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Vaccine Court Inoculated Against Pathological Science

October 25th, 2015

Richard I. Kelley, M.D., Ph.D., is the Director of the Division of Metabolism, Kennedy Krieger Institute, and a member of the Department of Pediatrics, in Johns Hopkins University. The National Library of Medicine’s Pubmed database shows that Dr. Kelley has written dozens of articles on mitochondrial disease, but none that concludes that thimerosal or the measles, mumps and rubella vaccine plays a causal role in causing autism by inducing or aggravating mitochondrial disease. In one article, Kelley opines:

“Large, population-based studies will be needed to identify a possible relationship of vaccination with autistic regression in persons with mitochondrial cytopathies.”

Jacqueline R. Weissman, Richard I. Kelley, Margaret L. Bauman, Bruce H. Cohen, Katherine F. Murray, Rebecca L. Mitchell, Rebecca L. Kern, and Marvin R. Natowicz, “Mitochondrial Disease in Autism Spectrum Disorder Patients: A Cohort Analysis,” 3 PLoS One e3815 (Nov. 26, 2008). Those large scale population-based studies to support the speculation of Kelley and his colleagues have not materialized since 2008, and meta-analyses and systematic reviews have dampened the enthusiasm for Kelley’s hypothesis.[1]

Special Master Denise K. Vowell, in the Federal Court of Claims, has now further dampened the enthusiasm for Dr. Kelley’s mitochondrial theories, in a 115 page opinion, written in support of rejecting Kelley’s testimony and theories that the MMR vaccine caused a child’s autism. Madariaga v. Sec’y Dep’t H.H.S., No. 02-1237V (Ct. Fed. Claims Sept. 26, 2015) Slip op. [cited as Madariaga].

Special Master Vowell fulsomely recounts the history of vaccine litigation, in which the plaintiffs have presented theories that the combination of thimerosal-containing vaccines and the MMR vaccine cause autism, or just the thimerosal-containing vaccines cause autism. Madariaga at 3. Both theories were tested in the crucible of litigation and cross-examination in a series of test cases. The first theory resulted in verdicts against the claimants, which were affirmed on appeal.[2] Similarly, the trials on the thimerosal-only claims uniformly resulted in decisions from the Special Masters against the claims.[3] The three Special Masters, hearing the cases, found that the vaccine-causation claims were not close cases, and were based upon unreliable evidence.[4] Madariaga at 4.[5]

In Madariaga, Special Master Vowell noted that Doctor Kelley had conceded the “absence of an association between the MMR vaccine and autism in large epidemiological studies.” Madariaga at 61. Kelley attempted to evade the force of his lack of evidence by retreating into a claim that “autistic regressions caused by the live attenuated MMR vaccine are rare events,” and an assertion that there are many inflammatory factors that can induce autistic regression. Madariaga at 61.

Special Master described the whole of Kelley’s testimony as “meandering, confusing, and completely unpersuasive elaboration of his unique insights and methods.” Madariaga at 66. Although it is clear from the Special Master’s opinion that Kelley was unbridled in his over-interpretation of studies, and perhaps undisciplined in his interpretation of test results, the lengthy opinion provides only a high-altitude view of Kelley’s errors. There are tantalizing comments and notes in the Special Master’s decision, such as one that reports that one study may have been over-interpreted by Kelley because he ignored the authors’ comment that their findings could be consistent with chance because of their multiple comparisons, and another that paper that failed to show statistical significance. Madariaga at 90 & n.160.

The unreliability of Kelley’s testimony appeared to be more than hand waving in the absence of evidence. He compared the child’s results on a four-hour fasting test, when the child had not fasted for four hours. When pressed about this maneuver, Kelley claimed that he had made calculations to bring the child’s results “back to some standard.” Madariaga at 66 & n.115.

Although the Special Master’s opinion itself was ultimately persuasive, the tome left me eager to know more about Dr. Kelley’s epistemic screw ups, and less about vaccine court procedure.

[1] See Vittorio Demicheli, Alessandro Rivetti, Maria Grazia Debalini, and Carlo Di Pietrantonj, “Vaccines for measles, mumps and rubella in children,” Cochrane Database Syst. Rev., Issue 2. Art. No. CD004407, DOI:10.1002/14651858.CD004407.pub3 (2012) (“Exposure to the MMR vaccine was unlikely to be associated with autism … .”); Luke E. Taylor, Amy L. Swerdfeger, and Guy D. Eslick, “Vaccines are not associated with autism: An evidence-based meta-analysis of case-control and cohort studies,” 32 Vaccine 3623 (2014) (“Findings of this meta-analysis suggest that vaccinations are not associated with the development of autism or autism spectrum disorder. Furthermore, the components of the vaccines (thimerosal or mercury) or multiple vaccines (MMR) are not associated with the development of autism or autism spectrum disorder.”).

[2] Cedillo v. Sec’y, HHS, No. 98-916V, 2009 WL 331968 (Fed. Cl. Spec. Mstr. Feb. 12, 2009), aff’d, 89 Fed. Cl. 158 (2009), aff’d, 617 F.3d 1328 (Fed. Cir. 2010); Hazlehurst v. Sec’y, HHS, No. 03-654V, 2009 WL 332306 (Fed. Cl. Spec. Mstr. Feb. 12, 2009), aff’d, 88 Fed. Cl. 473 (2009), aff’d, 604 F.3d 1343 (Fed. Cir. 2010); Snyder v. Sec’y, HHS, No. 01-162V, 2009 WL 332044 (Fed. Cl. Spec. Mstr. Feb. 12, 2009), aff’d, 88 Fed. Cl. 706 (2009).

[3] Dwyer v. Sec’y, HHS, 2010 WL 892250; King v. Sec’y, HHS, No. 03-584V, 2010 WL 892296 (Fed. Cl. Spec. Mstr. Mar. 12, 2010); Mead v. Sec’y, HHS, 2010 WL 892248.

[4] See, e.g., King, 2010 WL 892296, at *90 (emphasis in original); Snyder, 2009 WL 332044, at *198.

[5] The Federal Rule of Evidence technically do not control the vaccine court proceedings, but the Special Masters are bound by the requirement of Daubert v. Merrell Dow Pharm., 509 U.S. 579, 590 (1993), to find that expert witness opinion testimony is reliable before they consider it. Knudsen v. Sec’y, HHS, 35 F.3d 543, 548-49 (Fed. Cir. 1994). Madariaga at 7.

Posted in Causation, Expert Witnesses, Rule 702, Scientific Evidence | Comments Off on Vaccine Court Inoculated Against Pathological Science

On Amending Rule 702 of the Federal Rules of Evidence

October 17th, 2015

No serious observer or scholar of the law of evidence can deny that the lower federal courts have applied Daubert and its progeny, and the revised Federal Rule of Evidence 702, inconstantly and inconsistently, in their decisions to admit or exclude proffered expert witness opinion testimony. Opponents of trial court “gatekeeping” of expert witnesses applaud the lapses in hopes that the gates have been unhinged and that there will be “open admissions” for expert witness testimony. These opponents latch on to the suggestion that the Rules favor “liberal” admissibility with a libertine; they lose sight of the meaning of “liberal” that conveys enlightened, with an openness to progress and salutary change, and the claims of knowledge over blind faith.  Supporters of gatekeeping lament the courts’ inability or unwillingness to apply a clear statutory mandate that is designed to improve and ensure the correctness of fact finding in the federal courts. A few have decried the lawlessness of the courts’ evasions and refusals to apply Rule 702’s requirements.

Given the clear body of Supreme Court precedent, and the statutory revision to Rule 702, which was clearly designed to embrace, embody, enhance, and clarify the high Court precedent, I did not think that an amendment to Rule 702 was needed to improve the sorry state of lower court decisions. Professor David Bernstein and lawyer Eric Lasker, however, have made a powerful case for amendment as a way of awakening and galvanizing federal judges to their responsibilities under the law. David E. Bernstein & Eric G. Lasker,“Defending Daubert: It’s Time to Amend Federal Rule of Evidence 702,” 57 William & Mary L. Rev. 1 (2015) [cited below as Bernstein & Lasker].

Bernstein and Lasker remind us that Rule 702 is a statute[1] that superseded inconsistent prior judicial pronouncements. The authors review many of the more egregious cases that ignore the actual text of Rule 702, while adverting to judicial gloss on the superseded rule, and even to judicial precedent and dicta pre-dating the Daubert case itself. Like the Papa Bear in the Berenstain Bear family, the authors show us how not to interpret a statute properly, through examples from federal court decisions.

The Dodgers’ Dodges

Questions about whether expert witnesses properly applied a methodology to the facts of a case are for the jury, and not the proper subject of gatekeeping.

As Bernstein and Lasker document, this thought- and Rule-avoidance dodge is particularly shocking given that the Supreme Court clearly directed close and careful analysis of the specific application of general principles to the facts of a case.[2] Shortly after the Supreme Court decided Daubert, the Third Circuit decided a highly influential decision in which it articulated the need for courts to review every step in expert witnesses’ reasoning for reliability. In re Paoli RR Yard PCB Litig., 35 F.3d 717, 745 (3d Cir. 1994). The Paoli case thus represents the antithesis of a judicial approach that asks only the 10,000 foot level question whether the right methodology was used; Paoli calls for a close, careful analysis of the application of a proper methodology to every step in the case. Id. (“any step that renders the analysis unreliable … renders the expert’s testimony inadmissible … whether the step completely changes a reliable methodology or merely misapplies that methodology”).

While the Paoli approach is unpopular with some judges who might prefer not to work so hard, the Advisory Committee heartily endorsed Paoli’s “any step” approach in its Note to the 2000 amendment. Bernstein & Lasker at 32. Bernstein and Lasker further point out that the Committee’s Report, Professor Dan Capra, acknowledged, shortly after the amendment went into effect, that the Paoli “any step” approach had a “profound impact” on the drafting of amended Rule 702. Bernstein & Lasker at 28.[3]

Having demonstrated the reasons, the process, and the substance of the judicial and legislative history of the revised Rule 702, Bernstein and Lasker are understandably incensed at the lawlessness of circuit and trial courts that have eschewed the statute, have ignored Supreme Court precedent, and have retreated to vague judicial pronouncements that trace back to before some or any of the important changes occurred in Rule 702.[4]

Let’s Cherry Pick and Weigh of the Evidence; Forget the Scale

Along with some courts’ insistence that trial judges may not examine the application of methods to the facts of a case, other courts, perhaps mindful of their citation practices, have endorsed “cherry picking” as a satisfactory methodology for partial expert witnesses to support their opinions. Id. at 35-36. Our law review authors also trace the influence of plaintiffs’ counsel, through their “walking around money” from the breast implant litigation, in sponsoring anti-Daubert, anti-gatekeeping conferences, at which prominent plaintiffs’ advocates and expert witnesses, such as Carl Cranor presented in favor of a vague “weight of the evidence” (WOE) approach to decision making. Id. at 39. Following these conferences, some courts have managed to embrace WOE, which is usually packaged as an abandonment of scientific standards of validity and sufficiency, in favor of selective review and subjective decisions. To do this, however, courts have had to ignore both Supreme Court precedent and the clear language of Rule 702. In Joiner, the high Court rejected WOE, over the dissent of a single justice,[5] but some of the inferior federal courts have embraced the dissent to the exclusion of the majority’s clear holding, as well as the incorporation of that holding into the revised Rule 702.[6] An interesting case of judicial disregard.

Other Dodges

The law review authors did not purport to provide an exhaustive catalogue of avoidance and evasion techniques. Here is one that is not discussed: shifting the burden of proof on admissibility to the opponent of the expert witness’s opinion:

“Testimony from an expert is presumed to be helpful unless it concerns matters within the everyday knowledge and experience of a lay juror.”

Earp v. Novartis Pharms., No. 5:11–CV–680–D, 2013 WL 4854488, at *3 (Sept. 11, 2013). See also Kopf v. Skyrm, 993 F.2d 374, 377 (4th Cir.1993); accord Koger v. Norfolk S. Ry. Co., No. 1:08–0909, 2010 WL 692842, at *1 (S.D.W.Va. Feb. 23, 2010) (unpublished).

Whence comes this presumption? Perhaps it is no more than a requirement for the opponent to object and articulate the flaws before the trial court will act. But the “presumption” sure looks like a covert shifting of the burden of proof for the requisite reliability of an expert witness’s opinion, which burden clearly falls on the proponent of the testimony.

The Proposed Amended Rule 702

There are several possible responses to the problem of the judiciary’s infidelity to basic principles, precedent, and legislative directive. Bernstein and Lasker advance amendments to the current Rule 702, as a blunt reminder that the times and the law have changed, really. Here is their proposed revision, with new language italicized, and deleted language shown to be struck:

“Rule 702. Testimony by Expert Witnesses

A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if the testimony satisfies each of the following requirements:

(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 that reliably support the expert’s opinion;

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

(d) the expert has reliably applied the principles and methods to the facts of the case and reached his conclusions without resort to unsupported speculation.

Appeals of district court decisions under this Rule are considered under the abuse-of-discretion standard. Such decisions are evaluated with the same level of rigor regardless of whether the district court admitted or excluded the testimony in question. This Rule supersedes any preexisting precedent that conflicts with any or all sections of this Rule.”

Bernstein & Lasker at 44-45.

Before discussing and debating the changes, we should ask, “why change a fairly good statute just because lower courts evade its terms?” The corrupt efforts of SKAPP[7] to influence public and judicial policy, as well as the wildly one-sided Milward symposium,[8] which the authors discuss, should serve as a potent reminder that there would be many voices in the review and revision process, both from within plaintiffs’ bar, and from those sympathetic to the litigation industry’s goals and desires. Opening up the language of Rule 702 to revision could result in reactionary change, driven by the tort bar’s and allies’ lobbying. The result could be the evisceration of Rule 702, as it now stands. This danger requires a further exploration of alternatives to the proposed amendment.

Rule 702 has had the benefit of evolutionary change and development, which have made it better and also possibly burdened with vestigial language. To be sure, the rule is a difficult statute to draft, and while the authors give us a helpful start, there is many problems to be subdued before a truly workable working draft can be put be forward.

The first sentence’s new language, “the testimony satisfies each of the following requirements,” is probably already satisfied the use of “and” between the following numbered paragraphs. Given the judicial resistance to Rule 702, the additional verbiage could be helpful; it should be unnecessary. The conditionality of “if,” however, leaves the meaning of the Rule unclear when that condition is not satisfied. The Rule clearly signifies that “if” in the introductory sentence means “only if,” and the law and litigants would be better off if the Rule said what it means.

Proposed Subsection (b)

(b) the testimony is based on sufficient facts or data that reliably support the expert’s opinion;

The authors do not make much of a case for striking “sufficient.” There will be times when there are perfectly good facts and data supporting an expert witness’s opinion, in a completely reliable opinion, but the supporting facts and data do not support an epistemic claim of “knowledge,” because the support is indeterminate between the claim and many other competing hypotheses that might explain the outcome at issue. The reliably supporting facts and data may amount to little more than a scientific peppercorn, and really be too much of too little to support the claim. Deleting “sufficient” from subsection b could be a serious retrograde move, which will confuse the judiciary more than instruct it.

The revised subsection also fails to address the integrity of the facts and data, and the validity of how the data were generated. To be sure, Rule 703 could pick up some of the slack, but Rule 703 is often ignored, and even when invoked, that rule has its own drafting and interpretation problems. See “Giving Rule 703 the Cold Shoulder” (May 12, 2012); “RULE OF EVIDENCE 703 — Problem Child of Article VII” (Sept. 19, 2011). Also missing is an acknowledgment that the facts or data must often be analyzed in some way, whether by statistical tests or some other means. And finally, there is the problem in that reliable does not necessarily connote valid or accurate. Subsection (b) thus seems to cry out for additional qualification, such as:

“the testimony is based on sufficient facts or data, reliably, accurately, and validly ascertained, and analyzed, which facts or data reliably and validly support the expert’s opinion”

Proposed Subsection (c)

Bernstein and Lasker propose modifying this subsection to inject “and objectively reasonable” before “principles and methods.” The authors do not explain what objectively reasonable principles and methods encompass, and they qualification does seem self-explanatory. Perhaps they are calling for principles and methods that are “generally accepted,” and otherwise justified as warranted to produce accurate, true results? Is so, that might be a helpful addition.

Proposed Subsection (d)

Here the authors bolster the language of the subsection with a prohibition against using unsupported speculation. OK; but would supported or inspired or ingenious speculation be any better? Subsection (a) speaks of knowledge, and it should be obvious that the expert witness’s opinion has an epistemic warrant to be something more than a mere subjective opinion.

Whether Bernstein and Lasker have opened a can or a Concordat of Worms remains to be seen.

[1] The authors provide a great resource on the legislative history of attempts to revise 702, up to and including the 2000 revision. The 2000 revision began with a proposed amendment from the Advisory Committee in April 1999. The Standing Committee on Rules of Practice and Procedure approved the proposal, and forwarded the proposed amendment to the Judicial Conference, which approved the amendment without change in September 1999. The Supreme Court ordered the amendment in April 2000, and submitted the revised rule to Congress. Order Amending the Federal Rules of Evidence, 529 U.S. 1189, 1195 (2000). The revised Rule 702 became effective on December 1, 2000. See also Bernstein & Lasker at 19 n. 99 (citing Edward J. Imwinkelried, “Response, Whether the Federal Rules of Evidence Should Be Conceived as a Perpetual Index Code: Blindness Is Worse than Myopia,” 40 Wm. & Mary L. Rev. 1595, 1595-98 (1999) (noting and supporting the Supreme Court’s interpretation and application of the Federal Rules of Evidence as a statute, and subject to the judicial constraints on statutory construction). For a strident student’s pro-plaintiff view of the same legislative history, see Nancy S. Farrell, “Congressional Action to Amend Federal Rule of Evidence 702: A Mischievous Attempt to Codify Daubert v. Merrell Dow Pharmaceuticals, Inc.”, 13 J. Contemp. Health L. & Pol’y 523 (1997).

[2] General Electric Co. v. Joiner, 522 U.S. 136 (1997) (reviewing and analyzing individual studies’ internal and external validity, and rejecting plaintiffs’ argument that only the appropriateness of the methodology in the abstract was subject of gatekeeping); Kumho Tire Co. v. Carmichael, 526 U.S. 137, 156-57 (1999) (“stressing that district courts must scrutinize whether the principles and methods employed by an expert have been properly applied to the facts of the case”) (quoting what was then the proposed advisory committee’s note to Rule 702, Preliminary Draft of Proposed Amendments to the Federal Rules of Civil Procedure and Evidence: Request for Comment, 181 F.R.D. 18, 148 (1998)).

[3] citing Stephen A. Saltzburg, Edwin J. Imwinkelried, & Daniel J. Capra, “Keeping the Reformist Spirit Alive in Evidence Law,” 149 U. Pa. L. Rev. 1277, 1289-90 (2001). The authors note that other circuits have embraced the Paoli “any steps” approach. Bernstein & Lasker at 28 at n. 152 (citing Paz v. Brush Engineered Materials, Inc., 555 F.3d 383, 387-91 (5th Cir. 2009); McClain v. Metabolife Int’l, Inc., 401 F.3d 1233, 1245 (11th Cir. 2005); Dodge v. Cotter Corp., 328 F.3d 1212, 1222 (10th Cir. 2003); Amorgianos v. Nat’l R.R. Passenger Corp., 303 F.3d 256, 267 (2d Cir. 2002) (quoting In re Paoli, 35 F.3d at 746).

[4] See, e.g., City of Pomona v. SQM N. Am. Corp., 750 F.3d 1036, 1047 (9th Cir. 2014) (rejecting the Paoli any step approach without careful analysis of the statute, the advisory committee note, or Supreme Court decisions); Manpower, Inc. v. Ins. Co. of Pa., 732 F.3d 796, 808 (7th Cir. 2013) (“[t]he reliability of data and assumptions used in applying a methodology is tested by the adversarial process and determined by the jury; the court’s role is generally limited to assessing the reliability of the methodology – the framework – of the expert’s analysis”); Bonner v. ISP Techs., Inc., 259 F.3d 924, 929 (8th Cir. 2001) (“the factual basis of an expert opinion goes to the credibility of the testimony, not the admissibility, and it is up to the opposing party to examine the factual basis for the opinion in cross-examination”).

[5] General Electric Co. v. Joiner, 522 U.S. 136, 146-47 (1997) (holding that district court had the “discretion to conclude that the studies upon which the experts relied were not sufficient, whether individually or in combination, to support their conclusions that Joiner’s exposure to PCB’s contributed to his cancer”). Other federal and state courts have followed Joiner. See Allen v. Pa. Eng’g Corp., 102 F.3d 194, 198 (5th Cir. 1996) (“We are also unpersuaded that the ‘weight of the evidence’ methodology these experts use is scientifically acceptable for demonstrating a medical link between Allen’s EtO exposure and brain cancer.”). For similar rejections of vague claims that weak evidence add up to more than the sum of its parts, see Hollander v. Sandoz Pharm. Corp., 289 F.3d 1193, 1216 n.21 (10th Cir. 2002); Magistrini v. One Hour Martinizing Dry Cleaning, 180 F. Supp. 2d 584, 608 (D.N.J. 2002); Caraker v. Sandoz Pharm. Corp., 188 F. Supp. 2d 1026, 1040 (S.D. Ill. 2001); Siharath v. Sandoz Pharm. Corp., 131 F. Supp. 2d 1347, 1371 (N.D. Ga. 2001), aff’d sub nom. Rider v. Sandoz Pharm. Corp., 295 F.3d 1194 (11th Cir. 2002); Merck & Co. v. Garza, 347 S.W.3d 256, 268 (Tex. 2011); Estate of George v. Vt. League of Cities & Towns, 993 A.2d 367, 379-80 (Vt. 2010).

[6] Milward v. Acuity Specialty Products Group, Inc., 639 F.3d 11, 17-18 (1st Cir. 2011) (reversing the exclusion of expert witnesses who embraced WOE). Milward has garnered some limited support in a few courts, as noted by Bernstein and Lasker; see In re Fosamax (Alendronate Sodium) Prods. Liab. Litig., Nos. 11-5304, 08-08, 2013 WL 1558690, at *4 (D.N.J. Apr. 10, 2013); Harris v. CSX Transp., Inc., 753 S.E.2d 275, 287-89, 301-02 (W. Va. 2013).

[7] “SKAPP A LOT” (April 30, 2010).

[8] “Milward Symposium Organized by Plaintiffs’ Counsel and Witnesses” (Feb. 13, 2013); [http://perma.cc/PW2V-X7TK].

Posted in Expert Witnesses, Rule 702, Scientific Evidence | Comments Off on On Amending Rule 702 of the Federal Rules of Evidence

Clinical Trials and Epidemiologic Studies Biased by False and Misleading Data From Research Participants

October 2nd, 2015

Many legal commentators erroneously refer to epidemiologic studies as “admitted” into evidence.[1] These expressions are sloppy, and unfortunate, because they obscure the tenuousness of study validity, and the many hearsay levels that are represented by an epidemiologic study. Rule 702 permits expert witness opinion that has an epistemic basis, and Rule 703 allows expert witnesses to rely upon otherwise inadmissible facts and data, as long as real experts in the field would reasonably rely upon such facts and data. Nothing in Rule 702 or 703 make an epidemiologic study itself admissible. And the general inadmissibility of the studies themselves is a good thing, given that they will be meaningless to the trier of fact without the endorsements, qualifications, and explanations of an expert witness, and given that many studies are inaccurate, invalid, and lack data integrity to boot.

Dr. Frank Woodside was kind enough to call my attention to an interesting editorial piece in the current issue of the New England Journal of Medicine, which reinforced the importance of recognizing that epidemiologic studies and clinical trials are inadmissible in themselves. The editorial, by scientists from the National Institute of Environmental Health Studies and the National Institute on Drug Abuse, calls out the problem of study participants who lie, falsify, fail to disclose, and exaggerate important aspects of their medical histories as well as their data. See David B. Resnik & David J. McCann, “Deception by Research Participants,” 373 New Engl. J. Med. 1192 (2015). The editorial is an important caveat for those who would glibly describe epidemiologic studies and clinical trials as “admissible.”

As a reminder of the autonomy of those who participate in clinical trials and studies, we now refer to individuals in a study as “participants,” and not “subjects.” Resnik and McCann remind us, however, that notwithstanding their importance, study participants can bias a study in important ways. Citing other recent papers,[2] the editorialists note that clinical trials offer financial incentives to participants, which may lead to exaggeration of symptoms to ensure enrollment, to failure to disclose exclusionary medical conditions and information, and to withholding of embarrassing or inculpatory information. Although fabrication or falsification of medical history and data by research participants is not research misconduct by the investigators, the participants’ misconduct can seriously bias and undermine the validity and integrity of a study.

Resnik and McCann’s concerns about the accuracy and truthfulness of clinical trial participant medical data and information can mushroom exponentially in the context of observational studies that involve high-stakes claims for compensation and vindication on medical causation issues. Here are a couple of high-stakes examples.

The Brinton Study in Silicone Gel Breast Implant Litigation

In the silicone gel breast implant litigation, claimants looked forward to a study by one of their champions, Dr. Louis Brinton, of the National Cancer Institute (NCI). Brinton had obtained intramural funding to conduct a study of women who had had silicone gel breast implants and their health outcomes. To their consternation, the defendants in that litigation learned of Dr. Brinton’s close ties with plaintiffs’ counsel, plaintiffs’ support groups, and other advocates. Further investigation, including Freedom of Information Act requests to the NCI led to some disturbing and startling revelations.

In October 1996, a leading epidemiologist wrote a “concerned citizen” letter to Dr. Joseph Fraumeni, who was then the director of Epidemiology and Genetics at the NCI. The correspondent wrote to call Dr. Fraumeni’s attention to severe bias problems in Dr. Brinton’s pending study of disease and symptom outcomes among women who had had silicone breast implants. Dr. Brinton had written to an Oregon attorney (Michael Williams) to enlist him to encourage his clients to participate in Brinton’s NCI study.   Dr. Brinton had also written to a Philadelphia attorney (Steven Sheller) to seek permission to link potential study subjects to the global settlement database of information on women participating in the settlement. Perhaps most egregiously, Dr. Brinton and others had prepared a study Question & Answer sheet, from the National Institutes of Health, which ended with a ringing solicitation of “The study provides an opportunity for women who may be suffering as a result of implants to be heard. Now is your chance to make a major contribution to women’s health by supporting this essential research.” Dr. Brinton apparently had not thought of appealing to women with implants who did not have health problems.

Dr. Brinton’s methodology doomed her study from the start. Without access to the background materials, such as the principal investigator’s correspondence file, or the recruitment documents used to solicit participation of ill women in the study, the scientific community, and the silicone litigation defendants would not have had the important insights into serious bias and flaws of Brinton’s study.

The Racette-Scruggs’ Study in Welding Fume Litigation

The welding fume litigation saw its version of a study corrupted by the participation of litigants and potential litigants. Richard (Dickie) Scruggs and colleagues funded some neurological researchers to travel to Alabama and Mississippi to “screen” plaintiffs and potential plaintiffs in litigation for over claims of neurological injury and disease from welding fume exposure. The plaintiffs’ lawyers rounded up the research subjects (a.k.a. clients and potential clients), talked to them before the medical evaluations, and administered the study questionnaires. Clearly the study subjects were aware of Scruggs’ “research” hypothesis. The plaintiffs’ lawyers then invited researchers who saw the welding tradesmen, using a novel videotaping methodology, to evaluate the workers for parkinsonism.

After their sojourn, at Scruggs’ expense to Alabama and Mississippi, the researchers wrote up their results, with little or no detail of the circumstances of how they had acquired their research “participants,” or those participants’ motives to give accurate or inaccurate medical and employment history information. See Brad A. Racette, S.D. Tabbal, D. Jennings, L. Good, J.S. Perlmutter, and Brad Evanoff, “Prevalence of parkinsonism and relationship to exposure in a large sample of Alabama welders,” 64 Neurology 230 (2005); Brad A. Racette, et al., “A rapid method for mass screening for parkinsonism,” 27 Neurotoxicology 357 (2006) (a largely duplicative report of the Alabama welders study).

Defense counsel directed subpoenas to both Dr. Racette and his institution, Washington University St. Louis, for the study protocol, underlying data, data codes, and statistical analyses.  After a long discovery fight, the MDL court largely enforced the subpoenas.  See, e.g., In re Welding Fume Prods. Liab. Litig., MDL 1535, 2005 WL 5417815 (N.D. Ohio Oct. 18, 2005) (upholding defendants’ subpoena for protocol, data, data codes, statistical analyses, and other things from Dr. Racette’s Alabama study on welding and parkinsonism). After the defense had the opportunity to obtain and analyze the underlying data in the Scruggs-Racette study, the welding plaintiffs largely retreated from their epidemiologic case. The Racette Alabama study faded into the background of the trials.

Both the Brinton and the Racette studies are painful reminders of the importance of assessing the motives of the study participants in observational epidemiologic studies, and the participants’ ability to undermine data integrity. If the financial motives identified by Resnik and McCann are sufficient to lead participants to give false information, or to fail to disclose correct information, we can only imagine how powerful are the motives created by the American tort litigation system among actual and potential claimants when they participate in epidemiologic studies. Resnik and McCann may be correct that fabrication or falsification of medical history and data by research participants is not research misconduct by the investigators themselves, but investigators who turn a blind eye to the knowledge, intent, and motives of their research participants may be conducting studies that are doomed from the outset.

[1] Michael D. Green, D. Michal Freedman, Leon Gordis, “Reference Guide on Epidemiology 549, 551,” in Reference Manual on Scientific Evidence (3d ed. 2011) ( “Epidemiologic studies have been well received by courts deciding cases involving toxic substances. *** Well-conducted studies are uniformly admitted.) (citing David L. Faigman et al. eds., 3 Modern Scientific Evidence: The Law and Science of Expert Testimony § 23.1, at 187 (2007–08)).

[2] Eric Devine, Megan Waters, Megan Putnam, et al., “Concealment and fabrication by experienced research subjects,” 20 Clin. Trials 935 (2013); Rebecca Dresser, “Subversive subjects: rule-breaking and deception in clinical trials,” 41 J. Law Med. Ethics 829 (2013).

Posted in Data Sharing, Rule 702, Scientific Evidence, Scientific Misconduct, Underlying Data | Comments Off on Clinical Trials and Epidemiologic Studies Biased by False and Misleading Data From Research Participants

The C-8 (Perfluorooctanoic Acid) Litigation Against DuPont, part 1

September 27th, 2015

The first plaintiff has begun her trial against E.I. Du Pont De Nemours & Company (DuPont), for alleged harm from environmental exposure to perfluorooctanoic acid or its salts (PFOA). Ms. Carla Bartlett is claiming that she developed kidney cancer as a result of drinking water allegedly contaminated with PFOA by DuPont. Nicole Hong, “Chemical-Discharge Case Against DuPont Goes to Trial: Outcome could affect thousands of claims filed by other U.S. residents,” Wall St. J. (Sept. 13, 2015). The case is pending before Chief Judge Edmund A. Sargus, Jr., in the Southern District of Ohio.

PFOA is not classified as a carcinogen in the Integrated Risk Information System (IRIS), of the U.S. Environmental Protection Agency (EPA). In 2005, the EPA Office of Pollution Prevention and Toxics submitted a “Draft Risk Assessment of the Potential Human Health Effects Associated With Exposure to Perfluorooctanoic Acid and Its Salts (PFOA),” which is available at the EPA’s website. The draft report, which is based upon some epidemiology and mostly animal toxicology studies, stated that there was “suggestive evidence of carcinogenicity, but not sufficient to assess human carcinogenic potential.”

In 2013, The Health Council of the Netherlands evaluated the PFOA cancer issue, and found the data unsupportive of a causal conclusions. The Health Council of the Netherlands, “Perfluorooctanoic acid and its salts: Evaluation of the carcinogenicity and genotoxicity” (2013) (“The Committee is of the opinion that the available data on perfluorooctanoic acid and its salts are insufficient to evaluate the carcinogenic properties (category 3)”).

Last year, the World Health Organization (WHO) through its International Agency for Research on Cancer (IARC) reviewed the evidence on the alleged carcinogenicity of PFOA. The IARC, which has fostered much inflation with respect to carcinogenicity evaluations, classified as PFOA as only possibly carcinogenic. See News, “Carcinogenicity of perfluorooctanoic acid, tetrafl uoroethylene, dichloromethane, 1,2-dichloropropane, and 1,3-propane sultone,” 15 The Lancet Oncology 924 (2014).

Most independent reviews also find the animal and epidemiologic unsupportive of a causal conclusion between PFOA and any human cancer. See, e.g., Thorsten Stahl, Daniela Mattern, and Hubertus Brunn, “Toxicology of perfluorinated compounds,” 23 Environmental Sciences Europe 38 (2011).

So you might wonder how DuPont lost its Rule 702 challenges in such a case, which it surely did. In re E. I. du Pont de Nemours & Co. C-8 Pers. Injury Litig., Civil Action 2:13-md-2433, 2015 U.S. Dist. LEXIS 98788 (S.D. Ohio July 21, 2015). That is a story for another day.

Posted in Causation, Expert Witnesses, Rule 702, Scientific Evidence, Uncategorized | Comments Off on The C-8 (Perfluorooctanoic Acid) Litigation Against DuPont, part 1

David Faigman’s Critique of G2i Inferences at Weinstein Symposium

September 25th, 2015

The DePaul Law Review’s 20th Annual Clifford Symposium on Tort Law and Social Policy is an 800-plus page tribute in honor of Judge Jack Weinstein. 64 DePaul L. Rev. (Winter 2015). There are many notable, thought-provoking articles, but my attention was commanded by the contribution on Judge Weinstein’s approach to expert witness opinion evidence. David L. Faigman & Claire Lesikar, “Organized Common Sense: Some Lessons from Judge Jack Weinstein’s Uncommonly Sensible Approach to Expert Evidence,” 64 DePaul L. Rev. 421 (2015) [cited as Faigman].

Professor Faigman praises Judge Jack Weinstein for his substantial contributions to expert witness jurisprudence, while acknowledging that Judge Weinstein has been a sometimes reluctant participant and supporter of judicial gatekeeping of expert witness testimony. Professor Faigman also uses the occasion to restate his own views about the so-called “G2i” problem, the problem of translating general knowledge that pertains to groups to individual cases. In the law of torts, the G2i problem arises from the law’s requirement that plaintiffs show that they were harmed by defendants’ products or environmental exposures. In the context of modern biological “sufficient” causal set principles, this “proof” requirement entails that the product or exposure can cause the specified harms in human beings generally (“general causation”) and that the product or exposure actually played a causal role in bringing about plaintiffs’ specific harms.

Faigman makes the helpful point that courts initially and incorrectly invoked “differential diagnosis,” as the generally accepted methodology for attributing causation. In doing so, the courts extrapolated from the general acceptance of differential diagnosis in the medical community to the courtroom testimony about etiology. The extrapolation often glossed over the methodological weaknesses of the differential approach to etiology. Not until 1995 did a court wake to the realization that what was being proffered was a “differential etiology,” and not a differential diagnosis. McCullock v. H.B. Fuller Co., 61 F.3d 1038, 1043 (2d Cir. 1995). This realization, however, did not necessarily stimulate the courts’ analytical faculties, and for the most part, they treated the methodology of specific causal attribution as general acceptance and uncontroversial. Faigman’s point that the courts need to pay attention to the methodological challenges to differential etiological analysis is well taken.

Faigman also claims, however, that in advancing “differential etiologies, expert witnesses were inventing wholesale an approach that had no foundation or acceptance in their scientific disciplines:

 “Differential etiology is ostensibly a scientific methodology, but one not developed by, or even recognized by, physicians or scientists. As described, it is entirely logical, but has no scientific methods or principles underlying it. It is a legal invention and, as such, has analytical heft, but it is entirely bereft of empirical grounding. Courts and commentators have so far merely described the logic of differential etiology; they have yet to define what that methodology is.”

Faigman at 444.[1] Faigman is correct that courts often have left unarticulated exactly what the methodology is, but he does not quite make sense when he writes that the method of differential etiology is “entirely logical,” but has no “scientific methods or principles underlying it.” Afterall, Faigman starts off his essay with a quotation from Thomas Huxley that “science is nothing but trained and organized common sense.”[2] As I have written elsewhere, the form of reasoning involved in differential diagnosis is nothing other than the iterative disjunctive syllogism.[3] Either-or reasoning occurs throughout the physical and biological sciences; it is not clear why Faigman declares it un- or extra-scientific.

The strength of Faigman’s claim about the made-up nature of differential etiology appears to be undermined and contradicted by an example that he provides from clinical allergy and immunology:

“Allergists, for example, attempt to identify the etiology of allergic reactions in order to treat them (or to advise the patient to avoid what caused them), though it might still be possible to treat the allergic reactions without knowing their etiology.”

Faigman at 437. Of course, not only allergists try to determine the cause of an individual patient’s disease. Psychiatrists, in the psychoanalytic tradition, certain do so as well. Physicians who use predictive regression models use group data, in multivariate analyses, to predict outcomes, risk, and mortality in individual patients. Faigman’s claim is similarly undermined by the existence of a few diseases (other than infectious diseases) that are defined by the causative exposure. Silicosis and manganism have played a large role in often bogus litigation, but they represent instances in which a differential diagnosis and puzzle may also be an etiological diagnosis and puzzle. Of course, to the extent that a disease is defined in terms of causative exposures, there may be serious and even intractable problems caused by the lack of specificity and accuracy in the diagnostic criteria for the supposedly pathognomonic disease.

As for whether the concept of “differential etiology” is ever used in the sciences themselves, a few citations for consideration follow.

Kløve & D. Doehring, “MMPI in epileptic groups with differential etiology,” 18 J. Clin. Psychol. 149 (1962)

Kløve & C. Matthews, “Psychometric and adaptive abilities in epilepsy with differential etiology,” 7 Epilepsia 330 (1966)

Teuber & K. Usadel, “Immunosuppression in juvenile diabetes mellitus? Critical viewpoint on the treatment with cyclosporin A with consideration of the differential etiology,” 103 Fortschr. Med. 707 (1985)

G.May & W. May, “Detection of serum IgA antibodies to varicella zoster virus (VZV)–differential etiology of peripheral facial paralysis. A case report,” 74 Laryngorhinootologie 553 (1995)

Alan Roberts, “Psychiatric Comorbidity in White and African-American Illicity Substance Abusers” Evidence for Differential Etiology,” 20 Clinical Psych. Rev. 667 (2000)

Mark E. Mullinsa, Michael H. Leva, Dawid Schellingerhout, Gilberto Gonzalez, and Pamela W. Schaefera, “Intracranial Hemorrhage Complicating Acute Stroke: How Common Is Hemorrhagic Stroke on Initial Head CT Scan and How Often Is Initial Clinical Diagnosis of Acute Stroke Eventually Confirmed?” 26 Am. J. Neuroradiology 2207 (2005)

Qiang Fua, et al., “Differential Etiology of Posttraumatic Stress Disorder with Conduct Disorder and Major Depression in Male Veterans,” 62 Biological Psychiatry 1088 (2007)

Jesse L. Hawke, et al., “Etiology of reading difficulties as a function of gender and severity,” 20 Reading and Writing 13 (2007)

Mastrangelo, “A rare occupation causing mesothelioma: mechanisms and differential etiology,” 105 Med. Lav. 337 (2014)

[1] See also Faigman at 448 (“courts have invented a methodology – differential etiology – that purports to resolve the G2i problem. Unfortunately, this method has only so far been described; it has not been defined with any precision. For now, it remains a highly ambiguous idea, sound in principle, but profoundly underdefined.”).

[2] Thomas H. Huxley, “On the Education Value of the Natural History Sciences” (1854), in Lay Sermons, Addresses and Reviews 77 (1915).

[3] See, e.g., “Differential Etiology and Other Courtroom Magic” (June 23, 2014) (collecting cases); “Differential Diagnosis in Milward v. Acuity Specialty Products Group” (Sept. 26, 2013).

Posted in Causation, Expert Witnesses, Rule 702, Scientific Evidence | Comments Off on David Faigman’s Critique of G2i Inferences at Weinstein Symposium

Beecher-Monas Proposes to Abandon Common Sense, Science, and Expert Witnesses for Specific Causation

September 11th, 2015

Law reviews are not peer reviewed, not that peer review is a strong guarantor of credibility, accuracy, and truth. Most law reviews have no regular provision for letters to the editor; nor is there a PubPeer that permits readers to point out errors for the benefit of the legal community. Nonetheless, law review articles are cited by lawyers and judges, often at face value, for claims and statements made by article authors. Law review articles are thus a potent source of misleading, erroneous, and mischievous ideas and claims.

Erica Beecher-Monas is a law professor at Wayne State University Law School, or Wayne Law, which considers itself “the premier public-interest law school in the Midwest.” Beware of anyone or any institution that describes itself as working for the public interest. That claim alone should put us on our guard against whose interests are being included and excluded as legitimate “public” interest.

Back in 2006, Professor Beecher-Monas published a book on evaluating scientific evidence in court, which had a few goods points in a sea of error and nonsense. See Erica Beecher-Monas, Evaluating Scientific Evidence: An Interdisciplinary Framework for Intellectual Due Process (2006)[1]. More recently, Beecher-Monas has published a law review article, which from its abstract suggests that she might have something to say about this difficult area of the law:

“Scientists and jurists may appear to speak the same language, but they often mean very different things. The use of statistics is basic to scientific endeavors. But judges frequently misunderstand the terminology and reasoning of the statistics used in scientific testimony. The way scientists understand causal inference in their writings and practice, for example, differs radically from the testimony jurists require to prove causation in court. The result is a disconnect between science as it is practiced and understood by scientists, and its legal use in the courtroom. Nowhere is this more evident than in the language of statistical reasoning.

Unacknowledged difficulties in reasoning from group data to the individual case (in civil cases) and the absence of group data in making assertions about the individual (in criminal cases) beset the courts. Although nominally speaking the same language, scientists and jurists often appear to be in dire need of translators. Since expert testimony has become a mainstay of both civil and criminal litigation, this failure to communicate creates a conundrum in which jurists insist on testimony that experts are not capable of giving, and scientists attempt to conform their testimony to what the courts demand, often well beyond the limits of their expertise.”

Beecher-Monas, “Lost in Translation: Statistical Inference in Court,” 46 Arizona St. L.J. 1057, 1057 (2014) [cited as BM].

A close read of the article shows, however, that Beecher-Monas continues to promulgate misunderstanding, error, and misdirection on statistical and scientific evidence.

Individual or Specific Causation

The key thesis of this law review is that expert witnesses have no scientific or epistemic warrant upon which to opine about individual or specific causation.

“But what statistics cannot do—nor can the fields employing statistics, like epidemiology and toxicology, and DNA identification, to name a few—is to ascribe individual causation.”

BM at 1057-58.

Beecher-Monas tells us that expert witnesses are quite willing to opine on specific causation, but that they have no scientific or statistical warrant for doing so:

“Statistics is the law of large numbers. It can tell us much about populations. It can tell us, for example, that so-and-so is a member of a group that has a particular chance of developing cancer. It can tell us that exposure to a chemical or drug increases the risk to that group by a certain percentage. What statistics cannot do is tell which exposed person with cancer developed it because of exposure. This creates a conundrum for the courts, because nearly always the legal question is about the individual rather than the group to which the individual belongs.”

BM at 1057. Clinical medicine and science come in for particular chastisement by Beecher-Monas, who acknowledges the medical profession’s legitimate role in diagnosing and treating disease. Physicians use a process of differential diagnosis to arrive at the most likely diagnosis of disease, but the etiology of the disease is not part of their normal practice. Beecher-Monas leaps beyond the generalization that physicians infrequently ascertain specific causation to the sweeping claim that ascertaining the cause of a patient’s disease is beyond the clinician’s competence and scientific justification. Beecher-Monas thus tells us, in apodictic terms, that science has nothing to say about individual or specific causation. BM at 1064, 1075.

In a variety of contexts, but especially in the toxic tort arena, expert witness testimony is not reliable with respect to the inference of specific causation, which, Beecher-Monas writes, usually without qualification, is “unsupported by science.” BM at 1061. The solution for Beecher-Monas is clear. Admitting baseless expert witness testimony is “pernicious” because the whole purpose of having expert witnesses is to help the fact finder, jury or judge, who lack the background understanding and knowledge to assess the data, interpret all the evidence, and evaluate the epistemic warrant for the claims in the case. BM at 1061-62. Beecher-Monas would thus allow the expert witnesses to testify about what they legitimately know, and let the jury draw the inference about which expert witnesses in the field cannot and should not opine. BM at 1101. In other words, Beecher-Monas is perfectly fine with juries and judges guessing their way to a verdict on an issue that science cannot answer. If her book danced around this recommendation, now her law review article has come out into the open, declaring an open season to permit juries and judges to be unfettered in their specific causation judgments. What is touching is that Beecher-Monas is sufficiently committed to gatekeeping of expert witness opinion testimony that she proposes a solution to take a complex area away from expert witnesses altogether rather than confront the reality that there is often simply no good way to connect general and specific causation in a given person.

Causal Pies

Beecher-Monas relies heavily upon Professor Rothman’s notion of causal pies or sets to describe the factors that may combine to bring about a particular outcome. In doing so, she commits a non-sequitur:

“Indeed, epidemiologists speak in terms of causal pies rather than a single cause. It is simply not possible to infer logically whether a specific factor caused a particular illness.”[2]

BM at 1063. But the question on her adopted model of causation is not whether any specific factor was the cause, but whether it was one of the multiple slices in the pie. Her citation to Rothman’s statement that “it is not possible to infer logically whether a specific factor was the cause of an observed event,” is not the problem that faces factfinders in court cases.

With respect to differential etiology, Beecher-Monas claims that “‘ruling in’ all potential causes cannot be done.” BM at 1075. But why not? While it is true that disease diagnosis is often made upon signs and symptoms, BM at 1076, sometimes physicians are involved in trying to identify causes in individuals. Psychiatrists of course are frequently involved in trying to identify sources of anxiety and depression in their patients. It is not all about putting a DSM-V diagnosis on the chart, and prescribing medication. And there are times, when physicians can say quite confidently that a disease has a particular genetic cause, as in a man with BrCa1, or BrCa2, and breast cancer, or certain forms of neurodegenerative diseases, or an infant with a clearly genetically determined birth defect.

Beecher-Monas confuses “the” cause with “a” cause, and wonders away from both law and science into her own twilight zone. Here is an example of how Beecher-Monas’ confusion plays out. She asserts that:

“For any individual case of lung cancer, however, smoking is no more important than any of the other component causes, some of which may be unknown.”

BM at 1078. This ignores the magnitude of the risk factor and its likely contribution to a given case. Putting aside synergistic co-exposures, for most lung cancers, smoking is the “but for” cause of individual smokers’ lung cancers. Beecher-Monas sets up a strawman argument by telling us that is logically impossible to infer “whether a specific factor in a causal pie was the cause of an observed event.” BM at 1079. But we are usually interested in whether a specific factor was “a substantial contributing factor,” without which the disease would not have occurred. This is hardly illogical or impracticable for a given case of mesothelioma in a patient who worked for years in a crocidolite asbestos factor, or for a case of lung cancer in a patient who smoked heavily for many years right up to the time of his lung cancer diagnosis. I doubt that many people would hesitate, on either logical or scientific grounds, to attribute a child’s phocomelia birth defects to his mother’s ingestion of thalidomide during an appropriate gestational window in her pregnancy.

Unhelpfully, Beecher-Monas insists upon playing this word game by telling us that:

“Looking backward from an individual case of lung cancer, in a person exposed to both asbestos and smoking, to try to determine the cause, we cannot separate which factor was primarily responsible.”

BM at 1080. And yet that issue, of “primary responsibility” is not in any jury instruction for causation in any state of the Union, to my knowledge.

From her extreme skepticism, Beecher-Monas swings to the other extreme that asserts that anything that could have been in the causal set or pie was in the causal set:

“Nothing in relative risk analysis, in statistical analysis, nor anything in medical training, permits an inference of specific causation in the individual case. No expert can tell whether a particular exposed individual’s cancer was caused by unknown factors (was idiopathic), linked to a particular gene, or caused by the individual’s chemical exposure. If all three are present, and general causation has been established for the chemical exposure, one can only infer that they all caused the disease.115 Courts demanding that experts make a contrary inference, that one of the factors was the primary cause, are asking to be misled. Experts who have tried to point that out, however, have had a difficult time getting their testimony admitted.”

BM at 1080. There is no support for Beecher-Monas’ extreme statement. She cites, in footnote 115, to Kenneth Rothman’s introductory book on epidemiology, but what he says at the cited page is quite different. Rothman explains that “every component cause that played a role was necessary to the occurrence of that case.” In other words, for every component cause that actually participated in bringing about this case, its presence was necessary to the occurrence of the case. What Rothman clearly does not say is that for a given individual’s case, the fact that a factor can cause a person’s disease means that it must have caused it. In Beecher-Monas’ hypothetical of three factors – idiopathic, particular gene, and chemical exposure, all three, or any two, or only one of the three may have made a given individual’s causal set. Beecher-Monas has carelessly or intentionally misrepresented Rothman’s actual discussion.

Physicians and epidemiologists do apply group risk figures to individuals, through the lens of predictive regression equations.   The Gail Model for 5 Year Risk of Breast Cancer, for instance, is a predictive equation that comes up with a prediction for an individual patient by refining the subgroup within which the patient fits. Similarly, there are prediction models for heart attack, such as the Risk Assessment Tool for Estimating Your 10-year Risk of Having a Heart Attack. Beecher-Monas might complain that these regression equations still turn on subgroup average risk, but the point is that they can be made increasingly precise as knowledge accumulates. And the regression equations can generate confidence intervals and prediction intervals for the individual’s constellation of risk factors.

Significance Probability and Statistical Significance

The discussion of significance probability and significance testing in Beecher-Monas’ book was frequently in error,[3] and this new law review article is not much improved. Beecher-Monas tells us that “judges frequently misunderstand the terminology and reasoning of the statistics used in scientific testimony,” BM at 1057, which is true enough, but this article does little to ameliorate the situation. Beecher-Monas offers the following definition of the p-value:

“The P- value is the probability, assuming the null hypothesis (of no effect) is true (and the study is free of bias) of observing as strong an association as was observed.”

BM at 1064-65. This definition misses that the p-value is a cumulative tail probability, and can be one-sided or two-sided. More seriously in error, however, is the suggestion that the null hypothesis is one of no effect, when it is merely a pre-specified expected value that is the subject of the test. Of course, the null hypothesis is often one of no disparity between the observed and the expected, but the definition should not mislead on this crucial point.

For some reason, Beecher-Monas persists in describing the conventional level of statistical significance as 95%, which substitutes the coefficient of confidence for the complement of the frequently pre-specified p-value for significance. Annoying but decipherable. See, e.g., BM at 1062, 1064, 1065. She misleadingly states that:

“The investigator will thus choose the significance level based on the size of the study, the size of the effect, and the trade-off between Type I (incorrect rejection of the null hypothesis) and Type II (incorrect failure to reject the null hypothesis) errors.”

BM at 1066. While this statement is sometimes, rarely true, it mostly is not. A quick review of the last several years of the New England Journal of Medicine will document the error. Invariably, researchers use the conventional level of alpha, at 5%, unless there is multiple testing, such as in a genetic association study.

Beecher-Monas admonishes us that “[u]sing statistical significance as a screening device is thus mistaken on many levels,” citing cases that do not provide support for this proposition.[4] BM at 1066. The Food and Drug Administration’s scientists, who review clinical trials for efficacy and safety will be no doubt be astonished to hear this admonition.

Beecher-Monas argues that courts should not factor statistical significance or confidence intervals into their gatekeeping of expert witnesses, but that they should “admit studies,” and leave it to the lawyers and expert witnesses to explain the strengths and weaknesses of the studies relied upon. BM at 1071. Of course, studies themselves are rarely admitted because they represent many levels of hearsay by unknown declarants. Given Beecher-Monas’ acknowledgment of how poorly judges and lawyers understand statistical significance, this argument is cynical indeed.

Remarkably, Beecher-Monas declares, without citation, that the

“the purpose of epidemiologists’ use of statistical concepts like relative risk, confidence intervals, and statistical significance are intended to describe studies, not to weed out the invalid from the valid.”

BM at 1095. She thus excludes by ipse dixit any inferential purposes these statistical tools have. She goes further and gives us a concrete example:

“If the methodology is otherwise sound, small studies that fail to meet a P-level of 5 [sic], say, or have a relative risk of 1.3 for example, or a confidence level that includes 1 at 95% confidence, but relative risk greater than 1 at 90% confidence ought to be admissible. And understanding that statistics in context means that data from many sources need to be considered in the causation assessment means courts should not dismiss non-epidemiological evidence out of hand.”

BM at 1095. Well, again, studies are not admissible; the issue is whether they may be reasonably relied upon, and whether reliance upon them may support an opinion claiming causality. And a “P-level” of 5 is, well, let us hope a serious typographical error. Beecher-Monas’ advice is especially misleading when there is there is only one study, or only one study in a constellation of exonerative studies. See, e.g., In re Accutane, No. 271(MCL), 2015 WL 753674, 2015 BL 59277 (N.J. Super. Law Div. Atlantic Cty. Feb. 20, 2015) (excluding Professor David Madigan for cherry picking studies to rely upon).

Confidence Intervals

Beecher-Monas’ book provided a good deal of erroneous information on confidence intervals.[5] The current article improves on the definitions, but still manages to go astray:

“The rationale courts often give for the categorical exclusion of studies with confidence intervals including the relative risk of one is that such studies lack statistical significance.62 Well, yes and no. The problem here is the courts’ use of a dichotomous meaning for statistical significance (significant or not).63 This is not a correct understanding of statistical significance.”

BM at 1069. Well yes and no; this interpretation of a confidence interval, say with a coefficient of confidence of 95%, is a reasonable interpretation of whether the point estimate is statistically significant at an alpa of 5%. If Beecher-Monas does not like strict significant testing, that is fine, but she cannot mandate its abandonment by scientists or the courts. Certainly the cited interpretation is one proper interpretation among several.

Power

There were several misleading references to statistical power in Beecher-Monas’ book, but the new law review tops them by giving a new, bogus definition:

“Power, the probability that the study in which the hypothesis is being tested will reject the alterative [sic] hypothesis when it is false, increases with the size of the study.”

BM at 1065. For this definition, Beecher-Monas cites to the Reference Manual on Scientific Evidence, but butchers the correct definition give by the late David Freedman and David Kaye.[6] All of which is very disturbing.

Relative Risks and Other Risk Measures

Beecher-Monas begins badly by misdefining the concept of relative risk:

“as the percentage of risk in the exposed population attributable to the agent under investigation.”

BM at 1068. Perhaps this percentage can be derived from the relative risk, if we know it to be the true measure with some certainty, through a calculation of attributable risk, but confusing and conflating attributable and relative risk in a law review article that is taking the entire medical profession to task, and most of the judiciary to boot, should be written more carefully.

Then Beecher-Monas tells us that the “[r]elative risk is a statistical test that (like statistical significance) depends on the size of the population being tested.” BM at 1068. Well, actually not; the calculation of the RR is unaffected by the sample size. The variance of course will vary with the sample size, but Beecher-Monas seems intent on ignoring random variability.

Perhaps most egregious is Beecher-Monas’ assertion that:

“Any increase above a relative risk of one indicates that there is some effect.”

BM at 1067. So much for ruling out chance, bias, and confounding! Or looking at an entire body of epidemiologic research for strength, consistency, coherence, exposure-response, etc. Beecher-Monas has thus moved beyond a liberal, to a libertine, position. In case the reader has any doubts of the idiosyncrasy of her views, she repeats herself:

“As long as there is a relative risk greater than 1.0, there is some association, and experts should be permitted to base their causal explanations on such studies.”

BM at 1067-68. This is evidentiary nihilism in full glory. Beecher-Monas has endorsed relying upon studies irrespective of their study design or validity, their individual confidence intervals, their aggregate summary point estimates and confidence intervals, or the absence of important Bradford Hill considerations, such as consistency, strength, and dose-response. So an expert witness may opine about general causation from reliance upon a single study with a relative risk of 1.05, say with a 95% confidence interval of 0.8 – 1.4?[7] For this startling proposition, Beecher-Monas cites the work of Sander Greenland, a wild and wooly plaintiffs’ expert witness in various toxic tort litigations, including vaccine autism and silicone autoimmune cases.

RR > 2

Beecher-Monas’ discussion of inferring specific causation from relative risks greater than two devolves into a muddle by her failure to distinguish general from specific causation. BM at 1067. There are different relevancies for general and specific causation, depending upon context, such as clinical trials or epidemiologic studies for general causation, number of studies available, and the like. Ultimately, she adds little to the discussion and debate about this issue, or any other.

[1] See previous comments on the book at “Beecher-Monas and the Attempt to Eviscerate Daubert from Within”; “Friendly Fire Takes Aim at Daubert – Beecher-Monas And The Undue Attack on Expert Witness Gatekeeping; and “Confidence in Intervals and Diffidence in the Courts.”

[2] Kenneth J. Rothman, Epidemiology: An Introduction 250 (2d ed. 2012).

[3] Erica Beecher-Monas, Evaluating Scientific Evidence: An Interdisciplinary Framework for Intellectual Due Process 42 n. 30, 61 (2007) (“Another way of explaining this is that it describes the probability that the procedure produced the observed effect by chance.”) (“Statistical significance is a statement about the frequency with which a particular finding is likely to arise by chance.”).

[4] See BM at 1066 & n. 44, citing “See, e.g., In re Breast Implant Litig., 11 F. Supp. 2d 1217, 1226–27 (D. Colo. 1998); Haggerty v. Upjohn Co., 950 F. Supp. 1160, 1164 (S.D. Fla. 1996), aff’d, 158 F.3d 588 (11th Cir. 1998) (“[S]cientifically valid cause and effect determinations depend on controlled clinical trials and epidemiological studies.”).”

 

[5] See, e.g., Erica Beecher-Monas, Evaluating Scientific Evidence 58, 67 (N.Y. 2007) (“No matter how persuasive epidemiological or toxicological studies may be, they could not show individual causation, although they might enable a (probabilistic) judgment about the association of a particular chemical exposure to human disease in general.”) (“While significance testing characterizes the probability that the relative risk would be the same as found in the study as if the results were due to chance, a relative risk of 2 is the threshold for a greater than 50 percent chance that the effect was caused by the agent in question.”)(incorrectly describing significance probability as a point probability as opposed to tail probabilities).

[6] David H. Kaye & David A. Freedman, Reference Guide on Statistics, in Federal Jud. Ctr., Reference Manual on Scientific Evidence 211, 253–54 (3d ed. 2011) (discussing the statistical concept of power).

[7] BM at 1070 (pointing to a passage in the FJC’s Reference Manual on Scientific Evidence that provides an example of one 95% confidence interval that includes 1.0, but which shrinks when calculated as a 90% interval to 1.1 to 2.2, which values “demonstrate some effect with confidence interval set at 90%). This is nonsense in the context of observational studies.

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Seventh Circuit Affirms Exclusion of Expert Witnesses in Vinyl Chloride Case

August 30th, 2015

Last week, the Seventh Circuit affirmed a federal district court’s exclusion of plaintiffs’ expert witnesses in an environmental vinyl chloride exposure case. Wood v. Textron, Inc., No. 3:10 CV 87, 2014 U.S. Dist. LEXIS 34938 (N.D. Ind. Mar. 17, 2014); 2014 U.S. Dist. LEXIS 141593, at *11 (N.D. Ind. Oct. 3, 2014), aff’d, Slip op., No. 14-3448, 20125 U.S. App. LEXIS 15076 (7th Cir. Aug. 26, 2015). Plaintiffs, children C.W. and E.W., claimed exposure from Textron’s manufacturing facility in Rochester, Indiana, which released vinyl chloride as a gas that seeped into ground water, and into neighborhood residential water wells. Slip op. at 2-3. Plaintiffs claimed present injuries in the form of “gastrointestinal issues (vomiting, bloody stools), immunological issues, and neurological issues,” as well as future increased risk of cancer. Importantly, the appellate court explicitly approved the trial court’s careful reading of relied upon studies to determine whether they really did support the scientific causal claims made by the expert witnesses. Given the reluctance of some federal district judges to engage with the studies actually cited, this holding is noteworthy.

To support their claims, plaintiffs offered the testimony from three familiar expert witnesses:

(1) Dr. James G. Dahlgren;

(2) Dr. Vera S. Byers; and

(3) Dr. Jill E. Ryer-Powder.

Slip op. at 5. This gaggle offered well-rehearsed but scientifically unsound arguments in place of actual evidence that the children were hurt, or would be afflicted, as a result of their claimed exposures:

(a) extrapolation from high dose animal and human studies;

(b) assertions of children’s heightened vulnerability;

(c) differential etiology;

(d) temporality; and

(e) regulatory exposure limits.

On appeal, a panel of the Seventh Circuit held that the district court had properly conducted “an in-depth review of the relevant studies that the experts relied upon to generate their differential etiology,” and their general causation opinions. Slip op. at 13-14 (distinguishing other Seventh Circuit decisions that reversed district court Rule 702 rulings, and noting that the court below followed Joiner’s lead by analyzing the relied-upon studies to assess analytical gaps and extrapolations). The plaintiffs’ expert witnesses simply failed in analytical gap bridging, and dot connecting.

Extrapolation

The Circuit agreed with the district court that the extrapolations asserted were extreme, and that they represented “analytical gaps” too wide to be permitted in a courtroom. Slip op. at 15. The challenged expert witnesses extrapolated between species, between exposure levels, between exposure duration, between exposure circumstances, and between disease outcomes.

The district court faulted Dahlgren for relying upon articles that “fail to establish that [vinyl chloride] at the dose and duration present in this case could cause the problems that the [p]laintiffs have experienced or claim that they are likely to experience.” C.W. v. Textron, 2014 U.S. Dist. LEXIS 34938, at *53, *45 (N.D. Ind. Mar. 17, 2014) (finding that the analytical gap between the cited studies and Dahlgren’s purpose in citing the studies was an unbridged gap, which Dahlgren had failed to explain). Slip op. at 8.

Byers, for instance, cited one study[1] that involved exposure for five years, at an average level that was over 1,000 times higher than the children’s alleged exposure levels, which lasted less than 17 and 7 months, each. Perhaps even more extreme were the plaintiffs’ expert witnesses’ attempted extrapolations from animal studies, which the district court recognized as “too attenuated” from plaintiffs’ case. Slip op. at 14. The Seventh Circuit rejected plaintiffs’ alleged error that the district court had imposed a requirement of “absolute precision,” in holding that the plaintiffs’ expert witnesses’ analytical gaps (and slips) were too wide to be bridged. The Circuit provided a colorful example of a study on laboratory rodents, pressed into service for a long-term carcinogenetic assay, which found no statistically significant increase in tumors fed 0.03 milligrams vinyl chloride per kilogram of bodyweight, (0.03 mg/kg), for 4 to 5 days each week, for 59 weeks, compared to control rodents fed olive oil.[2] Slip op. at 14-15. This exposure level in this study of 0.03 mg/kg was over 10 times the children’s exposure, as estimated by Ryer-Powder. The 59 weeks of study exposure represents the great majority of the rodents’ adult years, which greatly exceeds the children’s exposure was took place over several months of their lives. Slip op. at 15.

The Circuit held that the district court was within its discretion in evaluating the analytical gaps, and that the district court was correct to look at the study details to exercise its role as a gatekeeper under Rule 702. Slip op. at 15-17. The plaintiffs’ expert witnesses failed to explain their extrapolations, which was made their opinions suspect. As the Circuit court noted, there is a methodology by which scientists sometimes attempt to model human risks from animal evidence. Slip op. at 16-17, citing Bernard D. Goldtsein & Mary Sue Henifin, “Reference Guide on Toxicology,” in Federal Manual on Scientific Evidence 646 (3d ed. 2011) (“The mathematical depiction of the process by which an external dose moves through various compartments in the body until it reaches the target organ is often called physiologically based pharmokinetics or toxicokinetics.”). Given the abject failures of plaintiffs’ expert witnesses to explain their leaps of faith, the appellate court had no occasion to explore the limits of risk assessment outside regulatory contexts.

Children’s Vulnerability

Plaintiffs’ expert witness asserted that children are much more susceptible than adult workers, and even laboratory rats. As is typical in such cases, these expert witnesses had no evidence to support their assertions, and they made no effort even to invoke models that attempted reasonable risk assessments of children’s risk.

Differential Etiology

Dahlgren and Byers both claimed that they reached individual or specific causation conclusions based upon their conduct of a “differential etiology.” The trial and appellate court both faulted them for failing to “rule in” vinyl chloride for plaintiffs’ specific ailments before going about the business of ruling out competing or alternative causes. Slip op. at 6-7; 9-10; 20-21.

The courts also rejected Dahlgren’s claim that he could rule out all potential alternative causes by noting that the children’s treating physicians had failed to identify any cause for their ailments. So after postulating a limited universe of alternative causes of “inheritance, allergy, infection or another poison,” Dahlgren ruled all of them out of the case, because these putative causes “would have been detected by [the appellants’] doctors and treated accordingly.” Slip op. at 7, 18. As the Circuit court saw the matter:

“[T]his approach is not the stuff of science. It is based on faith in his fellow physicians—nothing more. The district court did not abuse its discretion in rejecting it.”

Slip op. at 18. Of course, the court might well have noted that physicians are often concerned exclusively with identifying effective therapy, and have little or nothing to offer on actual causation.

The Seventh Circuit panel did fuss with dicta in the trial court’s opinion that suggested differential etiology “cannot be used to support general causation.” C.W. v. Textron, 2014 U.S. Dist. LEXIS 141593, at *11 (N.D. Ind. Oct. 3, 2014). Elsewhere, the trial court wrote, in a footnote, that “[d]ifferential [etiology] is admissible only insofar as it supports specific causation, which is secondary to general causation … .” Id. at *12 n.3. Curiously the appellate court characterized these statements as “holdings” of the trial court, but disproved their own characterization by affirming the judgment below. The Circuit court countered with its own dicta that

“there may be a case where a rigorous differential etiology is sufficient to help prove, if not prove altogether, both general and specific causation.”

Slip op. at 20 (citing, in turn, improvident dicta from the Second Circuit, in Ruggiero v. Warner-Lambert Co., 424 F.3d 249, 254 (2d Cir. 2005) (“There may be instances where, because of the rigor of differential diagnosis performed, the expert’s training and experience, the type of illness or injury at issue, or some other … circumstance, a differential diagnosis is sufficient to support an expert’s opinion in support of both general and specific causation.”).

Regulatory Pronouncements

Dahlgren based his opinions upon the children’s water supply containing vinyl chloride in excess of regulatory levels set by state and federal agencies, including the U.S. Environmental Protection Agency (E.P.A.). Slip op. at 6. Similarly, Ryer-Powder relied upon exposure levels’ exceeding regulatory permissible limits for her causation opinions. Slip op. at 10.

The district court, with the approval now of the Seventh Circuit would have none of this nonsense. Exceeding governmental regulatory exposure limits does not prove causation. The con-compliance does not help the fact finder without knowing “the specific dangers” that led the agency to set the permissible level, and thus the regulations are not relevant at all without this information. Even with respect to specific causation, the regulatory infraction may be weak or null evidence for causation. Slip op. at 18-19 (citing Cunningham v. Masterwear Corp., 569 F.3d 673, 674–75 (7th Cir. 2009).

Temporality

Byers and Dahlgren also emphasized that the children’s symptoms began after exposure and abated after removal from exposure. Slip op. at 9, 6-7. Both the trial and appellate courts were duly unimpressed by the post hoc ergo propter hoc argument. Slip op. at 19, citing Ervin v. Johnson & Johnson, 492 F.3d 901, 904-05 (7th Cir. 2007) (“The mere existence of a temporal relationship between taking a medication and the onset of symptoms does not show a sufficient causal relationship.”).

Increased Risk of Cancer

The plaintiffs’ expert witnesses offered opinions about the children’s future risk of cancer that were truly over the top. Dahlgren testified that the children were “highly likely” to develop cancer in the future. Slip op. at 6. Ryer-Powder claimed that the children’s exposures were “sufficient to present an unacceptable risk of cancer in the future.” Slip op. at 10. With no competence evidence to support their claims of present or past injury, these opinions about future cancer were no longer relevant. The Circuit thus missed an opportunity to comment on how meaningless these opinions were. Most people will develop a cancer at some point in their lifetime, and we might all agree that any risk is unacceptable, which is why medical research continues into the causes, prevention, and cure of cancer. An unquantified risk of cancer, however, cannot support an award of damages even if it were a proper item of damages. See, e.g., Sutcliffe v. G.A.F. Corp., 15 Phila. 339, 1986 Phila. Cty. Rptr. LEXIS 22, 1986 WL 501554 (1986). See also “Back to Baselines – Litigating Increased Risks” (Dec. 21, 2010).

[1] Steven J. Smith, et al., “Molecular Epidemiology of p53 Protein Mutations in Workers Exposed to Vinyl Chloride,” 147 Am. J. Epidemiology 302 (1998) (average level of workers’ exposure was 3,735 parts per million; children were supposedly exposed at 3 ppb). This study looked only at a putative biomarker for angiosarcoma of the liver, not at cancer risk.

[2] Cesare Maltoni, et al., “Carcinogenity Bioassays of Vinyl Chloride Monomer: A Model of Risk Assessment on an Experimental Basis, 41 Envt’l Health Persp. 3 (1981).

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Publication of Two Symposia on Scientific Evidence in the Law

August 2nd, 2015

The Journal of Philosophy, Science & Law bills itself as an on-line journal for the interdisciplinary exploration of philsophy, science, and law. This journal has just made its “Daubert Special” issue available at its website:

Jason Borenstein and Carol Henderson, “Reflections on Daubert: A Look Back at the Supreme Court’s Decision,” 15 J. Philos., Sci. & Law 1 (2015)

Mark Amadeus Notturno, “Falsifiability Revisited: Popper, Daubert, and Kuhn,” 15 J. Philos., Sci. & Law 5 (2015)

Tony Ward, “An English Daubert? Law, Forensic Science and Epistemic Deference,” 15 J. Philos., Sci. & Law 26 (2015)

Daniella McCahey & Simon A. Cole, “Human(e) Science? Demarcation, Law, and ‘Scientific Whaling’ in Whaling in the Antarctic” 15 J. Philos., Sci. & Law 37 (2015)

Back in January 30 – 31, 2015, the Texas Law Review called for a Conference on Science Challenges for Law and Policy, to focus on issues arising at intersection of science and law, with particular focus on issues arising in criminal justice, bioethics, and the environment. The Conference schedule is still available here. Conference papers addressed the nature of scientific disputes, the role of expertise in resolving such disputes, and the legal implementation and management of scientific knowledge. Some of the Conference papers are now available in the symposium issue of the 2015 Texas Law Review:

Rebecca Dresser, “The ‘Right to Try’ Investigational Drugs: Science and Stories in the Access Debate,” 93 Tex. L. Rev. 1631

David L. Faigman, “Where Law and Science (and Religion?) Meet,” 93 Tex. L. Rev. 1659 (2015)

Jennifer E. Laurin, “Criminal Law’s Science Lag: How Criminal Justice Meets Changed Scientific Understanding,” 93 Tex. L. Rev. 1751 (2015)

Elizabeth Fisher, Pasky Pascual & Wendy Wagner, “Rethinking Judicial Review of Expert Agencies,” 93 Tex. L. Rev. 1681 (2015)

Sheila Jasanoff, “Serviceable Truths: Science for Action in Law and Policy,” 93 Tex. L. Rev. 1723 (2015)

Thomas O. McGarity, “Science and Policy in Setting National Ambient Air Quality Standards: Resolving the Ozone Enigma,” 93 Tex. L. Rev. 1783 (2015)

Jennifer L. Mnookin, “Constructing Evidence and Educating Juries: The Case for Modular, Made-In-Advance Expert Evidence About Eyewitness Identifications and False Confessions,” 93 Tex. L. Rev. 1811 (2015)

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California Actos Decision Embraces Relative-Risk-Greater-Than-Two Argument

July 28th, 2015

A recent decision of the California Court of Appeal, Second District, Division Three, continues the dubious state and federal practice of deciding important issues under cover of unpublished opinions. Cooper v. Takeda Pharms. America, Inc., No. B250163, 2015 Cal. App. Unpub. LEXIS 4965 (Calif. App., 2nd Dist., Div. 3; July 16, 2015). In Cooper, plaintiff claimed that her late husband’s bladder cancer was caused by defendant’s anti-diabetic medication, Actos (pioglitazone). The defendant moved to strike the expert witness testimony in support of specific causation. The trial judge expressed serious concerns about the admissibility of plaintiff’s expert witnesses on specific causation, but permitted the trial to go forward. After a jury returned its verdict in favor of plaintiff, the trial court entered judgment for the defendants, on grounds that the plaintiff lacked admissible expert witness testimony.

Although a recent, large, well-conducted study[1] failed to find any meaningful association between pioglitazone and bladder cancer, there were, at the time of trial, several studies that suggested an association. Plaintiff’s expert witnesses, epidemiologist Dr. Alfred Neugut and bladder oncologist Dr. Norm Smith interpreted the evidence to claim a causal association, but both conceded that there were no biomarkers that allowed them to attribute Cooper’s cancer to pioglitazone. The plaintiff also properly conceded that identifying a cause of the bladder cancer was irrelevant to treating the disease. Cooper, 2015 Cal. App. Unpub. LEXIS 4965, at *13. Specific causation was thus determined by the so-called process of differential etiology, with the ex ante existence of risk substituting for cause, and using risk exposure in the differential analysis.

The trial court was apparently soured on Dr. Smith’s specific causation assessment because of his poor performance at deposition, in which he demonstrated a lack of understanding of Cooper’s other potential exposures. Smith’s spotty understanding of Cooper’s actual and potential exposures and other risks made any specific causation assessment less than guesswork. By the time of trial, Dr. Smith and plaintiff’s counsel had backfilled the gaps, and Smith presented a more confident analysis of Cooper’s exposures and potentially competing risks.

Cooper had no family history of bladder cancer, no alcohol consumption, and no obvious exposure to occupational bladder carcinogens. His smoking history would account for exposure to a known bladder carcinogen, cigarette smoke, but Cooper’s documented history was of minor tobacco use, and remote in time. Factually, Cooper’s history was suspect and at odds with his known emphysema. Based upon this history, along with their causal interpretation of the Actos bladder cancer association, and their quantitative assessment that the risk ratio for bladder cancer from Actos was 7.0 or higher for Mr. Cooper (controlled for covariate, potential confounders), the plaintiff’s expert witnesses opined that Actos was probably a substantial factor in causing Mr. Cooper’s bladder cancer. The court did not examine the reasonableness of Dr. Smith’s risk ratios, which seem exorbitant in view of several available meta-analyses.[2]

The court stated that under the applicable California law of “substantial factor,” the plaintiff’s expert witness, in conducting a differential diagnosis, need not exclude every other possible cause of plaintiff’s disease “with absolute certainty.” Cooper, at *41-42. This statement leaves unclear and ambiguous whether the plaintiff’s expert witness must (and did in this case) rule out other possible causes with some level of certitude less than “absolute certainty,” such as reasonable medical certainty, or perhaps reasonable probability. Dr. Smith’s testimony, as described, did not attempt to go so far as to rule out smoking as “a cause” of Cooper’s bladder cancer; only that the risk from smoking was a lower order of magnitude than that for Actos. In Dr. Smith’s opinion, the discrepancy in magnitude between the risk ratios for smoking and Actos allowed him to state confidently that Actos was the most substantial risk.

Having estimated the smoking-related increased risk to somewhere between 0 and 100%, with the Actos increased risk at 600% or greater, Dr. Smith was able to present an admissible opinion that Actos was a substantial factor. Of course, this all turns on the appellate court’s acceptance of risk, of some sufficiently large magnitude, as evidence of specific causation. In the Cooper court’s words:

“The epidemiological studies relied on by Dr. Smith indicated exposure to Actos® resulted in hazard ratios for developing bladder cancer ranging from 2.54 to 6.97.18 By demonstrating a relative risk greater than 2.0 that a product causes a disease, epidemiological studies thereby become admissible to prove that the product at issue was more likely than not responsible for causing a particular person’s disease. “When statistical analyses or probabilistic results of epidemiological studies are offered to prove specific causation . . . under California law those analyses must show a relative risk greater than 2.0 to be ‘useful’ to the jury. Daubert v. Merrell Dow Pharmaceuticals Inc., 43 F.3d 1311, 1320 (9th Cir.), cert. denied 516 U.S. 869 (1995) [Daubert II]. This is so, because a relative risk greater than 2.0 is needed to extrapolate from generic population-based studies to conclusions about what caused a specific person’s disease. When the relative risk is 2.0, the alleged cause is responsible for an equal number of cases of the disease as all other background causes present in the control group. Thus, a relative risk of 2.0 implies a 50% probability that the agent at issue was responsible for a particular individual’s disease. This means that a relative risk that is greater than 2.0 permits the conclusion that the agent was more likely than not responsible for a particular individual’s disease. [Reference Manual on Scientific Evidence (Federal Judicial Center 2d ed. 2000) (“Ref. Manual”),] Ref. Manual at 384, n. 140 (citing Daubert II).” (In re Silicone Gel Breast Implant Prod. Liab. Lit. (C.D. Cal. 2004) 318 F.Supp.2d 879, 893; italics added.) Thus, having considered and ruled out other background causes of bladder cancer based on his medical records, Dr. Smith could conclude based on the studies that it was more likely than not that Cooper’s exposure to Actos® caused his bladder cancer. In other words, because the studies, to varying degrees, adjusted for race, age, sex, and smoking, as well as other known causes of bladder cancer, Dr. Smith could rely upon those studies to make his differential diagnosis ruling in Actos®—as well as smoking—and concluding that Actos® was the most probable cause of Cooper’s disease.”

Cooper, at *78-80 (emphasis in the original).

Of course, the epidemiologic studies themselves are not admissible, regardless of the size of the relative risk, but the court was, no doubt, speaking loosely about the expert witness opinion testimony that was based upon the studies with risk ratios greater than two. Although the Cooper case does not change California law’s facile acceptance of risk as a substitute for cause, the case does base its approval of plaintiff’s expert witness’s attribution as turning on the magnitude of the risk ratio, adjusted for confounders, as having exceeded two. The Cooper case leaves open what happens when the risk that is being substituted for cause is a ratio ≤ 2.0. Some critics of the risk ratio > 2.0 inference have suggested that risk ratios greater than two would lead to directed verdicts for plaintiffs in all cases, but this suggestion requires demonstrations of both the internal and external validity of the studies that measure the risk ratio, which in many cases is in doubt. In Cooper, the plaintiff’s expert witnesses’ embrace of a high, outlier risk ratio for Actos, while simultaneously downplaying competing risks, allowed them to make out their specific causation case.

[1] James D. Lewis, Laurel A. Habel, Charles P. Quesenberry, Brian L. Strom, Tiffany Peng, Monique M. Hedderson, Samantha F. Ehrlich, Ronac Mamtani, Warren Bilker, David J. Vaughn, Lisa Nessel, Stephen K. Van Den Eeden, and Assiamira Ferrara, “Pioglitazone Use and Risk of Bladder Cancer and Other Common Cancers in Persons With Diabetes,” 314 J. Am. Med. Ass’n 265 (2015) (adjusted hazard ratio 1.06, 95% CI, 0.89-1.26).

[2] See, e.g., R.M. Turner, et al., “Thiazolidinediones and associated risk of bladder cancer: a systematic review and meta-analysis,” 78 Brit. J. Clin. Pharmacol. 258 (2014) (OR = 1.51, 95% CI 1.26-1.81, for longest cumulative duration of pioglitazone use); M. Ferwana, et al., “Pioglitazone and risk of bladder cancer: a meta-analysis of controlled studies,” 30 Diabet. Med. 1026 (2013) (based upon 6 studies, with median follow-up of 44 months, risk ratio = 1.23; 95% CI 1.09-1.39); Cristina Bosetti, “Cancer Risk for Patients Using Thiazolidinediones for Type 2 Diabetes: A Meta-Analysis,” 18 The Oncologist 148 (2013) (RR = 1.64 for longest exposure); Shiyao He, et al., “Pioglitazone prescription increases risk of bladder cancer in patients with type 2 diabetes: an updated meta-analysis,” 35 Tumor Biology 2095 (2014) (pooled hazard ratio = 1.67 (95% C.I., 1.31 – 2.12).

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Canadian Judges’ Reference Manual on Scientific Evidence

July 24th, 2015

I had some notion that there was a Canadian version of the Reference Manual on Scientific Evidence in the works, but Professor Greenland’s comments in a discussion over at Deborah Mayo’s blog drew my attention to the publication of the Science Manual for Canadian Judges [Manual]. See “‘Statistical Significance’ According to the U.S. Dept. of Health and Human Services (ii),” Error Statistics Philosophy (July 17, 2015).

The Manual is the product of the Canadian National Judicial Institute (NJI), which is an independent, not-for-profit group that is committed to educating Canadian judges. The NJI’s website describes the Manual:

“Without the proper tools, the justice system can be vulnerable to unreliable expert scientific evidence.

* * *

The goal of the Science Manual is to provide judges with tools to better understand expert evidence and to assess the validity of purportedly scientific evidence presented to them. …”

The Chief Justice of Canada, Hon. Beverley M. McLachlin, contributed an introduction to the Manual, which was notable for its frank admission that:

“[w]ithout the proper tools, the justice system is vulnerable to unreliable expert scientific evidence.

****

Within the increasingly science-rich culture of the courtroom, the judiciary needs to discern ‘good’ science from ‘bad’ science, in order to assess expert evidence effectively and establish a proper threshold for admissibility. Judicial education in science, the scientific method, and technology is essential to ensure that judges are capable of dealing with scientific evidence, and to counterbalance the discomfort of jurists confronted with this specific subject matter.”

Manual at 14. These are laudable goals, indeed.

The first chapter of the Manual is an overview of Canadian law of scientific evidence, “The Legal Framework for Scientific Evidence,” by Canadian law professors Hamish Stewart (University of Toronto), and Catherine Piché (University of Montreal). Several judges served as peer reviewers.

The second chapter, “Science and the Scientific Method,” contains the heart of what judges supposedly should know about scientific and statistical matters to serve as effective “gatekeepers.” Like the chapters in the Reference Manual on Scientific Evidence, this chapter was prepared by a scientist author (Scott Findlay, Ph.D., Associate Professor of Biology, University of Ottawa) and a lawyer author (Nathalie Chalifour, Associate Professor of Law, University of Ottawa). Several judges, and Professor Brian Baigrie (University of Toronto, Victoria College, and the Institute for the History and Philosophy of Science and Technology) provided peer review. The chapter attempts to cover the demarcation between science and non-science, and between scientific and other expert witness opinion. The authors describe “the” scientific method, hypotheses, experiments, predictions, inference, probability, statistics and statistical hypothesis testing, data reliability, and related topics. A subsection of chapter two is entitled “Normative Issues in Science – The Myth of Scientific Objectivity,” which suggests a Feyerabend, post-modernist influence at odds with the Chief Justice’s aspirational statement of goals in her introduction to the Manual.

Greenland noted some rather cavalier statements in Chapter two that suggest that the conventional alpha of 5% corresponds to a “scientific attitude that unless we are 95% sure the null hypothesis is false, we provisionally accept it.” And he pointed elsewhere where the chapter seems to suggest that the coefficient of confidence that corresponds to an alpha of 5% “constitutes a rather high standard of proof,” thus confusing and conflating probability of random error with posterior probabilities. Some have argued that these errors are simply an effort to make statistical concepts easier to grasp for lay people, but the statistics chapter in the FJC’s Reference Manual shows that accurate exposition of statistical concepts can be made understandable. The Canadian Manual seems in need of some trimming with Einstein’s razor, usually paraphrased as “Everything should be made as simple as possible, but no simpler.”[1] The razor should certainly applied to statistical concepts, with the understanding that pushing to simplify too aggressively can sometimes result in simplistic, and simply wrong, exposition.

Chapter 3 returns to more lawyerly matters, “Managing and Evaluating Expert Evidence in the Courtroom,” prepared and peer-reviewed by prominent Canadian lawyers and judges. The final chapter, “Ethics of the Expert Witness,” should be of interest to lawyers and judges in the United States, where the topic is largely ignored. The chapter was prepared by Professor Adam Dodek (University of Ottawa), along with several writers from the National Judicial Institute, the Canadian Judicial Council, American College of Trial Lawyers, Environment Canada, and notably, Joe Cecil & the Federal Judicial Center.

Weighing in at 228 pages, the Science Manual for Canadian Judges is much shorter than the Federal Judicial Center’s Reference Manual on Scientific Evidence. Unlike the FJC’s Reference Manual, which is now in its third edition, the Canadian Manual has no separate chapters on regression, DNA testing and forensic evidence, clinical medicine and epidemiology. The coverage of statistical inference is concentrated in chapter two, but that chapter has no discussion of meta-analysis, systematic review, evidence-based medicine, confounding, and the like. Perhaps there will soon be a second edition of the Science Manual for Canadian Judges.

[1] See Albert Einstein, “On the Method of Theoretical Physics; The Herbert Spencer Lecture,” delivered at Oxford (10 June 1933), published in 1 Philosophy of Science 163 (1934) (“It can scarcely be denied that the supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a single datum of experience.”).

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