

September 26th, 2013

Graffiti on the bathroom wall in the building that housed my undergraduate college’s philosophy department:

How does a philosopher treat constipation?

By using iterative disjunctive syllogism.

The joke is that this variety of syllogism is nothing other than reasoning by the process of elimination.

A or B or C

~A

B or C

~B

∴C

The syllogism works as a valid form of argument if the premises are all true.  So, if we start with three possible causes, A, B, and C, and we know that one or more of them caused an outcome, then we might proceed by the process of elimination to show that we can rule out all the others but the alleged cause.  The first line of the syllogism is true if at least one of the disjuncts is true.  As we rule out particular disjuncts upon learning that they are in fact false, we are left we a smaller set of disjuncts.  If we can proceed until we are left with the disjunct of interest, we may actually have succeeded in identifying a cause in fact of the particular case.

In the syllogistic argument above, we must be able to show that A and B are false before we can then conclude that C is true.

In differential etiology, we start with known causes, exposures or conditions that are known to be capable of causing a disease or disorder.  We do not know whether the potential causes were actually in play in a given case.  If we can use this syllogistic reasoning to conclude that the defendant’s product was a cause of the of the plaintiff’s harm, we might actually have shown specific causation in a reliable fashion.  If, however, we cannot proceed to a conclusion that unequivocally includes the defendant’s product, we are left with an indeterminate outcome, and the plaintiff must take nothing.

The Milward case was recently back in the news.  On remand from the First Circuit, the district judge, now the Hon. Douglas Woodlock, faced a renewed Rule 702 motion directed to Milward’s specific causation expert witnesses.  Milward v. Acuity Specialty Products Group, Inc., Civil Action No. 07–11944–DPW, 2013 WL 4812425 (D. Mass. Sept. 6, 2013).

Judge Woodlock wryly commented upon the First Circuit’s ignoring the statutory mandate of Rule 702, by its embracing caselaw that predated the 2000 statutory amendment of the Rule:

“While a 2000 amendment to Fed.R.Evid. 702 codified a rigorous reliability test, the Daubert line of cases has been read by the First Circuit as “demand[ing] only that the proponent of the evidence show that the expert’s conclusion has been arrived at in a scientifically sound and methodologically reliable fashion.” Ruiz–Troche v. Pepsi Cola of Puerto Rico Bottling Co., 161 F.3d 77, 85 (1st Cir.1998). “So long as an expert’s scientific testimony rests upon good grounds based on what is known, it should be tested by the adversarial process, rather than excluded for fear that jurors will not be able to handle the scientific complexities.” Milward, 639 F.3d at 15 (internal quotation and citation omitted).”

Milward, at *3.  After noting the statute’s “rigorous reliability test,” and the First Circuit’s having  diluted the statutory standard by drawing from pre-statute caselaw, Judge Woodlock got down to the business of gatekeeping, by examining the facts of record before him.

The defense’s first challenge was to Milward’s industrial hygienist’s opinion that quantified his benzene exposure.  The industrial hygienist, James Stewart, estimated Milward’s benzene exposure, both total and from individual products.  The defense challenge was interesting, given that plaintiffs have challenged defendants’ use of similar exposure recreations to advance apportionments that will defeat joint and several liability.  The district court denied the defense challenge, and turned its attention to the specific causation issue, which proved to be a good example of patho-epistemology .

The plaintiffs relied upon Dr. Sheila Butler, who was board certified in occupational medicine, pathology, and hematology, to opine that Brian Milward’s exposure was responsible for causing his Acute Promyelocytic Leukemia (“APL”), a rare subtype of Acute Myeloid Leukemia (“AML”). Butler’s opinion was simple if not simpistic:

“there is a ‘reasonable medical probability that there is a direct causal association between Mr. Milward’s APL and his excessive occupational exposure to benzene containing substances’ based primarily on

(1) the fact that his exposure to benzene preceded his development of APL, and

(2) a survey of studies showing increased AML risk following low average dose exposures to benzene.”

Milward at *6.

Simplistic and simply wrong. Butler had equated exposure and some risk, unquantified, with specific causation, an empty and unsupported assertion.  Judge Woodlock did not dignify this subjective opinion with further discussion, but turned his attention to Butler’s “differential diagnosis” analysis by which Butler claimed to have eliminated other potential causes of Milward’s APL such that she could say that benzene was a specific cause.

The district court started from the premise that so-called differential diagnosis is useful and accepted for assessing causation. Id. at *7 (citing Baker v. Dalkon Shield Claimants Trust, 156 F.3d 248, 253 (1st Cir.1998).  For some reason, however, the court emphasized that the differential etiology was particularly appropriate when the expert witness’s opinion lacks a foundation of epidemiologic studies or a “well-established threshold exposure levels at which disease occurs.”  The district court did not explain what it possibly could have meant by this emphasis, and I doubt that there is any basis for the court’s statement.

The real issue in Milward, on remand, was whether Dr. Butler applied the differential etiology in a reliable manner.  The defense argued that Dr. Butler failed to rule out competing risk factors, Milward’s prior smoking, and his morbid obesity, as causes of Milward’s APL.  The court dismissed this challenge with the recognition that plaintiffs might still prevail if Milward’s disease resulted from either benzene and smoking or benzene, smoking, and obesity. Sadly, the court did not address the quality or quantity of the evidence for smoking, or for obesity, and APL; nor did it address the magnitude of the associations that were being claimed by the defense, or by the plaintiffs.  The court did not explore the evidentiary base for the defense assertion that smoking or obesity causes APL such that it should be in the first line of the iterative disjunctive syllogism.

The problem, of course, was not the plaintiffs’ failure to rule out obesity or smoking, but their failure to rule out the unknown factors, which account for the solid majority of APL cases.  Indeed, in the first round of Rule 702 briefings and hearings, plaintiffs’ expert witness, Dr. Martin Smith, opined that between 70 and 80 percent of APL cases are idiopathic; that is, they have no known cause.  Id. at *7.  The syllogism thus becomes very difficult because one proposition in the first line of the argument is that the cause is unknown, and the plaintiff cannot arrive at the conclusion that his APL was caused by benzene unless and until he provides reliable evidence that more likely than not, his APL disease was not caused by one or more of the unknown causes.  In other words, plaintiffs must show that the APL was not a background case that would have occurred regardless of occupational benzene exposure, and perhaps regardless of occupational exposure with obesity and smoking.  Judge Woodlock, relying heavily upon the Restatement (Third) of Torts expressed the matter this way:

“When a disease has a discrete set of causes, eliminating some number of them significantly raises the probability that the remaining option or options were the cause-in-fact of the disease.  Restatement (Third) of Torts: Phys. & Emot. Harm § 28, cmt. c(4) (2010) (‘The underlying premise [of differential etiology] is that each of the[] known causes is independently responsible for some proportion of the disease in a given population.  Eliminating one or more of these as a possible cause for a specific plaintiff’s disease increases the probability that the agent in question was responsible for that plaintiff’s disease.’). The same cannot be said when eliminating a few possible causes leaves not only fewer possible causes but also a high probability that a cause cannot be identified. Id. (‘When the causes of a disease are largely unknown … differential etiology is of little assistance’.).”

In the face of this irrefutable logic of this part of comment c, Butler argued that she had “ruled out” idiopathic APL by “ruling in” benzene.  Of course, benzene had to be postulated as a general cause in order for it to be placed into the first line of the syllogism, but Butler’s assertion about ruling in benzene as a specific cause is truly an ipse dixit, a non sequitur, and a petitio principii, all rolled into one opinion.  After all, the APL case may have arisen out of benzene exposure and the unknown causes, or only the unknown (idiopathic) causes.  Butler cannot rule in benzene until she rules out idiopathic causes as the sole specific causes in this case. To be fair, the prevalence of idiopathic cases cited by Martyn Smith might be lower in a population with heavy benzene exposure, assuming Smith’s general causation were true, but again, such an acknowledgment would only raise the question of what the prevalence of idiopathic cases is in a population of exposure that looked like Mr. Milward’s.

Dr. Butler argued that Martyn Smith had previously ruled in benzene, but that was only as a general cause that can then be represented as one disjunct in the first line of the syllogism.  Here Judge Woodlock identified another gap between Smith’s general causation opinion and Dr. Butler’s attempt to use Smith’s opinion to place benzene into the differential etiology for Mr. Milward.  On this remand, the plaintiffs had to show that “the levels of exposure that are hazardous to human beings generally as well as the plaintiff’s actual level of exposure.” Id. (citing Westberry v. Gislaved Gummi AB, 178 F.3d 257, 263-64 (4th Cir.1999) (talcum powder undisputedly could cause sinus problems, and plaintiff was exposed at levels known to be causative).  The court suggested that Milward had not yet shown that exposure at the levels he experienced could cause APL.  Of course, even if Milward sustained cumulative exposures capable of causing APL, this fact sufficed only to place benzene into the differential diagnosis, and it did not advance the iterative disjunctive syllogism to a conclusion of either a single or multiple disjuncts that included benzene.

Judge Woodlock did a good job of saving the First Circuit from the notoriety of its general causation decision in the Milward case. The new trial court decision is a strong reminder that risk does not equal causation.  Differential etiology cannot rule out idiopathic cause(s) as the sole specific cause of a plaintiff’s disease unless there is a fingerprint of causation that makes the risk identifiable as a cause in a specific case.  Such a fingerprint or biomarker was apparently absent in the Milward case.  Similarly, the differential etiology might rule out putative specific causes on a probabilistic basis if the idiopathic cases made up a small number of all the cases in relation to the number of cases that arise from the exposure that is the subject of the litigation.

The Milward decision joins other soundly decided differential diagnosis cases coming out of the First Circuit.  See, e.g., Plourde v. Gladstone, 190 F. Supp. 2d 708, 722-723 (D. Vt. 2002) (excluding testimony where expert failed to rule out causes of plaintiff’s illness other than exposure to herbicides); Whiting v. Boston Edison Co., 891 F. Supp. 12, 21 n.41 (D. Mass. 1995) (noting that differential diagnosis cannot be used to support conclusion of specific causation when 90% disease cases are idiopathic).

But lest anyone get too comfortable with the notion that this issue has been mastered by the federal judiciary, keep in mind that there are some really poorly reasoned cases out there. See, e.g., Allen v. Martin Surfacing, 263 F.R.D. 47, 56 (D. Mass. 2008) (admitting general and specific causation testimony to be tested by adversary process, rather than excluded altogether, despite paucity of epidemiologic evidence and general acceptance that there are no known causes of amyotrophic lateral sclerosis).

The limits of the “process of elimination” approach has been addressed by some scientific organizations, such as the Teratology Society, in the particularly demanding context of determining a cause for a child’s congenital malformation:

“Biologic plausibility includes a consideration of alternative explanations for the outcome in an individual plaintiff. For example, if a plaintiff has a birth defect syndrome caused by a known genetic disorder, chemical exposure becomes implausible as a cause of the abnormality in that particular individual. The consideration of alternative explanations is sometimes misused by expert witnesses to mean that failure to find an alternative explanation for an outcome is proof that the exposure at issue must have caused the outcome. A conclusion that an exposure caused an outcome is, however, based on positive evidence rather than on lack of an alternative explanation.”

The Public Affairs Committee of the Teratology Society, “Teratology Society Public Affairs Committee Position Paper Causation in Teratology-Related Litigation,” 73 Birth Defects Research (Part A) 421, 423 (2005).

A brief, partial survey of differential etiology cases is set out below.

SECOND CIRCUIT

McCullock v. H.B. Fuller Co., 61 F.3d 1038, 1044 (2d Cir. 1995) (defining differential etiology as an analysis “which requires listing possible causes, then eliminating all causes but one”)

Prohaska v. Sofamor, S.N.C., 138 F. Supp. 2d 422, 439 (W.D.N.Y. 2001) (excluding expert’s opinion and granting summary judgment where expert “was unable to rule out, to a reasonable degree of medical certainty, [plaintiff’s] pre-existing condition, scoliosis, as a current cause of her pain”)

Zwillinger v. Garfield Slope Hous. Corp., 1998 WL 623589, at *20 (E.D.N.Y. Aug. 17, 1998) (excluding testimony and granting summary judgment where expert failed to rule out alternative causes of plaintiff’s immunotoxicity syndrome)

THIRD CIRCUIT

Magistrini v. One Hour Martinizing Dry Cleaning, 180 F. Supp. 2d 584, 608-610 (D.N.J. 2002) (excluding testimony of expert who sought to testify that dry cleaning fluid caused leukemia, but failed to rule out smoking as an alternative cause), aff’d, 68 F. App’x 356 (3d Cir. 2003)

In re Paoli R.R. Yard PCB Litig., 2000 WL 274262, at *5 (E.D. Pa. March 1, 2000) (expert’s opinion should be excluded “because she failed to rule out alternative causes” of plaintiff’s injuries)

Kent v. Howell Elec. Motors, 1999 WL 517106, at * 5 (E.D. Pa. July 20, 1999) (excluding expert testimony and granting summary judgment because expert could “not rule out reasonable alternative theories of what caused the retaining ring to fail”);

O’Brien v. Sofamor, 1999 WL 239414, at *5 (E.D. Pa. Mar. 30, 1999) (excluding expert’s testimony and granting summary judgment where plaintiff “offer[ed] no evidence that [plaintiff’s experts] performed a differential diagnosis, or even considered other potential causes” of plaintiff’s back condition)

Schmerling v. Danek Med., Inc., 1999 WL 712591, at *9 (E.D. Pa. Sept. 10, 1999) (excluding expert’s testimony and granting summary judgment on the grounds that expert’s failure to rule out alternative causes “alone warrants a determination that the expert’s methodology is unreliable”);

Turbe v. Lynch Trucking Inc., 1999 WL 1087026, at *6 (D.V.I. Oct. 7, 1999) (excluding expert’s testimony where expert “expressed awareness of obvious alternative causes” yet “did not investigate any other possible causes”);

Reiff v. Convergent Technologies, 957 F. Supp. 573, 582-83 (D.N. J. 1997) (excluding expert’s testimony and granting summary judgment where expert failed to rule out alternative causes of plaintiff’s carpal tunnel syndrome)

Rutigliano v. Valley Bus. Forms, 929 F. Supp. 779, 787 (D.N.J. 1996) (excluding expert’s testimony and granting summary judgment where the “record is replete with evidence, including [the expert’s] own admissions, that [plaintiff’s] symptoms could be attributable to medical conditions other than formaldehyde sensitization”)

Diaz v. Matthey, Inc., 893 F. Supp. 358, 376-377 (D.N.J. 1995) (excluding testimony and granting summary judgment where expert failed to rule out alternative causes for plaintiff’s asthma) (Irenas, J.)

Wade-Greaux v. Whitehall Labs., Inc., 874 F. Supp. 1441 (D.V. I.), aff’d, 46 F.3d 1120 (3d Cir. 1994) (excluding testimony of expert who failed to rule out alternative causes of plaintiff’s birth defects)

FOURTH CIRCUIT

Westberry v. Gislaved Gummi AB, 178 F.3d 257, 262-263 (4th Cir. 1999) (“Differential diagnosis, or differential etiology, is a standard scientific technique of identifying the cause of a medical problem by eliminating the likely causes until the most probable one is isolated”)

Shreve v. Sears, Robuck & Co., 166 F. Supp. 2d 378, 397-98 (D. Md. 2001) (excluding testimony where expert failed to rule out other causes of plaintiff’s injury other than an alleged defect in snow thrower)

Fitzerald v. Smith & Nephew Richards, Inc., 1999 WL 1489199 (D. Md. Dec. 30, 1999) (excluding expert’s testimony and granting summary judgment where expert “failed to rule out what could have been another cause of [plaintiff’s] condition”)

Aldridge v. Goodyear Tire & Rubber Co., 34 F. Supp. 2d 1010, 1024 (D. Md. 1999), vacated on other grounds, 223 F.3d 263 (4th Cir. 2000) (excluding testimony of plaintiffs’ experts where they “failed to adequately address possible alternative causes of plaintiffs’ illnesses”)

Oglesby v. General Motors Corp., 190 F.3d 244, 250 (4th Cir. 1999) (affirming exclusion of testimony where “as a matter of logic, [the expert witness] could not eliminate other equally plausible causes” of cracked plastic inlet);

Driggers v. Sofamor, S.N.C., 44 F. Supp. 2d 760, 765 (M.D.N.C. 1998) (excluding expert’s testimony and granting summary judgment where “expert failed to rule out other possible causes of [plaintiff’s back] pain”);

Higgins v. Diversey Corp., 998 F. Supp. 598, 603 (D. Md. 1997), aff’d, 135 F.2d 769 (4th Cir. 1998) (excluding expert’s testimony that the accidental inhalation of a bleach caused plaintiff’s injuries, where expert “admit[ted] that he [could] not rule out several other possible causes”)

FIFTH CIRCUIT

Michaels v. Avitech, Inc., 202 F.3d 746, 753 (5th Cir. 2000) (excluding testimony when “plaintiff’s experts wholly fail[ed] to address and rule out the numerous other potential causes” of an aircraft disaster)

Black v Food Lion, Inc, 171 F3d 308 (5th Cir 1999) (expert witness, purporting to use a differential diagnosis, testified that plaintiff’s slip in the supermarket caused fibromyalgia, which is largely idiopathic) (“This analysis amounts to saying that because [the physician] thought she had eliminated other possible causes of fibromyalgia, even though she does not know the real ‘cause,’ it had to be the fall at Food Lion. This is not an exercise in scientific logic but in the fallacy of post-hoc propter-hoc reasoning, which is as unacceptable in science as in law.”)

Conger v. Danek Med., Inc., 1998 WL 1041331, at *5-6 (N.D. Tex. Dec. 14, 1998) (excluding expert’s testimony and granting summary judgment when expert “had not attempted to rule out [other potential sources] as causes for [plaintiff’s back] pain”);

Leigh v. Danek Med., Inc., 1998 WL 1041329, at *4-5 (N.D. Tex. Dec. 14, 1998) (excluding expert’s testimony and granting summary judgment where expert failed to rule out alternative causes of plaintiff’s back pain)

Bennett v. PRC Public Sector, 931 F. Supp. 484, 492 (S.D. Tex. 1996) (excluding testimony of expert who failed to consider and rule out alternative causes of plaintiff’s repetitive motion disorders)

SIXTH CIRCUIT

Nelson v. Tennessee Gas Pipeline Co., 1998 WL 1297690, at *6 (W.D. Tenn. Aug. 1, 1998) (excluding testimony of expert who “failed to engage in adequate techniques to rule out alternative causes and offers no good explanation as to why his opinion is nevertheless reliable in light of other potential causes of the alleged injuries”);

Downs v. Perstorp Components, 126 F. Supp. 2d 1090, 1127 (E.D. Tenn. 1999) (excluding expert testimony as to whether exposure to chemicals caused plaintiff’s injuries where expert failed to rule out alternative causes)

EIGHTH CIRCUIT

Jisa Farms, Inc. v. Farmland Indus., No. 4:99CV3294, 2001 U.S. Dist. LEXIS 26084 (D. Neb. 2001)

Thurman v. Missouri Gas Energy, 107 F. Supp. 2d 1046, 1058 (W.D. Mo. 2000) (expert’s opinion “that the pipeline failed because of corrosion” was excluded and summary judgment granted where expert reached the conclusion “without eliminating other causes”)

Bruzer v. Danek Med., Inc., 1999 WL 613329, at *8 (D. Minn. Mar. 8, 1999) (excluding expert’s testimony and granting summary judgment where expert did “not attempt to rule out any alternative potential causes for [plaintiff’s] continuing and increasing [back] pain”)

National Bank of Commerce v. Assoc. Milk Producers, 22 F. Supp. 2d 942, 963 (E.D. Ark. 1998), aff’d, 191 F.3d 858 (8th Cir.1999) (excluding testimony and granting summary judgment where expert did “not successfully rule out other possible alternative causes” for cancer)

TENTH CIRCUIT

In re Breast Implant Lit., 11 F. Supp. 2d 1217, 1234 (D. Colo. 1998) (excluding expert testimony where expert failed to “explain what alternative causes he considered, or how he ruled out other possible causes” of plaintiffs’ auto- immune disease)

Stover v. Eagle Products, 1996 WL 172972, at *11 (D. Kan. Mar. 19, 1996) (excluding testimony of expert who “[did] not explain in any meaningful detail how he [was] able to exclude the numerous multiple alternative causes” of injury to plaintiff’s dogs)

ELEVENTH CIRCUIT

Rink v. Cheminova, Inc., 400 F.3d 1286, 1295 (11th Cir. 2005) (“[I]n the context of summary judgment . . . differential diagnosis evidence by itself does not suffice for proof of causation.”)

STATE COURT CASES

Blanchard v. Goodyear Tire & Rubber Co.,  2011 Vt. 85, 30 A.3d 1271 (2011) (holding that plaintiff’s claim that his NHL was caused by benzene was not reliably supported by differential diagnosis when a large percentage of NHL cases have no known cause)

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Do English Judges Diss Epidemiology?

September 13th, 2013

As noted the other day, Claire McIvor, a senior lecturer, at the Birmingham Law School, has published an interesting U.K. perspective on the use of epidemiologic and statistical evidence in health-outcome litigation. See “Debunking some judicial myths about epidemiology and its relevance to UK tort law,” in 21 Med. Law Rev. (2013), in press.

Ms. McIvor criticizes one case in particular for what she argues is an inappropriate dismissal of epidemiologic evidence as presented by an epidemiologist. Novartis Grimsby Ltd. v. Cookson, [2007] EWCA Civ 1261.

The pursuer, Cookson, worked for Novartis Grimsby, at its factory that manufactured dyes, including azo dyes, from 1964, until 2001, when he developed bladder cancer.  Cookson also chose to be exposed to various carcinogens as a personal lifestyle; he smoked cigarettes, 1/2 to one pack per day, for about 20 years, before quitting around 1980.

Cookson sued Novartis on allegations that he was overexposed to various aromatic amines[1], some of which are known to cause bladder cancer.  Novartis had previously paid such claims, but it contested Mr. Cookson’s case because of its belief that his workplace exposures had not been excessive, and that his past smoking habit more likely explained his cancer.  Both sides called physician expert witnesses, urologists, who both agreed that smoking and the aromatic amines could cause bladder cancer, but disagreed as to what caused Mr. Cookson’s disease.

Given the contest on causation, the two urologists agreed that the input of an epidemiologist, jointly instructed, would be helpful.  Now how quaint is that, for both sides to agree upon an expert witness?  Most lawyers in the United States would think it malpractice to engage in such a practice.

Professor Ray Cartwright, an epidemiologist who had published on the causes of bladder cancer, was the jointly instructed witness. A PubMed search for articles written by Cartwright on bladder cancer is set out below, and suggests that he was an appropriate choice, ex ante, at any rate.

Cartwright reviewed the epidemiologic literature, including some of his own studies. Cartwright’s report disappointed the plaintiff, however, when he opined that the workplace aromatic amine exposure was slight and posed only a low risk compared to the smoking. In assessing Cookson’s workplace exposure, Cartwright relied upon the exposure estimates of the parties’ industrial hygienists, and based his causal attribution upon an assessment that exposures were low.  Later, when plaintiff’s counsel showed that Cartwright misinterpreted some of the exposure data, Cartwright revised his report, but maintained that Cookson’s cancer was caused by smoking.

Professor Cartwright’s misstep on exposure probably diminished the strength of his opinion in the eyes of the trial judge, who ruled for the plaintiff.  Ms. McIvor seems to believe that this ruling improperly elevated clinical testimony over epidemiologic testimony, and credited “personalized probabilities” of the plaintiff’s testifying urologist, who attributed the cancer 20–25% to smoking, versus 70–75% to workplace exposures, and who opined that the workplace more than doubled the risk level that Cookson would have had had he never worked at the Novartis factory.  Novartis Grimsby Ltd. at 48.

Novartis appealed, on grounds that included an allegation of error in equating fact of exposure with causation of the bladder cancer.  Speaking for a unanimous England and Wales Court of Appeal, Lady Justice Smith dismissed the appeal, including its challenge to the medical causation issues.  Contrary to Ms. McIvor, however, the appellate court’s decision gave due weight to the epidemiologist, but found that the epidemiologic evidence was accessible to, and interpretable by, the clinicians. Although neither the appellate decision nor McIvor reviewed the actual epidemiologic evidence, several studies suggest that the relative risks for benzidine-derived dyes are greater than for smoking, and especially the risk for former smokers.  The judicial decision flowed not from improvidently dismissing epidemiologic evidence, or testimony by an epidemiologist, but from relying upon epidemiologic evidence marshaled by the plaintiff, through his urologist.[2]

Both sides agreed that smoking could cause bladder cancer, but they also had to agree that the risk of bladder cancer wanes after smoking cessation. Unfortunately, the Court of Appeal did not review the evidence, but the Surgeon General’s Reports note that cessation reduces risk by half after only a few years.  Wynder and Stellman (1977) and Wynder and Goldsmith (1977) suggest that the risk returns to baseline after 15 years of abstinence.  A study by Cartwright himself suggested the return to baseline in six years, although other studies (by Iscovich; Howe; Vineis; Hartge; and Burch) suggested an initial decline, followed by a persistent increased risk even beyond 15 years of abstinence.

Lady Justice Smith declared herself perplexed by these data, which seemed to be at odds with the notion that bladder cancer develops after 20 or more years latency:

“I myself have found it hard to understand how the passage of time after stopping smoking could result in a reduced risk of developing the disease if the aetiology of the disease is that the cancer begins at the time of exposure but does not manifest itself until later. However, as I have said, this issue was not fully explored in evidence and both experts agreed that the risk of developing bladder cancer from smoking decreased after smoking ceased.”

Novartis Grimsby Ltd. at 45.

Clearly though, it was not helpful to have Cartwright contradicted by the data in his own study.  Although the higher aromatic amine exposures occurred early in the plaintiff’s work career, Cookson continued to have some exposure up until the time of his diagnosis in 2001.  Professor Cartwright may well have been further undermined by the lack of any “time windows” in the occupational epidemiology, which would have supported a similar argument of declining risk from the more intense occupational exposure in the 1960’s.  The absence of such evidence for benzidine, compared with the evidence of latency and post-cessation declining risk for smoking, clearly hurt the employer’s case.  This imbalance in the evidence clearly helps to explain and support the courts’ rejection of Cartwright’s testimony.

Given the epidemiologic evidence, it is not at all clear that the plaintiff’s testifying urologist’s opinion that smoking contributed 25%-30%, whereas aromatic amines contributed 70%-75%, was merely a subjective or personal probability.  Smoking is associated with a two- to three-fold increase in risk in prospective studies, but Cookson was 20 years post-cessation.  His aromatic amine dyestuff exposure, which carries a much higher relative risk for bladder cancer, continued through till the end of his work tenure.  See “Dyes metabolized to benzidine,” in IARC Monographs on the Evaluation of Carcinogenic Risks to Humans Volume 100F (WHO 2012).

Cookson’s bladder cancer might have been a “background” case, or a result of both smoking and aromatic amine exposure, or a result of one or the other contested causes.  There appeared to be no serious evidence of synergy.  Given the studies at issue, the plaintiff’s testifying urologist’s opinion may well have been a reasoned analysis of the epidemiologic evidence.  The epidemiologist’s opinion, on the other hand, was clearly undermined by the facts of smoking cessation, and an initial error in exposure estimation.  Novartis’ counsel argued that Cartwright was the “real expert” on the issue of attribution, but Cartwright’s opinion was lacking important foundational facts, and there was no argument that Mr. Barnard, the plaintiff’s urologist, had erred in interpreting the epidemiologic data.  Novartis Grimsby Ltd. at 56.  The real “expert” was in the data, and there was no showing (at least in the published opinion) that the clinician, Mr. Barnard, misunderstood or distorted the epidemiologic data.  In this respect, the Novartis Grimsby case is very different from the Milward case, in which a plaintiff’s toxicologist mistreated, misanalyzed, and misrepresented epidemiologic studies on benzene.

Lady Justice Smith rejected the appellant’s criticism of the trial judge’s weighting Mr. Barnard’s opinion over Professor Cartwright’s:

“The proposition that a clinician is not capable of fully understanding the published epidemiological literature on the causation of a condition within his own specialty seems unsustainable and would, I think, surprise many clinicians and epidemiologists. In my view, it was clear from his detailed reports on causation that Mr. Barnard was familiar with the published work and he was also able to discuss it intelligently when giving evidence. The Recorder was plainly of that view. As for the suggestion that Mr. Barnard was too ready to assume that working for the appellant created an increased risk, this was a good ‘jury point’ but, if it did not appeal to the Recorder, that was an end to it.”

Novartis Grimsby Ltd. at 57.

Although Ms. McIvor is correct to be concerned with the court’s eager over-generalization about the ability of clinicians to understanding of epidemiologic studies, there was little suggestion that Mr. Barnard had tripped up, and there was a good deal to suggest that Professor Cartwright’s opinion was lacking on essential issues.  Admittedly, this impression may have been created by selective reporting by the Court of Appeal.  I have not seen the record or the briefs, but Ms. McIvor has not cited anything from those sources.

Mr. Barnard, the plaintiff’s urologist, further testified that the “occupational exposure had more than doubled the risk due to smoking.”  Novartis Grimsby Ltd. at 53.  The Court of Appeal thus found it easy to affirm the verdict that Cookson had shown that his workplace exposure was the “but for” cause of his cancer.  Of course, the Court of Appeal here accepted evidence of risk and relative risk as showing causation, a dubious proposition. Novartis Grimsby Ltd. at 67. And the Court of Appeal, distinguishing a pneumoconiosis case, further pronounced that the bladder cancer injury was “indivisible,” and thus not capable of an apportionment because neither exposure could be said to make the disease more severe.  The Court could have said, if it yielded to its own risk as causation rationale, that both exposures made the cancer more likely, and the occupational exposure contributed to this overall risk three times as much as the plaintiff’s smoking.  In Justice Lady Smith’s words:

“The natural inference to draw from the finding of fact that the occupational exposure was 70% of the total is that, if it had not been for the occupational exposure, the respondent would not have developed bladder cancer. In terms of risk, if occupational exposure more than doubles the risk due to smoking, it must, as a matter of logic, be probable that the disease was caused by the former.”

Novartis Grimsby Ltd. at 74.

The Court of Appeal’s opinion was thus consistent with its own commitment to the conflation of risk with causation, a conflation that may well be objectionable, but does not seem to be the basis for Ms. McIvor’s objections to the Novartis decision.  Of course, a remand with directions to apportion would have a perfectly logical and consistent result with the insistence that risk be substituted for causation in supporting the verdict below.

Publications of Professor Cartwright on Bladder Cancer from National Library of Medicine Database

1: Subramonian K, Cartwright RA, Harnden P, Harrison SC. Bladder cancer in patients with spinal cord injuries. BJU Int. 2004 Apr;93(6):739-43. PubMed PMID: 15049983.

2: Cartwright RA. Bladder cancer screening in the United Kingdom. J Occup Med. 1990 Sep;32(9):878-80. PubMed PMID: 2074512.

3: Cuzick J, Babiker A, De Stavola BL, McCance D, Cartwright R, Glashan RW. Palmar keratoses in family members of individuals with bladder cancer. J Clin Epidemiol. 1990;43(12):1421-6. PubMed PMID: 2147716.

4: Philip PA, Fitzgerald DL, Cartwright RA, Peake MD, Rogers HJ. Polymorphic N-acetylation capacity in lung cancer. Carcinogenesis. 1988 Mar;9(3):491-3. PubMed PMID: 3345587.

5: Cartwright RA. Screening workers exposed to suspect bladder carcinogens. J Occup Med. 1986 Oct;28(10):1017-9. PubMed PMID: 3772536.

6: Boyko RW, Cartwright RA, Glashan RW. Bladder cancer in dye manufacturing workers. J Occup Med. 1985 Nov;27(11):799-803. PubMed PMID: 4067684.

7: Cartwright RA, Philip PA, Rogers HJ, Glashan RW. Genetically determined debrisoquine oxidation capacity in bladder cancer. Carcinogenesis. 1984 Sep;5(9):1191-2. PubMed PMID: 6467507.

8: Cartwright RA, Glashan RW. Palmar keratoses and bladder cancer. Lancet. 1984 Mar 10;1(8376):563. PubMed PMID: 6142276.

9: Cartwright RA, Adib R, Appleyard I, Glashan RW, Gray B, Hamilton-Stewart PA, Robinson M, Barham-Hall D. Cigarette smoking and bladder cancer: an epidemiological inquiry in West Yorkshire. J Epidemiol Community Health. 1983

Dec;37(4):256-63. PubMed PMID: 6655413; PubMed Central PMCID: PMC1052920.

10: Cartwright RA, Adib R, Appleyard I, Glashan RW, Richards B, Robinson MR, Sunderland E, Barham-Hall D. ABO, MNSs and rhesus blood groups in bladder cancer. Br J Urol. 1983 Aug;55(4):377-81. PubMed PMID: 6411162.

11: Cartwright RA, Adib R, Appleyard I, Coxon JG, Glashan RW, Richards B, Robinson MR, Sunderland E, Barham-Hall D. Ten genetic polymorphisms in bladder cancer. J Med Genet. 1983 Apr;20(2):112-6. PubMed PMID: 6221102; PubMed Central PMCID: PMC1049011.

12: Cartwright RA. Historical and modern epidemiological studies on populations exposed to N-substituted aryl compounds. Environ Health Perspect. 1983 Mar;49:13-9. PubMed PMID: 6339220; PubMed Central PMCID: PMC1569142.

13: Cartwright RA, Robinson MR, Glashan RW, Gray BK, Hamilton-Stewart P, Cartwright SC, Barham-Hall D. Does the use of stained maggots present a risk of bladder cancer to coarse fishermen? Carcinogenesis. 1983;4(1):111-3. PubMed PMID: 6821882.

14: Cartwright RA, Glashan RW, Rogers HJ, Ahmad RA, Barham-Hall D, Higgins E, Kahn MA. Role of N-acetyltransferase phenotypes in bladder carcinogenesis: a pharmacogenetic epidemiological approach to bladder cancer. Lancet. 1982 Oct 16;2(8303):842-5. PubMed PMID: 6126711.

15: Garner RC, Mould AJ, Lindsay-Smith V, Cartwright RA, Richards B. Mutagenic urine from bladder cancer patients. Lancet. 1982 Aug 14;2(8294):389. PubMed PMID: 6124790.

16: Cartwright R. Occupational bladder cancer and cigarette smoking in West Yorkshire. Scand J Work Environ Health. 1982;8 Suppl 1:79-82. PubMed PMID: 7100861.

17: Glashan RW, Cartwright RA. Occupational bladder cancer and cigarette smoking  in West Yorkshire. Br J Urol. 1981 Dec;53(6):602-4. PubMed PMID: 7317749.

18: Cartwright RA, Gadian T, Garland JB, Bernard SM. The influence of malignant cell cytology screening on the survival of industrial bladder cancer cases. J Epidemiol Community Health. 1981 Mar;35(1):35-8. PubMed PMID: 7264531; PubMed Central PMCID: PMC1052117.

19: Cartwright RA, Adib R, Glashan R, Gray BK. The epidemiology of bladder cancer in West Yorkshire. A preliminary report on non-occupational aetiologies. Carcinogenesis. 1981;2(4):343-7. PubMed PMID: 7273315.

20: Cartwright RA, Glashan RW, Gray B. Survival of transitional cell carcinoma cases in 2 Yorkshire centres. Br J Urol. 1980 Dec;52(6):497-9. PubMed PMID: 7459578.

21: Cartwright RA, Bernard SM, Glashan RW, Gray BK. Bladder cancer amongst dye users. Lancet. 1979 Nov 17;2(8151):1073-4. PubMed PMID: 91807.

22: Cartwright RA. Genetic association with bladder cancer. Br Med J. 1979 Sep 29;2(6193):798. PubMed PMID: 519209; PubMed Central PMCID: PMC1596415.

23: Williams DR, Cartwright RA. The esterase D polymorphism in patients with diabetes or carcinoma of the bladder and a matched sample of non-dono. Ann Hum Biol. 1978 May;5(3):281-4. PubMed PMID: 686669.

[1] α-naphthylamine, some of which was contaminated with β-napthylamine, benzidine, dianisidine and o-tolidine

[2] There was a suggestion that the plaintiff’s urologist had invoked his clinical experience in treating men from the factory with bladder cancer, but the courts did not seem to give dispositive weight to this irrelevant argument for causation. Novartis Grimsby Ltd. at 56.

Posted in Causation, Rule 702, Scientific Evidence | Comments Off on Do English Judges Diss Epidemiology?

Daubert Bewigged

September 11th, 2013

Claire McIvor, a senior lecturer, at the Birmingham Law School, has published an interesting U.K. perspective on the use of epidemiologic and statistical evidence in health-outcome litigation. See “Debunking some judicial myths about epidemiology and its relevance to UK tort law,” in 21 Med. Law Rev. (2013), in press.

McIvor argues that British judges have failed to engage with epidemiologic evidence, and have relegated epidemiologic evidence to a status inferior to clinical evidence, even when testifying clinicians have little to offer the fact finder.  If the be-wigged judges have done this shame on them, but McIvor suggests that a pre-trial hearing is necessary to address the proper (and improper) range of methodologies and inferences:

“The very fact that methodologically problematic evidence can end up before a trial court is indicative of the need for a pre-trial admissibility test for scientific evidence in UK civil law. Such a test would afford the court an opportunity to evaluate the scientific reliability of any epidemiological evidence that the parties wish to introduce at trial.”

McIvor at 22.  In advancing this recommendation, McIvor expands upon a recent Law Commission recommendation for what she describes as “a pre-trial admissibility test for scientific evidence in criminal litigation, similar to that which is used in the USA.”  McIvor at 32 (citing Law Commission, Expert Evidence in Criminal Proceedings in England and Wales (Law Comm’n No. 325, 2011)).

This recommendation and discussion, however, are confusing and perhaps confused.  The test in the United States is not a pre-trial test, although a party may ask for a determination in advance, either in conjunction with a motion for summary judgment, or to limit the evidentiary display at trial.   Nonetheless, objections to expert witness opinion testimony can certainly be made at trial.  Indeed, if the pre-trial motion is denied, the moving party may well have to renew its objection at trial in any event.

MacIvor’s recommendation is puzzling for other reasons.  First, most civil cases are tried to the bench, and the need to challenge the expert opinion pre-trial is certainly less pressing.  Lengthy, methodological challenges are virtually impossible before a jury but they would be made in front of the presiding judge, in any event.  Second, having recommended the pre-trial procedure, and the substantive standard for reliability and validity, McIvor proceeds to tell us that it [the Daubert standard] has “proven to be a rather controversial test in practice.”  Id. at 32 n.84 (citing no less of an authority than Carl Cranor, Toxic Torts: Science, Law and the Possibility of Justice 62-90 ( 2006)).  Cranor is hardly an unbiased, reliable source, but if McIvor accepts his pronouncements, her recommendation is hard to understand.  Third, McIvor gives us an example of a class of cases, which at first blush, suggest that judges on the other side of the Atlantic just do not understand science.  In McTear v. Imperial Tobacco, [2005] 2 SC 1, the trial judge, Lord Nimmo Smith, ruled in favor of a tobacco company in a lung cancer personal injury case.  His ruling was largely based upon a rejection of the epidemiologic evidence, which McIvor suggests is unreasonable, but then tells us that the rejection might have resulted from the plaintiffs’ reliance upon reports without the benefit of an epidemiologist to explain and teach the trial judge about the meaning of the evidence.

Indeed, McIvor tells us that Lord Nimmo Smith complained in his opinion that he had not been:

“‘sufficiently instructed by the expert evidence about this discipline’ to be able to form his own judgment of the evidence. This was not an unreasonable point, at least as regards the issue of individual causation.”

McIvor at 32 (quoting Lord Nimmo Smith).  Well, it does suggest that the good Lord may have been a stubborn Scot, who was not going to give any weight to the common wisdom, but rather insist that the plaintiff make his case in court.  Even McIvor goes on to characterize the plaintiff’s counsel’s strategy as “unwise, in hindsight.”  Id.

Rule 702 is an extremely important part of the law of evidence in federal courts, and in many state courts.  The U.K. would do well to adopt it, with allowance for the very different role of judges in civil cases on the other side of the Atlantic.

Posted in Rule 702, Scientific Evidence | Comments Off on Daubert Bewigged

Woodside & Davis on the Bradford Hill Considerations

August 23rd, 2013

Dr. Frank Woodside and Allison Davis have published an article on the so-called Bradford Hill criteria.  Frank C. Woodside, III & Allison G. Davis, “The Bradford Hill Criteria: The Forgotten Predicate,” 35 Thomas Jefferson L. Rev. 103 (2013).

Their short paper may be of interest to Rule 702 geeks, and students of how the law parses causal factors in litigation.

The authors argue that a “predicate” to applying the Hill criteria consists of:

  • ascertaining a clear-cut association,
  • determining the studies establishing the association are valid, and
  • satisfying the Daubert [1][sic] requirements.

Id. at 107.  Parties contending for a causal association often try to flyblow the need for statistical significance at any level, and argue that Bradford Hill did not insist upon statistical testing.  Woodside and Davis remind us that Bradford Hill was quite firm in insisting upon the need to rule out random variability as an explanation for an association:

“Our observations reveal an association between two variables, perfectly clear-cut and beyond what we would care to attribute to the play of chance.”

Id. at 105; see Hill, Austin Bradford Hill, “The Environment and Disease: Association or Causation?” 58 Proc. Royal Soc’y Med. 295 (1965).  The authors correctly note that the need for study validity is fairly implied by Bradford Hill’s casual expression about “perfectly clear-cut.”

Woodside and Davis appear to acquiesce in the plaintiffs’ tortured interpretation of Bradford Hill’s speech, on which statistical significance supposedly is unimportant.  Woodside & Davis at 105 & n.7 (suggesting that Bradford Hill “seemingly negates the second [the requirement of statistical significance] when he discounts the value of significance testing, citing Bradford Hill at 299).

Woodside and Davis, however, miss the heavy emphasis that Bradford Hill actually placed upon “tests of significance”:

“No formal tests of significance can answer those questions. Such tests can, and should, remind us of the effects that the play of chance can create, and they will instruct us in the likely magnitude of those effects. Beyond that they contribute nothing to the ‘proof’ of our hypothesis.”

Bradford Hill at 299.  Bradford Hill never says that statistical tests contribute nothing to proving an hypothesis; rather, his emphasis is on the insufficiency of statistical tests alone to establish causality.  Bradford Hill’s “beyond that” language clearly stakes out the preliminary, but necessary importance of ruling out the play of chance before proceeding to consider the causal factors.

Passing beyond their exegetical fumble, Woodside and Davis proceed to discuss the individual Bradford Hill considerations and how they have fared in the crucible of Rule 702.  Their discussion may be helpful to lawyers who want to track the individual considerations, and how they have treated, or dismissed, by trial courts charged with gatekeeping expert witness opinion testimony.

There is another serious problem in the Woodside and Davis paper.  The authors describe risk ratios and the notion of “confidence intervals”:

“A confidence interval provides both the relative risk found in the study and a range (interval) within which the risk would likely fall if the study were repeated numerous times.32 … As such, risk measures used in conjunction with confidence intervals are critical in establishing a perfectly clear-cut association when it comes to examining the results of a single study.35”

Woodside & Davis at 110.  The authors cite to the Reference Manual on Scientific Evidence (3d 2011), but they fail to catch important nuances of the definition of a confidence interval.  The obtained interval from a given study is not the interval within which the “risk would likely fall if the study were repeated… .”  Rather it is 95% of the many intervals, from the many repeated studies done on the same population, with the same sample size, which would capture the true risk.  As for the obtained interval, the true risk is either within it, or not, and no probability value attaches to the likelihood that the true value lies within the obtained interval.

It is a mystery why lawyers would bother to define something like the confidence interval, and then do it incorrectly.  Here is how Professors Finkelstein and Levin define the confidence interval in their textbook on statistics:

“A confidence interval for a population proportion P is a range of values around the proportion observed in a sample with the property that no value in the interval would be considered unacceptable as a possible value for P in light of the sample data.”

Michael Finkelstein & Bruce Levin, Statistics for Lawyers 166-67 (2d ed. 2001).   This text explains why and where Woodside and Davis went astray:

“It is the confidence limits PL and PU that are random variables based on the sample data. Thus, a confidence interval (PL, PU) is a random interval, which may or may not contain the population parameter P. The term “confidence” derives from the fundamental property that, whatever the true value of P, the 95% confidence interval will contain P within its limits 95% of the time, or with 95% probability. This statement is made only with reference to the general property of confidence intervals and not to a probabilistic evaluation of its truth in any particular instance with realized values of PL and PU.”

Id. at 167-71.

[1] Surely the time has come to stop referring to the Daubert factors and acknowledge that the Daubert case was just one small step in the maturation of evidence law.  The maturation consisted of three additional Supreme Court cases, many lower court cases, and a statutory revision to Federal Rule of Evidence 702, in 2000.  The Daubert factors hardly give due consideration to the depth and breadth of the law in this area.

Posted in Causation, Rule 702, statistical evidence | Comments Off on Woodside & Davis on the Bradford Hill Considerations

THE COUNCIL FOR EDUCATION AND RESEARCH ON TOXICS

July 9th, 2013

When the Milward case hit the U.S. Court of Appeals for the First Circuit, it attracted the attentions of an amicus, the Council for Education and Research on Toxics (CERT).  I had never heard of CERT before, and the amicus brief filed by CERT was rather sketchy on the nature of the organization.

A bit of research on CERT revealed the following.  It is a non-profit California corporation, EIN: 42-1571530, founded in 2003.  CERT has a business address at:

401 E Ocean Blvd., Ste. 800, Long Beach, California 90802-4967

And a telephone number:  1-877-TOX-TORT

CERT’s mission statement? Furthering scientific understanding of toxins.

Plaintiffs’ lawyer Ralph Metzger is noted as the contact person for CERT.

Given its phone number and its contact person, one might think that its mission statement was “furthering legal positions on toxins.”

But wait; it gets better.  Ralphael Metzger, at the same Long Beach, California, address is the attorney for CERT on its amicus brief in Milward!

The potential conflicts grow deeper and wider.  Metzger has represented CERT, which shares at least his offices, if not his alter ego, in lawsuits including CERT v. Brad Berry Co., Ltd., No. BC461182 (Cal. Super. Ct., Los Angeles County, Cent. Dist., filed May 9, 2011), and CERT v. Starbucks Corp., BC435759 (L.A. Super. Ct., filed April 13, 2010).

CERT has sued McDonald’s and Burger King over its claim that their french fries contained high levels of acrylamide, a chemical “known” to the State of California to cause cancer. CERT has sued Chemtura on claims that the company’s chemical fire-preventive products, known as PBDEs, cause injuries to wildlife and humans.

Although not definitive, it seems that CERT’s mission is not exactly scientific, and the description of its interests in its Milward brief just a tad misleading.

In addition to the CERT, the other amici joining the brief include:

Nicholas A. Ashford,
Nachman Brautbar,
David C. Christiani,
Richard W. Clapp,
James Dahlgren,
Devra Lee Davis,
Malin Roy Dollinger,
Brian G. Durie,
David A. Eastmond,
Arthur L. Frank,
Frank H. Gardner,
Peter L. Greenberg,
Robert J. Harrison,
Peter F. Infante,
Philip J. Landrigan,
Barry S. Levy,
Melissa A. McDiarmid,
Myron Mehlman,
Ronald L. Melnick,
Mark Nicas,
David Ozonoff,
Stephen M. Rappaport,
David Rosner,
Allan H. Smith,
Daniel Thau Teitelbaum,
Janet Weiss, and
Luoping Zhang

An interesting bunch; eh?  Page two of the amicus brief tells us that:

“None of the amici has any financial or other similar interest in the outcome of this lawsuit. Amici appear on their own behalf to inform this Court of the substantial medical knowledge and understanding of leukemia arising from exposure to benzene.”

That’s probably true for the Milward case itself, but more interesting for what the disclosure does not say.  Many of the amici have testified frequently in toxic tort cases, and several have been excluded by the straightforward application of Rule 702 or its state counterparts.  Some have lost income as a result of judicial gatekeeping, and most have seen their advocacy science curtailed by such gatekeeping.

Appendix I to the brief provides further information on the amici, but there is no mention of their testimonial adventures, their financial stake in expert witnessing, or their political or positional commitments.

I suppose from CERT you get CERT-i-tude, a certain kind of attitude.

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Sympathy for the Diablo — Peppermint Barry vs Spicy Seafood Pasta

June 12th, 2013

Barry S. Levy is a physician, author, performer, and political activist.   Dr. Levy is a past president of the American Public Health Association, which conferred upon him its oldest and most prestigious award, the Sedgwick Memorial Medal, in 2005, for his outstanding achievements in public health.

Levy has been received other, less favorable notice from trial and appellate judges.  For instance, one federal judge found Levy engaged in a dubious enterprise to manufacture silicosis claims in Mississippi.  In re Silica Products Liability Litigation, 398 F. Supp. 2d 563, 611-16, 622 & n.100 (S.D. Texas 2005) (expressing particular disappointment with Dr. Barry Levy, who although not the worst offender of a bad lot of physicians, betrayed his “sterling credentials” in a questionable enterprise to manufacture diagnoses of silicosis for litigation). See also Schachtman, Silica Litigation: Screening, Scheming & Suing; Washington Legal Foundation Critical Legal Issues Working Paper Series No. 135 (Dec. 2005) (exploring the ethical and legal implications of the entrepreneurial litigation in which Levy and others were involved).

Unfortunately, In re Silica was not an isolated case.  See, e.g., Lofgren v. Motorola, Inc., 1998 WL 299925, No. CV 93-05521 (Ariz. Super. Ct., Maricopa Cty. June 1, 1998); Harman v. Lipari, N.J. L. Div. GLO-L-1375-95, Order of Nov. 3, 2000 (Tomasello, J.) (barring the use of Barry Levy in class action for medical monitoring damages); Castellow v. Chevron USA, 97 F.Supp. 2d 780, 793-95 (S.D. Tex. 2000); Knight v. Kirby Inland Marine Inc., 482 F.3d 347 (5th Cir. 2007); Watts v. Radiator Specialty Co., 990 So. 2d 143 (Miss. 2008); Aurand v. Norfolk So. Ry., 802 F.Supp.2d 950 (2011).

Now, once again, right here in River City, Dr. Levy has stepped out of bounds, and has been stripped of his mantle of testifying expert witness.  Mallozzi v. Ecosmart Technologies, Inc., 2013 WL 2415677, No. 11-CV-2884 (SJF)(ARL) (E.D.N.Y. May 31, 2013).

Over the course of a few minutes, plaintiff Velio Mallozi applied a “couple of ounces” of EcoSmart Organic Home Pest Control product to the foundation of his home, and a few squirts inside.  The product used, EcoSmart, contains plant oils, including one percent peppermint oil.  Id. at *1.  Mallozi did not experience any acute ill effects from his organic pest control efforts, and later went to dinner at an [unidentified] Italian restaurant, where he enjoyed a meal of “spaghetti with seafood.”  Id. at *10.  Perhaps seafood diablo, but Judge Feuerstein doesn’t say.

After the seafood spaghetti meal, Mallozi experienced a serious bout of laryngopharyngeal reflux (LPR).  With sympathy for the diablo, Mallozi sued only EcoSmart, on the claim that his inhaling some spray, with its 1% peppermint oil, caused his LPR.

The Mallozis sought out B.S. Levy to support the claimed relationship.  Levy did not disappoint.  He rendered a report that asserted that the few minutes of inhaling minor amounts of peppermint oil causes relaxation of the lower esophogeal sphincter, and consequently LPR.  Id. at *5.  Levy relied upon four articles to support this claim, but Judge Feuerstein refused to accept the claim of support, at face value.  Her Honor reviewed each study, only to find that the exposures that were associated with relaxation of G.I. smooth muscle, for a short period of about 20 minutes, were trials of ingested peppermint oil, at significantly greater doses, over lengthy periods of observation.  Id. at *6.  The studies individually and collectively did not support Levy’s opinion.

One of the papers on Levy’s reliance list was a case report of a patient that suffered burns in her mouth from ingestion of pure peppermint oil. The court found that this case report, involving large doses of pure peppermint oil, with an outcome different from claimed by Mallozi, was irrelevant.  Id. Even if it were construed to offer some support, the anecdotal nature of the case report, lacking controls, renders the report an unreliable basis for a causal conclusion.  Id.

The trial court found that B.S. Levy’s analysis ignored the crucial roles of dose, duration, route of exposure, and the nature of plaintiff’s condition, LPR.   Id. at *8.  The court held that Levy’s opinion did not satisfy the requirements of Rule 702.  The plaintiffs failed to show that Levy’s opinion was supported sufficiently by facts or data, and they failed to show that his opinion was the product of applying reliable methods and principles.  Id.

Judge Feuerstein, having found that Levy’s opinion on general causation between EcoSmart and LPR was bereft of validity, could have stopped without addressing specific causation.  Such an approach would have had the virtue of judicial economy, but would have left out some delicious facts.  Levy purportedly used some sort of differential etiology to infer the cause of plaintiff’s LPR, but he omitted meaningful consideration of plaintiff’s having had a history of severe severe gastroesophageal reflux disease (GERD), which predated his bout of LPR.  Indeed, plaintiff’s GERD had been so severe that he had been previously hospitalized for GERD after ingesting coffee and donuts.   Judge Feuerstein found Levy’s iterative disjunctive syllogism invalid for having failed to address the prior history of GERD, and the intervening role of the pasta and seafood dinner, in bringing on the LPR.  Id. at *10-11.

The Material Safety Data Sheet Ploy

Judge Feuerstein also demonstrated a careful understanding of the meaning and role of the Material Data Safety Sheet (MSDS).  EcoSmart’s MSDS contained a warning that some sensitive persons may experience dizziness or irritation of their nasal passages, and that ingestion may cause GI irritation.  Id. at *13.  Dr. Levy had embraced this MSDS language as an “admission,” but he did not analyze the sources of information or their validity.  The MSDS warning, as required by law, addresses the potential hazard of the ingredient, peppermint oil, irrespective of dose, concentration, or route of administration.  Id., citing Moore v. Ashland Chem. Inc., 151 F.3d 269, 278 (5th Cir.1998); Turner v. Iowa Fire Equip. Co., 229 F.3d 1202, 1209 (8th Cir.2000); Ingram v. Solkatronic Chem., Inc., No. 04–CV–0287, 2005 WL 3544244, at *6 (N.D.Okla. Dec. 28, 2005)).

The Treating Physician Echo

Apparently one of Mr. Mallozzi’s treating physicians joined the fray with echoes of Levy’s opinion.  Judge Feuerstein recognized that treating physicians are subject to the requirements of Rule 702, and that a me-too opinion deserved the me-too result.  Id. at *13, citing Davids v. Novartis Pharm. Corp., 857 F.Supp. 2d 267, 280 (E.D.N.Y. 2012).

Pasta and Peppermints

Bad sense, innocence, cripplin’ my mind.
Old medical records I just can’t find.
Too much Cajun spice, and I forgot about GERD.
Incense and peppermints, haven’t you heard?
But who cares, it’s just litigation.
Lots to win, but nothing to lose.

Incense and peppermints, meaningless claims.
Turn on, drop in, toxins are all the same

Throw your pride to the side; it’s what you must do.

Daubert is politics; 702.
A yardstick for lunatics, your point of view.
The court cares what games you choose.
You have lots to win, but nothing to lose

(adapted from, and with apologies to, Strawberry Alarm Clock)

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