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The IARC Announces Water Causes Cancer

June 18th, 2016

Well, drinking water very hot, or other scalding beverages, probably does cause cancer. Earlier this week, the International Agency for Research on Cancer (IARC) issued a press release that one of its working groups had reviewed the data on the carcinogencity of coffee, maté, and very hot beverages, and concluded that maté, which is often served very hot, “probably” causes esophageal cancer. IARC Press Release N° 244, “IARC Monographs evaluate drinking coffee, maté, and very hot beverages” (June 15, 2016). Very hot beverages were rated 2A, for their probably causing human esophageal cancer.

The good news is that “probably” does not mean “more likely than not” in IARC-speak, and the working group was evaluating hazard not risk.[1] IARC classifications do not attempt to quantify the magnitude of risk that may result from exposure to a classified “hazard.” Id. at Note to the Editor. Because all empirical propositions have a probability of being true, somewhere between 0 and 100%, (with P ≠ 0; P ≠ 100%), the IARC classifications of “probably” causing cancer are probably not particularly meaningful.  Everything “probably” causes cancer in this sense. See Ed Yong, “Beefing With the World Health Organization’s Cancer Warnings,” The Atlantic (Oct 26, 2015).

The IARC group’s evaluation of “very hot drinks” accords with the World Health Organization’s Technical Report Series 916 on Diet, Nutrition and the Prevention of Chronic Diseases, which recommends against consumption of scalding hot temperatures. See Anahad O’Connor, “Coffee May Protect Against Cancer, W.H.O. Concludes,” N.Y. Times (June 15, 2016)[O’Connor]. As though people, other than McDonald’s coffee drinkers, needed such a recommendation. The IARC group found no conclusive evidence to implicate drinking cold maté, or maté at temperatures below scalding levels.

An IARC Decision We Can Like a Latte

The Working Group found no conclusive evidence for a carcinogenic effect of drinking coffee, and placed coffee in its category 3, “not classifiable” with respect to carcinogenicity.[2] The working group’s evaluation included over 1,000 observational and experimental studies, including randomized trials, and found no evidence to support the claims that coffee causes human cancer. The IARC also found a good deal of evidence supporting the claim that drinking coffee reduces the risk of various human cancers.

There is a Group 4, for exposures probably not carcinogenic in humans, but in its 45 years of evaluations, the IARC has found only one substance on Planet Earth, which does not cause cancer:  caprolactam.  Perhaps after another 1,000 studies, coffee will reach this exalted category. For now, coffee is unclassifiable with “inadequate” evidence of human carcinogenicity in the IARC’s view.

The New York Times, not particularly expertly, and without supporting citations, declared that the evidence for coffee’s health benefits could not establish actual causation of benefit because the data came from epidemiologic studies.  See O’Conner. This would not be the first time that the New York Times made up things.

In 1991, the IARC evaluated coffee drinking as a “possible” human carcinogen (Group 2B), based upon limited evidence of an association with urinary bladder cancer in case-control studies, and some evidence in experimental animals.[3] This year’s evaluation of coffee as Group 3 thus represents a rare reversal of opinion, in the face of additional evidence, from the IARC.

[1] The IARC Preamble definition of probable reveals that “probable” does not mean greater than 50%. See also “The IARC Process is Broken” (May 4, 2016).

[2] See Dana Loomis, Kathryn Guyton, Yann Grosse, Béatrice Lauby-Secretan, Fatiha El Ghissassi, Véronique Bouvard, Lamia Benbrahim-Tallaa, Neela Guha, Heidi Mattock, Kurt Straifon behalf of the IARC Monograph Working Group, “Carcinogenicity of drinking coffee, mate, and very hot beverages,” Lancet Oncology (2016 in press).

[3] IARC, “Coffee, tea, mate, methylxanthines and methylglyoxal,” 51 IARC Monogr Eval Carcinog Risks Humans 1 (1991).

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The Webb of Unsophistication in Products Liability Law

May 29th, 2016

The Heart of the Matter

The classic early cases in products liability law were about consumers hurt by consumer products, sold by manufacturers or dealers directly to consumers. The key component of these cases was inequality of bargaining power, of knowledge about latent defects or hazards, and of control over the discovery of latent hazards or defects. American products liability law was created around consumer products.  Just think of Henningsen, Escola, and MacPherson.[1]  These were all consumer products for which the rhetoric about inequality of bargaining, knowledge, and control over design, manufacturing, and latent hazards sometimes makes sense. The paradigmatic model for products liability, however, frequently does not work for the three-way relationship of sales of products to large industrial employers. The model especially does not work when the product is a raw material used throughout a factory, or incorporated into another product.

Many courts have failed to come to grips with the inadequacy of the consumer model for products liability cases in instances of occupational harm to industrial employees.  Courts have been trying to ram this square peg into a round hole since the early asbestos litigation (which perhaps made some sense because there was inequality between Johns Manville and most vendees), but makes no sense when John Manville is itself the purchaser.

The Tangled Webb in California Law

The Webb case received some attention after the California Court of Appeals reversed a trial court’s entry of JNOV for defendant Special Electric on the so-called sophisticated intermediary defense.  See “California Supreme Court Set To Untangle Webb” (July 7, 2013); “Big Blue & The Sophisticated User and Intermediary Defenses” (Sept. 27, 2014); G. Jeff Coons, “What a Tangled Webb We Weave: Court Imposes Failure to Warn Liability On Supplier to Johns-Manville” (April 2013). Special Electric petition for review, and eventually the California Supreme Court called for full briefing and oral argument in the Webb case.

The wheels of justice grind slowly in California. Special Electric filed its opening brief on the merits, on September 10, 2013. Webb’s widow answered in December 2013, and Special Electric replied in February 2014. Several amici curiae joined the fray in April 2014. Mark A. Behrens filed a brief on behalf of the Coalition for Litigation Justice, Inc., Chamber of Commerce, NFIB Small Business Legal Center, and American Chemistry Council. The Pacific Legal Foundation also filed, as did Elementis Chemicals Inc.

After mulling over the briefs for two years, the California Supreme Court heard argument on March 1, 2016, and then in surprisingly short order, affirmed the intermediate appellate, earlier this week. The Supreme Court’s ruling upheld a Court of Appeal’s decision that reversed a judgment for defendant Special Electric, based upon a jury verdict in favor of William Webb, who was exposed to crocidolite sold by Special Electric, and which caused him to develop mesothelioma in 2011. The Supreme Court’s opinion[2] held that sophisticated intermediary doctrine was a complete legal defense, even potentially for an asbestos supplier, but declined to apply it to the benefit of Special Electric, which had misrepresented facts about crocidolite and offered no evidence that its purchaser was sophisticated about crocidolite asbestos and its unique relationship with mesothelioma. [Slip opinion cited here as Webb.] Webb v. Special Elec. Co., Inc., 2016 BL 163642, Cal., No. S209927, 5/23/16).

The majority opinion[3] fortunately was able to separate the poorly framed and supported defense by Special Electric from the basic tenets of tort law and the sophisticated intermediary defense. To the extent that anyone doubted the validity of the sophisticated intermediary defense, the Webb Court formally adopted the doctrine as the law of California, as set out in the Second and Third Restatements of Tort Law. Webb at 15-16. According to the Court, a defendant may set up sophisticated intermediary doctrine as a complete defense, to failure to warn claims for known or knowable product risks, sounding in negligence or in strict liability, when the defendant supplier:

“(1) provides adequate warnings to the product’s immediate purchaser, or sells to a sophisticated purchaser that it knows is aware or should be aware of the specific danger, and

(2) reasonably relies on the purchaser to convey appropriate warnings to downstream users who will encounter the product.”

Webb at 16 (emphasis in original).[4]

As an affirmative defense, the defendant supplier must carry its burden of showing that it adequately warned the intermediary, or that it knew the intermediary knew or should have known of the specific hazard, and that it reasonably relied upon the purchaser to transmit warnings. Id.

On appeal, the California Supreme Court held that defendant Special Electric failed to preserve its entitlement to the sophisticated intermediary defense because “it never attempted to show that it actually or reasonably relied on Johns-Manville to warn end users. Nor did Special Electric request a jury instruction or verdict form question on the sophisticated intermediary doctrine.” Webb at 23.

Alternatively, on the assumption that Special Electric preserved the defense, the Court held that this defendant failed to establish the defense as a matter of law because:

“[a]lthough the record clearly shows Johns-Manville was aware of the risks of asbestos in general, no evidence established it knew about the particularly acute risks posed by the crocidolite asbestos Special Electric supplied. In addition, plaintiffs presented evidence that at least one Special Electric salesperson told customers crocidolite was safer than other types of asbestos fiber, when the opposite was true.”

Webb at 23.

The Webb Court reviewed the Tort Restatements’ embrace of the sophisticated intermediary defense in both the Second and Third editions.  The Webb Court noted that the Third Restatement demonstrated the continued validity and vitality of the defense, as had been expressed in the Section 388 of the Restatement Second of Torts.[5] The Court noted and followed the Third Restatement’s recitation of guiding considerations for invoking and sustaining the defense:

“There is no general rule as to whether one supplying a product for the use of others through an intermediary has a duty to warn the ultimate product user directly or may rely on the intermediary to relay warnings. The standard is one of reasonableness in the circumstances. Among the factors to be considered are the gravity of the risks posed by the product, the likelihood that the intermediary will convey the information to the ultimate user, and the feasibility and effectiveness of giving a warning directly to the user.”

Webb at 15 (citing Restatement 3d Torts, Products Liability, § 2, com. i, at p. 30.) Citing California precedent, the Webb Court noted that

“[t]he focus of the [sophisticated intermediary] defense . . . is whether the danger in question was so generally known within the trade or profession that a manufacturer should not have been expected to provide a warning specific to the group to which plaintiff belonged.”

Webb at 9-10 (quoting from Johnson v. American Standard, Inc. 43 Cal.4th 56, 72 (2008).  The pertinent legal test is whether a reasonable supplier would have known of the intermediary’s sophistication with respect to the relevant risk. Webb at 20.[6] Of course, the existence of a pervasive regulatory control of risk creation, detection, and mitigation in the workplace would count heavily in this objective test.  “Every person has a right to presume that every other perform his duty and obey the law.” Webb at 21 (internal citation omitted) (emphasis added).

The Restatement factors, however, did not support Special Electric’s invocation of the defense in a case involving:

(1) crocidolite asbestos, one of the most hazardous substances known,

(2) defendant’s affirmative and blatantly false misrepresentations of the relative safety of crocidolite relative to chrysotile asbestos,[7] and

(3) a complete failure of proof that the purchaser, Johns Manville, knew that crocidolite was especially hazardous with respect to the causation of mesothelioma.

Webb at 23-24. Factors one and two were givens for defense counsel, but factor three speaks to unnecessary coyness on the part of the defense.  Showing that Johns Manville was well aware of the extraordinarily great hazard of crocidolite would have been relatively easy to do from past transcripts, articles, speeches, and litigation conduct of the Johns Manville companies. Despite the extreme hazards from uncontrolled asbestos exposures, the Webb case explained that the sophisticated intermediary defense was not per se inapplicable to asbestos cases, and went so far as to disapprove an earlier California Court of Appeals decision that refused to apply the defense in the asbestos personal injury context when no warnings had been given.[8] “Sophistication obviates the need for warnings because a sophisticated purchaser already knows or should know of the relevant risks.” Webb at 17-18.

The Webb case acknowledged that defective design claims against raw material suppliers are incoherent and invalid, whether for the raw material itself, or for downstream design defect claims against for the product with the incorporated raw material. “[A] basic raw material such as sand, gravel, or kerosene cannot be defectively designed.” Webb at 11-12 (quoting from Restatement 3d Torts, Products Liability, § 5, com. c, at p. 134).[9]

The Webb Court also evinced a healthy disrespect for the notion that tort law is only about spreading risk and compensating injured persons. The Court acknowledged that in some instances, there were competing policies of compensating persons injured by products and “encouraging conduct that can feasibly be performed.” Webb at 2. The Court also acknowledged that there were hazards to warning when none was needed or when the absence of a warning would not be a legal cause of harm:

“Because sophisticated users already know, or should know, about the product’s dangers, the manufacturer’s failure to warn is not the legal cause of any harm. A sophisticated user’s knowledge is thus the equivalent of prior notice. The defense serves public policy, because requiring warnings of obvious or generally known product dangers could invite consumer disregard and contempt for warnings in general.”

Webb at 9 (internal citations omitted) (emphasis added). Furthermore, the sophisticated intermediary defense balances the need for the worker-consumer’s safety with “the practical realities of supplying products.” Webb at 17.

The Webb decision puts California in line with the majority rule that recognizes the validity of the sophisticated intermediary defense, and embraces real-world truth that:

“[in] some cases, the buyer’s sophistication can be a substitute for actual warnings, but this limited exception only applies if the buyer was so knowledgeable about the material supplied that it knew or should have known about the particular danger.”

Webb at 17.[10] The Court noted and agreed with the Restatement Third’s observation that imposing liability upon raw material suppliers for failure to warn can be unduly and unfairly burdensome when such liability would require remote suppliers

“to develop expertise regarding a multitude of different end-products and to investigate the actual use of raw materials by manufacturers over whom the supplier has no control.”

Webb at 12 (quoting from Restatement 3d Torts, Products Liability, § 5, com. c, at p. 134).

Concurrence

Chief Justice Tani Gorre Cantil-Sakauye, along with Justice Ming W. Chin, concurred in the result, but dissented from the majority’s rationale as overly broad. The concurring justices insisted that a supplier reasonably relies upon its purchaser only when the purchaser has actual awareness of the product’s risks. Webb concurrence at 4. Even this stingier approach noted that one of the purpose of warnings is

“to enable the consumer or others who might come in contact with the product to choose not to expose themselves to the risks presented.”

Webb Concurrence at 3 (citing Restatement3d Torts, Products Liability, § 2, com. i, at p. 30).  In many sophisticated intermediary contexts involving occupational exposures to fumes, vapors, and dusts, workers (consumers) cannot appreciate whether they might come in contact with the product such that they have actual risks unless the sophisticated intermediary measures its specific workplace exposures, given its actual engineering, administrative, and person protection controls.

Commentary

The Webb Court failed to address in any meaningful form how Special Electric could discharge a duty to warn Mr. Webb directly, when it sold blue asbestos to Johns-Manville, which then incorporated that fiber, along with other recycled asbestos into transite pipes. To this extent, the Webb decision carries forward the glib belief in efficacy of warnings, without any evidence or critical thought.

It is hard to imagine an industrial purchaser that was unaware of the special hazards of crocidolite by 1970, and yet Special Electric apparently failed to offer evidence on the issue whether Johns-Manville had such awareness. A court might take judicial notice of Johns-Manville sophistication, but there is not even the suggestion that Special Electric attempted to supplement the vacuous record with a request for judicial notice.

If the California Supreme Court’s recitation of the facts of the case is correct, then we are left with an unflattering inference about Special Electric’s trial strategy and execution.  Perhaps Special Electric was coyly trying to avoid a downside outcome in which it was responsible for 99.99% of the verdict because its blue asbestos was by far the most important cause of Mr. Webb’s tragic disease, a disease that would have almost certainly been avoided had never had exposure to blue asbestos. The propensity of crocidolite to cause mesothelioma is orders of magnitude greater than chrysotile, which by itself may not even be a competent cause of the harm suffered by Mr. Webb.

In the final analysis, the Webb Court correctly adopted the sophisticated intermediary principle as an essential limit to tort liability, but denied its benefit to Special Electric.  The sophisticated intermediary doctrine should not, however, be conceived of as an affirmative defense.  The scope of the rule is defined by the rationale for its existence, and the sophisticated intermediary situation lies outside the realm and rationale of protecting, by warning, consumers against latent hazards.  It is time that courts recognize that much litigation brought to its doors is really the result of labor-management issues within the workplace, and not the doings or responsibility of remote suppliers of raw materials.

[1] See, e.g, MacPherson v. Buick Motor Co., 217 N.Y. 382, 111 N.E. 1050 (1916) (holding that privity of contract did not bar suit and that product manufacturers could be liable to consumers for injuries); Henningsen v. Bloomfield Motors, Inc., 32 N.J. 358, 161 A.2d 69 (1960); Escola v. Coca Cola Bottling Co., 24 Cal. 2d 453, 150 P. 2d 436  (1944).

[2] See Steven Sellers, “California Ruling Defines Asbestos Supplier’s Duty to Warn,” BNA Product Safety & Liability Reporter (May 24, 2016).

[3] The majority opinion was written by Associate Justice Carol A. Corrigan, and joined by Associate Justices Kathryn Mickle Werdegar, Goodwin Liu, Mariano-Florentino Cuéllar and Leondra R. Kruger.

[4] See also Webb at 2 (“Under the sophisticated intermediary doctrine, the supplier can discharge this duty if it conveys adequate warnings to the material’s purchaser, or sells to a sufficiently sophisticated purchaser, and reasonably relies on the purchaser to convey adequate warnings to others, including those who encounter the material in a finished product. Reasonable reliance depends on many circumstances, including the degree of risk posed by the material, the likelihood the purchaser will convey warnings, and the feasibility of directly warning end users.”); Webb at 6 (“[T]he sophisticated intermediary doctrine provides that a supplier can discharge its duty to warn if it provides adequate warnings, or sells to a sufficiently sophisticated buyer, and reasonably relies on the buyer to warn end users about the harm.”). Webb at 17 (“If a purchaser is so knowledgeable about a product that it should already be aware of the product’s particular dangers, the seller is not required to give actual warnings telling the buyer what it already knows.”).

[5] See Webb at 15 (“The drafters intended this comment to be substantively the same as section 388, comment n, of the Restatement Second of Torts.”) (citing Restatement 3d Torts, Products Liability, § 2, com. i, reporter’s note 5, at p. 96; Humble Sand & Gravel Inc. v. Gomez, 146 S.W.3d 170, 190 (Tex. 2004). See also Webb at 9 (citing Restatement 2d Torts, § 388 (b), com. k, at pp. 306-307) (“Courts have interpreted section 388, subdivision (b), to mean that if the manufacturer reasonably believes the user will know or should know about a given product’s risk”).

[6] Relevant considerations may include the general dissemination of knowledge of relevant risks, the intermediary’s knowledge of those risks, and the intermediary’s reputation for care. Webb at 20.

[7] Webb at 3, 23.

[8] See Webb at 17-18 (disapproving of the holding in Stewart v. Union Carbide Corp., 190 Cal. App. 4th 23, 29-30 (2010)).

[9] See also Webb at 12 (quoting from Restatement 3d Torts, Products Liability, § 5, com. c, at p. 134) (“Inappropriate decisions regarding the use of such materials are not attributable to the supplier of the raw materials but rather to the fabricator that puts them to improper use.”).

[10] citing approvingly Cimino v. Raymark Industries, Inc., 151 F.3d 297, 334 (5th Cir. 1998) (holding that raw asbestos supplier did not need to warn asbestos product manufacturer Fibreboard, which was “a sophisticated, expert, and knowledgeable manufacturer” of insulation products, about asbestos risks); Higgins v. E.I. DuPont de Nemours & Co., 671 F. Supp. 1055, 1061-1062  (D. Md. 1987) (exculpating supplier when purchaser was a highly sophisticated manufacturer with knowledge from independent sources, as well as its suppliers), aff’d, 863 F.2d 1162 (4th Cir. 1988).

Posted in Asbestos, Silica, Sophisticated User | Comments Off on The Webb of Unsophistication in Products Liability Law

Credible Incredulity

May 19th, 2016

Has skepticism become a victim of political correctness and adversarial zeal?

In the last century, philosopher Bertrand Russell advanced intelligent skepticism against myriad enthusiams and mindless beliefs, political, religious, and pseudo-scientific. Russell saw unwarranted certainty as a serious intellectual offense:

“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.”

Bertrand Russell, “The Triumph of Stupidity” (1933), Mortals and Others: Bertrand Russell’s American Essays, 1931-1935 , at 28 (1998).  When many American intellectuals were still in their love swoon over Stalin, Russell chastised the Soviet dictator for his betrayal of ideals and his enslavement of Eastern European. Stalinism’s certainty about politics and science was not a virtue, but a grave sin.  Or, in Russell’s words:

“One of the painful things about our time is that those who feel certainty are stupid, and those with any imagination and understanding are filled with doubt and indecision.”

Bertrand Russell, New Hopes for a Changing World at 4-5 (1951).

In the 21st century, ideologues of various stripes have tried to silence healthy skepticism and doubt by claiming that their critics have “manufactured doubt.”[1] This aggression against skepticism and doubt, joined with a biased conception of conflicts of interest, have become part of a concerted campaign to privilege tendentious scientific claims from critical scrutiny.

Philosopher Susan Haack, who has aligned herself on occasion with these politicized acolytes of certainty,[2] recently has pushed back, with a reminder that credulity for unwarranted claims, in all walks of life, is unethical.[3]  Haack’s essay is a delightful effort to clarify what credulity is, and to explore why credulity is an epistemologic vice and a social hazard, as well as the implications for citizens and scientists of living in an evidence-based, not a faith-based world.

Drawing inspiration from the the English mathematician and philosopher, William Kingdon Clifford, Haack has adopted one of Clifford’s bon mots as her motto:

“The credulous man is father to the liar and the cheat.”[4]

Indeed! And credulous judges and juries are the parents to specious claims and shyster lawyers.

Clifford’s essay should be required reading for politicians, judges, regulators, and legislators who evaluate the claims of scientist advocates.  Spurning ethical relativism, Clifford identified the key intellectual “sin” in an evidence-based world:

 “It is wrong always, everywhere, and for anyone, to believe anything upon insufficient evidence.”

William K. Clifford, “The Ethics of Belief,” 29 Contemporary Rev. 289, 295 (1877).

Professor Haack should be commended for her fulsome irony for publishing in a journal of one of the world’s more credulous institutions, and for reminding us that credulity is an intellectual vice.

[1] See, e.g., David Michaels, Doubt is Their Product: How Industry’s Assault on Science Threatens Your Health (2008); Naomi Oreskes and Erik M. Conway, Merchants of Doubt: How a Handful of Scientists Obscured the Truth on Issues from Tobacco Smoke to Global Warming (2010).

[2] See, e.g., “Bendectin, Diclegis & The Philosophy of Science” (Oct. 26, 2013).

[3] Susan Haack, “Credulity and Circumspection: Epistemological Character and the Ethics of Belief,” 88 Proc. Am. Catholic Philosophical Ass’n 27 (2015).

[4] citing and quoting William K. Clifford, “The Ethics of Belief ” (1877), in Leslie Stephen and Sir Frederick Pollock, eds., The Ethics of Belief and Other Essays 70, 77 (London 1947).

Posted in Scientific Evidence, Scientific Misconduct | Comments Off on Credible Incredulity

Ancient Truths

May 5th, 2016

David Sackett, in some paternity disputes called the “father of evidence-based medicine,” supposedly once claimed that:

“Half of what you’ll learn in medical school will be shown to be either dead wrong or out of date within five years of your graduation; the trouble is that nobody can tell you which half–so the most important thing to learn is how to learn on your own.”

See Ivan Oransky, “So how often does medical consensus turn out to be wrong?” Retraction Watch (July 11, 2011). Sackett’s meta-statement was itself certainly not “evidence based,” but his point is well taken. Time ultimately erodes the authority of the truthiest sounding claims to medical knowledge. Sara Teichholtz, “The Differential: Half of What You’re Learning is Wrong,” (Dec. 14, 2013). Only lawyers and theologians would think that a statement in an old document or text, once authenticated, has some claim on us as the “truth.”

The Federal Rules of Evidence provide an exception to the rule against hearsay for statements made in ancient documents, those at least twenty years old. Rule 803(16). In 2015, the Judicial Conference’s Committee on Rules of Practice and Procedure proposed retiring the ancient document hearsay rule.[1] The exception created for documents authenticated as “ancient” (> 20 years old) is so inimical to the truth-finding function of trials, that courts strain to avoid finding the documents “authenticated.” See, e.g., Kalamazoo River Study Group v. Menasha Corp., 228 F.3d 648 (6th Cir. 2000).

The proposal to abolish this dangerous exception to the rule against hearsay has engendered resistance from some quarters over its ability to eliminate otherwise admissible evidence in cases involving long-past events, such as environmental or occupational disease litigation. The resistance, however, is misguided.  The Committee’s proposal would not affect the authenticity presumption of an “ancient document,” and such documents could still be used to show state of mind, intention, motive, or notice. If the asserted statement in the old document is actually true, then there is likely much more recent, robust evidence to support the statement. The rule as it now stands is capable of a great deal of mischief.  The fact that a document has survived intact in a place where one would expect to find it may add to its presumptive authenticity, but in many technical, scientific, and medical contexts, the “ancient” provenance actually makes the content likely to be false. Technical and scientific facts and opinions have changed too quickly to endorse statements simply because of they were written down somewhere, over 20 years ago. See “Time to Retire Ancient Documents As Hearsay Exception” (Aug. 23, 2015).

Although many in the legal academy have voiced opposition to the proposal[2], one law professor, Daniel Capra, has astutely observed that we will soon have a flood of easily authenticated documents of doubtful veracity, called websites, and other electronic documents, which have reached the age of evidentiary majority. Daniel J. Capra, “Electronically Stored Information and the Ancient Documents Exception to the Hearsay Rule: Fix It Before People Find Out About It,” 17 Yale J.L. & Tech 1 (2015). The truth of a proposition requires more than the lapse of 20 years since some nincompoop wrote it down.

[1] Preliminary Draft of Proposed Amendments to the Federal Rules of Bankruptcy Procedure and the Federal Rules of Evidence (Aug. 2015); See also Debra Cassens Weiss, “Federal judiciary considers dumping ‘ancient documents’ rule,” ABA Journal Online (Aug. 19, 2015).

[2] Peter Nicolas, “Saving an Old Friend From Extinction: A Proposal to Amend Rather Than to Abrogate the Ancient Documents Hearsay Exception,” 63 UCLA L. Rev. Disc. 172 (2015).

Posted in Evidence, State of the Art | Comments Off on Ancient Truths

The IARC Process is Broken

May 4th, 2016

Last spring, the International Agency for Research on Cancer (IARC) convened a working group that voted to classify the herbicide glyphosate as “probably carcinogenic to humans.” The vote was followed by IARC’s Press Release, a summary in The Lancet,[1] and the publication of a “monograph,” volume 112 in the IARC series.

IARC classifications of a chemical as “probably” carcinogenic to humans are actually fairly meaningless exercises in semantics, not science. A close reading of the IARC Preamble definition of probable reveals that probable does not mean greater than 50%:

“The terms probably carcinogenic and possibly carcinogenic have no quantitative significance and are used simply as descriptors of different levels of evidence of human carcinogenicity, with probably carcinogenic signifying a higher level of evidence than possibly carcinogenic.”

Despite the vacuity of the IARC’s “probability” determinations, IARC decisions have serious real-world consequences in the realm of regulation and litigation. Monsanto, the manufacturer of glyphosate herbicide, reacted strongly, expressing “outrage” and claiming that the IARC had cherry picked data to reach its conclusion. Jack Kaskey, “Monsanto ‘Outraged’ by Assessment That Roundup Probably Causes Cancer,” 43 Product Safety & Liability Reporter 416 (Mar. 30, 2015).

In the wake of the IARC classification, in the fall of 2015, the United States Environmental Protection Agency (EPA) reviewed the evidence for, and against, glysophate’s carcinogenicity. The EPA found that the IARC had deliberately failed to consider studies that did not find associations, and that the complete scientific record did not support a conclusion of human carcinogenicity. EPA Report of the Cancer Assessment Review Committee on Glyphosate (Oct. 1, 2015).

For undisclosed reasons, however, the EPA’s report was never made public until a couple of weeks ago, when it showed up briefly on the agency’s website, only to be pulled down after a day or so. See David Schultz, “EPA Panel Finds Glyphosate Not Likely to Cause Cancer,” Product Safety & Liability Reporter (May 03, 2016). No doubt the present Administration viewed a conflict between EPA and IARC, and disparaging comments about the IARC’s “process” to be national security issues.  At the very least, the Administration would not want to undermine the litigation industry’s reliance upon the IARC cherry-picked report.

All joking aside, the incident highlights the problematic nature of the IARC decision process, and the reliance of regulatory agencies on the apparent authority of IARC determinations. The IARC process is toxic and should be remediated.

[1] Kathryn Z Guyton, Dana Loomis, Yann Grosse, Fatiha El Ghissassi, Lamia Benbrahim-Tallaa, Neela Guha, Chiara Scoccianti, Heidi Mattock, Kurt Straif, on behalf of the International Agency for Research on Cancer Monograph Working Group, IARC, Lyon, France, “Carcinogenicity of tetrachlorvinphos, parathion, malathion, diazinon, and glyphosate,” 16 The Lancet Oncology 490 (2015).

 

 

Posted in Causation, Scientific Evidence, Scientific Misconduct | Comments Off on The IARC Process is Broken

Reinventing the Burden of Proof

April 27th, 2016

If lawyers make antic claims that keep the courtrooms busy, law professors make antic proposals to suggest that the law is conceptually confused and misguided, to keep law reviews full.

A few years ago, an article by Professor Edward Cheng claimed that common law courts have failed to grasp the true meaning of burdens of proof. Edward K. Cheng, “Reconceptualizing the Burden of Proof,” 122 Yale L. J. 1254 (2013) [Cheng]. Every law student knows that the preponderance-of-the-evidence standard requires that the party with the burden of proof to establish each element of the claim or defense to a probability greater than 50%. Cheng acknowledges that courts know this as well (citations omitted), but then he goes on to state some remarkable assertions.

First, Cheng suggests that the legal system has engaged in a “casual recharacterization of the burden of proof into p > 0.5 and p > 0.95.” Cheng at 1258. Being charitable, let’s say “characterization” rather than “recharacterization,” for Cheng cites nothing for his suggestion that there was some prior characterization that the law mischievously changed. Cheng at 1258.

Second, Cheng claims that the failure to deal with quantified posterior probabilities is the result of an educational or psychological deficiency of judges and lawyers:

“By comparison, the criminal beyond-a-reasonable-doubt standard is akin to a probability greater than 0.9 or 0.95. Perhaps, as most courts have ruled, the prosecution is not allowed to quantify ‘reasonable doubt’, but that is only an odd quirk of the math-phobic legal system.”

Cheng at 1256 (internal citations omitted). Cheng’s “recharacterization” has given way to his own mischaracterization of the legal system. There is a pandemic math phobia in the legal system, but the refusal to quantify the burden of proof in criminal cases has nothing to do with fear or mathematical incompetence. Most cases simply do not permit any rational or principled quantification of posterior probabilities. And even if they were to allow such a cognitive maneuver, most people, and even judges, cannot map practical certainty, or something like “beyond a reaonable doubt” on to a probability scale of 0 to 1. No less than Judge Jack Weinstein, certainly a friend to the notion that “all evidence is probabilistic,” showed in his informal survey of federal judges of the Eastern District of New York, that judges have no idea of what probability corresponds to the criminal burden of proof:

US v Fatico BoP

U.S. v. Fatico, 458 F.Supp. 388 (E.D.N.Y. 1978). Judge Weinstein’s informal survey showed well enough that there is no real understanding of how to map reasonable doubt or its complement onto a scale of 0 to 1. Furthermore, for the vast majority of cases, there is simply no way to assign meaningful probabilities to events, causes, and states of mind, which make up the elements of claims and defenses in our legal system.

Third, Cheng makes much of the non-existence of absolute probabilities in legal contexts. The word “absolute” is used 14 times in his essay. This point is confusing as stated because no one, to my knowledge, has claimed that the burden of proof is an absolute probability that is stated or arrived at independently of evidence in the case. Plaintiffs and defendants can have burdens of proof and claims and defenses, respectively, but for sake of simplicity, let’s follow Cheng and describe the civil burden of proof as the plaintiff’s burden. The relevant probability is not the absolute probability P(Hπ), but rather the conditional posterior probability: P(Hπ | E).

Fourth, Cheng’s principal innovation, the introduction of a probability ratio as the true meaning and model of the burden of proof has little or no support in case law or in evidence theory. Cheng cites virtually no cases, and only a few selected publications from the world of law reviews. Cheng proposes to recast burdens of proof as a ratio of conditional probabilities of the plaintiff’s and defendant’s “stories.” If the posterior probability of the plaintiff’s story at trial’s end is P(Hπ | E)1, and the defendant’s story is represented as P(Hδ | E), then Cheng argues that the plaintiff has carried his burden of proof whenever

P(Hπ | E) / P(Hδ | E) > 1.0

This innovation seems fundamentally wrong for several reasons. Again, assuming that the plaintiff or the State has the burden of proof, the defendant has none. If the plaintiff presents no evidence, then the numerator will be zero, and the ratio will be zero. The defendant prevails, and Cheng’s theory holds. But if the plaintiff presents some evidence and the defendant presents none, then the ratio is undefined. Alternatively, we may see the ratio in this situation as approaching infinity as a limit as the probability of the defendant’s “story” based upon his evidence approaches zero. On either interpretation of this scenario, the ratio Cheng invents is huge, and yet the plaintiff may well lose as for instance when plaintiff’s case is insufficient as a matter of law.

Cheng’s ratio theory thus fails as a descriptive theory. The theory appears to fail prescriptively as well. In most civil and criminal cases, the finder of fact is instructed that the defendant has no burden of proof and need not present any evidence at all. Even when the defendant has remained silent, and the plaintiff has presented a legally sufficient case, the fact finder may return a verdict for the defendant when the P(Hπ | E) seems too low with respect to the burden of proof.

Let’s consider an example, perhap not too far fetched in some American courtrooms. The plaintiff claims that drug A has caused him to develop Syndrome Z. Plaintiff has no clinical trial, or analytical epidemiologic, or animal evidence to support his claim. All the plaintiff can adduce is a so-called disproportionality analysis based upon the reporting of adverse events to the FDA. The defendant does not present any evidence of safety. The end point of interest in the lawsuit, Syndrome Z, was not observed in the trials, and was never looked for in any epidemiologic or toxicologic study. The defendant thus has no affirmative evidence of safety that counts for P(Hδ | E).

Assuming that the trial court does not toss this claim pretrial on a Rule 702 motion, or on a directed verdict, the defendant must address the plaintiff’s claim and the assertion that P(Hπ | E) > 0. The plaintiff supports his claim and assertion by presenting an expert witness who endorses the validity, accuracy, and probativeness of the disproportionality analysis. The defendant confronts this evidence solely on cross-examination, and not by trying to suggest that the plaintiff’s expert witness’s analysis is actually evidence of safety. The point of the cross-examination is to show that the proferred analysis is not a valid tool and lacks validity, accuracy, and probativeness.

In this situation, the plaintiff’s P(Hπ | E) might have been greater than 0.5 at the end of direct examination, but if defense counsel has done his job, then at the end of the cross-examination, the P(Hπ | E) < 0.5. Perhaps at this stage of the proceedings, P(Hπ | E) < 0.01.

The defendant, having no affirmative evidence of safety, rests without presenting any evidence. P(Hδ | E) = 0. Alas, we cannot say that P(Hδ | E) is the complement of P(Hπ | E). There is, in most cases, way too much room for ignorance, indeterminate, or unknown probability of the P(Hδ). In this hypothetical, however, there is no evidence adduced for safety at all, only very weak and unreliable evidence of harm. The ratio is undefined, but the law would allow the dismissal of the plaintiff’s case, or would affirm a rational fact finder’s return of a defense verdict. And the law should do those things.

Fifth, Cheng commits other errors along the way to arriving at his ratio theory. In one instance, he commits a serious category mistake:

“Looking at the statistical world, we immediately see that characterizing any decision rule as a 0.5 probability threshold is odd. Statisticians rarely attempt to prove the truth of a proposition or hypothesis by using its absolute probability. Instead, hypothesis testing is usually comparative. There is a null hypothesis and an alternative hypothesis, and one is rejected in favor of the other depending on the evidence observed and the consistency of that evidence with the two hypotheses.”

Cheng at 1259 (internal citations omitted; emphasis added).

Again, Cheng is correct insofar as he suggests that statisticians do not often use use absolute probabilities. Attained levels of significance probabilities, whether used in hypothesis testing or otherwise, are conditional probabilities that describe the probability of observing the sample statistic, or one more extreme, based upon the statistical model and posited null hypothesis. Indeed, many methodologically rigorous statisticians and scientists would resist placing a quantified posterior probability on the truth of a proposition or hypothesis. The measures of probability may be helpful in identifying uncertainties due to random error, or even on occasion due to bias, but these measures do not translate into assigning the quantified posterior probabilites that Cheng wants and needs to make his ratio theory work. There is nothing, however, odd about using the quantified posterior probability of greater than 50% as a metaphor.

But whence comes rejecting one hypothesis “in favor of” another, as a matter of statistics? The null hypothesis is not accepted in the hypothesis test; rather it was assumed in order to conduct the test. The inference Cheng describes would be improper. In a footnote, Cheng asserts that “classical hypothesis testing strongly favors the null hypothesis,” but this conflates attained level of significance with posterior probabilities. Cheng at 1259 n. 12. Cheng states that “the null hypothesis can be given no specific preference,” in legal contexts, id., but this statement seems to ignore what it means for a party to have a burden of proving facts needed to establish its claim or defense.

Of course, over the course of multiple studies, which look at the issue repeatedly with increasingly precise and valid experiments and studies, and which consistently fail to reject a given null hypothesis, we sometimes do, as a matter of judgment, accept the null hypothesis. This situation has little to do with the Cheng’s ratio theory, however.

1   Where P stands for probability, Hπ for the plaintiff’s “story,” Hδ for the defendant’s story, P(Hπ | E) represents the posterior probability at trial’s end of the plaintiff’s story given the evidence, and P(Hδ | E) represents the posterior probability at trial’s end of the defendant’s story given the evidence.

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Lipitor Diabetes MDL’s Inexact Analysis of Fisher’s Exact Test

April 21st, 2016

Muriel Bristol was a biologist who studied algae at the Rothamsted Experimental Station in England, after World War I.  In addition to her knowledge of plant biology, Bristol claimed the ability to tell whether tea had been added to milk, or the tea poured first and then milk had been added.  Bristol, as a scientist and a proper English woman, preferred the latter.

Ronald Fisher, who also worked at Rothamsted, expressed his skepticism over Dr. Bristol’s claim. Fisher set about to design a randomized experiment that would efficiently and effectively test her claim. Bristol was presented with eight cups of tea, four of which were prepared with milk added to tea, and four prepared with tea added to milk.  Bristol, of course, was blinded to which was which, but was required to label each according to its manner of preparation. Fisher saw his randomized experiment as a 2 x 2 contingency table, from he could calculate the observed outcome (and ones more extreme if there were any more extreme outcomes) using the assumption of fixed marginal rates and the hypergeometric probability distribution.  Fisher’s Exact Test was born at tea time.[1]

Fisher described the origins of his Exact Test in one of his early texts, but he neglected to report whether his experiment vindicated Bristol’s claim. According to David Salsburg, H. Fairfield Smith, one of Fisher’s colleagues, acknowledged that Bristol nailed Fisher’s Exact test, with all eight cups correctly identified. The test has gone on to become an important tool in the statistician’s armamentarium.

Fisher’s Exact, like any statistical test, has model assumptions and preconditions.  For one thing, the test is designed for categorical data, with binary outcomes. The test allows us to evaluate whether two proportions are likely different by chance alone, by calculating the probability of the observed outcome, as well as more extreme outcomes.

The calculation of an exact attained significance probability, using Fisher’s approach, provides a one-sided p-value, with no unique solution to calculating a two-side attained significance probability. In discrimination cases, the one-sided p-value may well be more appropriate for the issue at hand. The Fisher’s Exact Test has thus played an important role in showing the judiciary that small sample size need not be an insuperable barrier to meaningful statistical analysis. In discrimination cases, the one-sided p-value provided by the test is not a particular problem.[2]

The difficulty of using Fisher’s Exact for small sample sizes is that the hypergeometric distribution, upon which the test is based, is highly asymmetric. The observed one-sided p-value does not measure the probability of a result equally extreme in the opposite direction. There are at least three ways to calculate the p-value:

  1. Double the one-sided p-value.
  2. Add the point probabilities from the opposite tail that are more extreme than the observed point probability.
  3. Use the mid-P value; that is, add all values more extreme (smaller) than the observed point probability from both sides of the distribution, PLUS ½ of the observed point probability.

Some software programs will proceed in one of these ways by default, but their doing so does guarantee the most accurate measure of two-tailed significance probability.

In the Lipitor MDL for diabetes litigation, Judge Gergel generally used sharp analyses to cut through the rancid fat of litigation claims, to get to the heart of the matter. By and large, he appears to have done a splendid job. In course of gatekeeping under Federal Rule of Evidence 702, however, Judge Gergel may have misunderstood the nature of Fisher’s Exact Test.

Nicholas Jewell is a well-credentialed statistician at the University of California.  In the courtroom, Jewell is a well-known expert witness for the litigation industry.  He is no novice at generating unreliable opinion testimony. See In re Zoloft Prods. Liab. Litig., No. 12–md–2342, 2015 WL 7776911 (E.D. Pa. Dec. 2, 2015) (excluding Jewell’s opinions as scientifically unwarranted and methodologically flawed). In the Lipitor cases, some of Jewell’s opinions seemed outlandish indeed, and Judge Gergel generally excluded them. See In re Lipitor Marketing, Sales Practices and Prods. Liab. Litig., MDL No. 2:14-mn-02502-RMG, ___ F.Supp. 3d  ___ (2015), 2015 WL 7422613 (D.S.C. Nov. 20, 2015) [Lipitor Jewell], reconsideration den’d, 2016 WL 827067 (D.S.C. Feb. 29, 2016) [Lipitor Jewell Reconsidered].

As Judge Gergel explained, Jewell calculated a relative risk for abnormal blood glucose in a Lipitor group to be 3.0 (95% C.I., 0.9 to 9.6), using STATA software. Also using STATA, Jewell obtained an attained significance probability of 0.0654, based upon Fisher’s Exact Test. Lipitor Jewell at *7.

Judge Gergel did not report whether Jewell’s reported p-value of 0.0654, was one- or two-sided, but he did state that the attained probability “indicates a lack of statistical significance.” Id. & n. 15. The rest of His Honor’s discussion of the challenged opinion, however, makes clear that of 0.0654 must have been a two-sided value.  If it had been a one-sided p-value, then there would have been no way of invoking the mid-p to generate a two-sided p-value below 5%. The mid-p will always be larger than the one-tailed exact p-value generated by Fisher’s Exact Test.

The court noted that Dr. Jewell had testified that he believed that STATA generated this confidence interval by “flip[ping]” the Taylor series approximation. The STATA website notes that it calculates confidence intervals for odds ratios (which are different from the relative risk that Jewell testified he computed), by inverting the Fisher exact test.[3] Id. at *7 & n. 17. Of course, this description suggests that the confidence interval is not based upon exact methods.

STATA does not provide a mid p-value calculation, and so Jewell used an on-line calculator, to obtain a mid p-value of 0.04, which he declared statistically significant. The court took Jewell to task for using the mid p-value as though it were a different analysis or test.  Id. at *8. Because the mid-p value will always be larger than the one-sided exact p-value from Fisher’s Exact Test, the court’s explanation does not really make sense:

“Instead, Dr. Jewell turned to the mid-p test, which would ‘[a]lmost surely’ produce a lower p-value than the Fisher exact test.”

Id. at *8. The mid-p test, however, is not different from the Fisher’s exact; rather it is simply a way of dealing with the asymmetrical distribution that underlies the Fisher’s exact, to arrive at a two-tailed p-value that more accurately captures the rate of Type I error.

The MDL court acknowledged that the mid-p approach, was not inherently unreliable, but questioned Jewell’s inconsistent, selective use of the approach for only one test.[4]  Jewell certainly did not help the plaintiffs’ cause and his standing by having discarding the analyses that were not incorporated into his report, thus leaving the MDL court to guess at how much selection went on in his process of generating his opinions..  Id. at *9 & n. 19.

None of Jewell’s other calculated p-values involved the mid-p approach, but the court’s criticism begs the question whether the other p-values came from a Fisher’s Exact Test with small sample size, or other highly asymmetrical distribution. Id. at *8. Although Jewell had shown himself willing to engage in other dubious, result-oriented analyses, Jewell’s use of the mid-p for this one comparison may have been within acceptable bounds after all.

The court also noted that Jewell had obtained the “exact p-value and that this p-value was not significant.” Id. The court’s notation here, however, does not report the important detail whether that exact, unreported p-value was merely the doubled of the one-sided p-value given by the Fisher’s Exact Test. As the STATA website, cited by the MDL court, explains:

“The test naturally gives a one-sided p-value, and there are at least four different ways to convert it to a two-sided p-value (Agresti 2002, 93). One way, not implemented in Stata, is to double the one-sided p-value; doubling is simple but can result in p-values larger than one.”

Wesley Eddings, “Fisher’s exact test two-sided idiosyncrasy” (Jan. 2009) (citing Alan Agresti, Categorical Data Analysis 93 (2d ed. 2002)).

On plaintiffs’ motion for reconsideration, the MDL court reaffirmed its findings with respect to Jewell’s use of the mid-p.  Lipitor Jewell Reconsidered at *3. In doing so, the court insisted that the one instance in which Jewell used the mid-p stood in stark contrast to all the other instances in which he had used Fisher’s Exact Test.  The court then cited to the record to identify 21 other instances in which Jewell used a p-value rather than a mid-p value.  The court, however, did not provide the crucial detail whether these 21 other instances actually involved small-sample applications of Fisher’s Exact Test.  As result-oriented as Jewell can be, it seems safe to assume that not all his statistical analyses involved Fisher’s Exact Test, with its attendant ambiguity for how to calculate a two-tailed p-value.

Post-Script (Aug. 9, 2017)

The defense argument and the judicial error were echoed in a Washington Legal Foundation paper that pilloried Nicholas Jewell for the surfeit of many methodological flaws in his expert witness opinions in In re Lipitor. Unfortunately, the paper uncritically recited the defense’s theory about the Fisher’s Exact Test:

“In assessing Lipitor data, even after all of the liberties that [Jewell] took with selecting data, he still could not get a statistically-significant result employing a Fisher’s exact test, so he switched to another test called a mid-p test, which generated a (barely) statistically significant result.”

Kirby Griffis, “The Role of Statistical Significance in Daubert/Rule 702 Hearings,” at 19, Wash. Leg. Foundation Critical Legal Issues Working Paper No. 201 (Mar. 2017). See Kirby Griffis, “Beware the Weak Argument: The Rule of Thirteen,” For the Defense 72 (July 2013) (quoting Justice Frankfurter, “A bad argument is like the clock striking thirteen. It puts in doubt the others.”). The fallacy of Griffis’ argument is that it assumes that a mid-p calculation is a different statistical test from the Fisher’s Exact test, which yields a one-tailed significance probability. Unfortunately, Griffis’ important paper is marred by this and other misstatements about statistics.

[1] Sir Ronald A. Fisher, The Design of Experiments at chapter 2 (1935); see also Stephen Senn, “Tea for three: Of infusions and inferences and milk in first,” Significance 30 (Dec. 2012); David Salsburg, The Lady Tasting Tea: How Statistics Revolutionized Science in the Twentieth Century  (2002).

[2] See, e.g., Dendy v. Washington Hosp. Ctr., 431 F. Supp. 873 (D.D.C. 1977) (denying preliminary injunction), rev’d, 581 F.2d 99 (D.C. Cir. 1978) (reversing denial of relief, and remanding for reconsideration). See also National Academies of Science, Reference Manual on Scientific Evidence 255 n.108 (3d ed. 2011) (“Well-known small sample techniques [for testing significance and calculating p-values] include the sign test and Fisher’s exact test.”).

[3] See Wesley Eddings, “Fisher’s exact test two-sided idiosyncrasy” (Jan. 2009), available at <http://www.stata.com/support/faqs/statistics/fishers-exact-test/>, last visited April 19, 2016 (“Stata’s exact confidence interval for the odds ratio inverts Fisher’s exact test.”). This article by Eddings contains a nice discussion of why the Fisher’s Exact Test attained significance probability disagrees with the calculated confidence interval. Eddings points out the asymmetry of the hypergeometric distribution, which complicates arriving at an exact p-value for a two-sided test.

[4] See Barber v. United Airlines, Inc., 17 Fed.Appx. 433, 437 (7th Cir. 2001) (“Because in formulating his opinion Dr. Hynes cherry-picked the facts he considered to render an expert opinion, the district court correctly barred his testimony because such a selective use of facts fails to satisfy the scientific method and Daubert.”).

Posted in Expert Witnesses, Rule 702, statistical evidence | Comments Off on Lipitor Diabetes MDL’s Inexact Analysis of Fisher’s Exact Test

The Education of Judge Rufe – The Zoloft MDL

April 9th, 2016

The Honorable Cynthia M. Rufe is a judge on the United States District Court, for the Eastern District of Pennsylvania.  Judge Rufe was elected to a judgeship on the Bucks County Court of Common Pleas in 1994.  She was appointed to the federal district court in 2002. Like most state and federal judges, little in her training and experience as a lawyer prepared her to serve as a gatekeeper of complex expert witness scientific opinion testimony.  And yet, the statutory code of evidence, and in particular, Federal Rules of Evidence 702 and 703, requires her do just that.

The normal approach to MDL cases is marked by the Field of Dreams: “if you build it, they will come.” Last week, Judge Rufe did something that is unusual in pharmaceutical litigation; she closed the gate and sent everyone home. In re Zoloft Prod. Liab. Litig., MDL NO. 2342, 12-MD-2342, 2016 WL 1320799 (E.D. Pa. April 5, 2016).

Her Honor’s decision was hardly made in haste.  The MDL began in 2012, and proceeded in a typical fashion with case management orders that required the exchange of general causation expert witness reports. The plaintiffs’ steering committee (PSC), acting for the plaintiffs, served the report of only one epidemiologist, Anick Bérard, who took the position that Zoloft causes virtually every major human congenital anomaly known to medicine. The defendants challenged the admissibility of Bérard’s opinions.  After extensive briefings and evidentiary hearings, the trial court found that Bérard’s opinions were riddled with inconsistent assessments of studies, eschewed generally accepted methods of causal inference, ignored contrary evidence, adopted novel, unreliable methods of endorsing “trends” in studies, and failed to address epidemiologic studies that did not support her subjective opinions. In re Zoloft Prods. Liab. Litig., 26 F. Supp. 3d 449 (E.D.Pa.2014). The trial court permitted plaintiffs an opportunity to seek reconsideration of Bérard’s exclusion, which led to the trial court’s reaffirming its previous ruling. In re Zoloft Prods. Liab. Litig., No. 12–md–2342, 2015 WL 314149, at *2 (E.D.Pa. Jan. 23, 2015).

Notwithstanding the PSC’s claims that Bérard was the best qualified expert witness in her field and that she was the only epidemiologist needed to support the plaintiffs’ causal claims, the MDL court indulged the PSC by permitting plaintiffs another bite at the apple.  Over defendants’ objections, the court permitted the PSC to name yet another expert witness, statistician Nicholas Jewell, to do what Bérard had failed to do: proffer an opinion on general causation supported by sound science.  In re Zoloft Prods. Liab. Litig., No. 12–md–2342, 2015 WL 115486, at * 2 (E.D.Pa. Jan. 7, 2015).

As a result of this ruling, the MDL dragged on for over a year, in which time, the PSC served a report by Jewell, and then the defendants conducted a discovery deposition of Jewell, and lodged a new Rule 702 challenge.  Although Jewell brought more statistical sophistication to the task, he could not transmute lead into gold; nor could he support the plaintiffs’ causal claims without committing most of the same fallacies found in Bérard’s opinions.  After another round of Rule 702 briefs and hearings, the MDL court excluded Jewell’s unwarranted causal opinions. In re Zoloft Prods. Liab. Litig., No. 12–md–2342, 2015 WL 7776911 (E.D.Pa. Dec. 2, 2015).

The successive exclusions of Bérard and Jewell left the MDL court in a peculiar position. There were other witnesses, Robert Cabrera, a teratologist, Michael Levin, a molecular biologist, and Thomas Sadler, an embryologist, whose opinions addressed animal toxicologic studies, biological plausibility, and putative mechanisms.  These other witnesses, however, had little or no competence in epidemiology, and they explicitly relied upon Bérard’s opinions with respect to human outcomes.  As a result of Bérard’s exclusion, these witnesses were left free to offer their views about what happens in animals at high doses, or about theoretical mechanisms, but they were unable to address human causation.

Although the PSC had no expert witnesses who could legitimately offer reasonably supported opinions about the causation of human birth defects, the plaintiffs refused to decamp and leave the MDL forum. Faced with the prospect of not trying their cases to juries, the PSC instead tried the patience of the MDL judge. The PSC pulled out the stops in adducing weak, irrelevant, and invalid evidence to support their claims, sans epidemiologic expertise. The PSC argued that adverse event reports, internal company documents that discussed possible associations, the biological plausibility opinions of Levin and Sadler, the putative mechanism opinions of Cabrera, differential diagnoses offered to support specific causation, and the hip-shot opinions of a former-FDA-commissioner-for-hire, David Kessler could come together magically to supply sufficient evidence to have their cases submitted to juries. Judge Rufe saw through the transparent effort to manufacture evidence of causation, and granted summary judgment on all remaining Zoloft cases in the MDL. s In re Zoloft Prod. Liab. Litig., MDL NO. 2342, 12-MD-2342, 2016 WL 1320799, at *4 (E.D. Pa. April 5, 2016).

After a full briefing and hearing on Bérard’s opinion, a reconsideration of Bérard, a permitted “do over” of general causation with Jewell, a full briefing and hearing on Jewell’s opinions, the MDL court was able to deal deftly with the snippets of evidence “cobbled together” to substitute for evidence that might support a conclusion of causation. The PSC’s cobbled case was puffed up to give the appearance of voluminous evidence, in 200 exhibits that filled six banker’s boxes.  Id. at *5. The ruse was easily undone; most of the exhibits and purported evidence were obvious rubbish. “The quantity of the evidence is not, however, coterminous with the quality of evidence with regard to the issues now before the Court.” Id. The banker’s boxes contained artifices such as untranslated foreign-language documents, and company documents relating to the development and marketing of the medication. The PSC resubmitted reports from Levin, Cabrera, and Sadler, whose opinions were already adjudicated to be incompetent, invalid, irrelevant, or inadequate to support general causation.  The PSC pointed to the specific causation opinions of a clinical cardiologist, Ra-Id Abdulla, M.D., who proffered dubious differential etiologies, ruling in Zoloft as a cause of individual children’s birth defects, despite his inability to rule out truly known and unknown causes in the differential reasoning.  The MDL court, however, recognized that “[a] differential diagnosis assumes that general causation has been established,” id. at *7, and that Abdulla could not bootstrap general causation by purporting to reach a specific causation opinion (even if those specific causation opinions were legitimate).

The PSC submitted the recent consensus statement of the American Statistical Association (ASA)[1], which it misrepresented to be an epidemiologic study.  Id. at *5. The consensus statement makes some pedestrian pronouncements about the difference between statistical and clinical significance, about the need for other considerations in addition to statistical significance, in supporting causal claims, and the lack of bright-line distinctions for statistical significance in assessing causality.  All true, but immaterial to the PSC’s expert witnesses’ opinions that over-endorsed statistical significance in the few instances in which it was shown, and over-interpreted study data that was based upon data mining and multiple comparisons, in blatant violation of the ASA’s declared principles.

Stretching even further for “human evidence,” the PSC submitted documentary evidence of adverse event reports, as though they could support a causal conclusion.[2]  There are about four million live births each year, with an expected rate of serious cardiac malformations of about one per cent.[3]  The prevalence of SSRI anti-depressant use is at least two per cent, which means that we would expect 800 cardiac birth defects each year to occur in children of mother’s who took SSRI anti-depressants in the first trimester. If Zoloft had an average market share of all the SSRIs of about 25 per cent, then 200 cardiac defects each year would occur in children born to mothers who took Zoloft.  Given that Zoloft has been on the market since the early 1990s, we would expect that there would be thousands of children, exposed to Zoloft during embryogenesis, born with cardiac defects, if there was nothing untoward about maternal exposure to the medication.  Add the stimulated reporting of adverse events from lawyers, lawyer advertising, and lawyer instigation, you have manufactured evidence not probative of causation at all.[4] The MDL court cut deftly and swiftly through the smoke screen:

“These reports are certainly relevant to the generation of study hypotheses, but are insufficient to create a material question of fact on general causation.”

Id. at *9. The MDL court recognized that epidemiology was very important in discerning a causal connection between a common exposure and a common outcome, especially when the outcome has an expected rate in the general population. The MDL court stopped short of holding that epidemiologic evidence was required (which on the facts of the case would have been amply justified), but instead supported its ratio decidendi on the need to account for the extant epidemiology that contradicted or failed to support the strident and subjective opinions of the plaintiffs’ expert witnesses. The MDL court thus gave plaintiffs every benefit of the doubt by limiting its holding on the need for epidemiology to:

“when epidemiological studies are equivocal or inconsistent with a causation opinion, experts asserting causation opinions must thoroughly analyze the strengths and weaknesses of the epidemiological research and explain why that body of research does not contradict or undermine their opinion.”

Id. at *5, quoting from In re Zoloft Prods. Liab. Litig., 26 F. Supp. 3d 449, 476 (E.D. Pa. 2014).

The MDL court also saw through the thin veneer of respectability of the testimony of David Kessler, a former FDA commissioner who helped make large fortunes for some of the members of the PSC by the feeding frenzy he created with his moratorium on silicone gel breast implants.  Even viewing Kessler’s proffered testimony in the most charitable light, the court recognized that he offered little support for a causal conclusion other than to delegate the key issues to epidemiologists. Id. at *9. As for the boxes of regulatory documents, foreign labels, and internal company memoranda, the MDL court found that these documents did not raise a genuine issue of material fact concerning general causation:

“Neither these documents, nor draft product documents or foreign product labels containing language that advises use of birth control by a woman taking Zoloft constitute an admission of causation, as opposed to acknowledging a possible association.”

Id.

In the end, the MDL court found that the PSC’s many banker boxes of paper contained too much of nothing for the issue at hand.  Having put the defendants through the time and expense of litigating and re-litigating these issues, nothing short of dismissing the pending cases was a fair and appropriate outcome to the Zoloft MDL.

_______________________________________

Given the denouement of the Zoloft MDL, it is worth considering the MDL judge’s handling of the scientific issues raised, misrepresented, argued, or relied upon by the parties.  Judge Rufe was required, by Rules 702 and 703, to roll up her sleeves and assess the methodological validity of the challenged expert witnesses’ opinions.  That Her Honor was able to do this is a testament to her hard work. Zoloft was not Judge Rufe’s first MDL, and she clearly learned a lot from her previous judicial assignment to an MDL for Avandia personal injury actions.

On May 21, 2007, the New England Journal of Medicine published online a seriously flawed meta-analysis of cardiovascular disease outcomes and rosiglitazone (Avandia) use.  See Steven E. Nissen, M.D., and Kathy Wolski, M.P.H., “Effect of Rosiglitazone on the Risk of Myocardial Infarction and Death from Cardiovascular Causes,” 356 New Engl. J. Med. 2457 (2007).  The Nissen article did not appear in print until June 14, 2007, but the first lawsuits resulted within a day or two of the in-press version. The lawsuits soon thereafter reached a critical mass, with the inevitable creation of a federal court Multi-District Litigation.

Within a few weeks of Nissen’s article, the Annals of Internal Medicine published an editorial by Cynthia Mulrow, and other editors, in which questioned the Nissen meta-analysis[5], and introduced an article that attempted to replicate Nissen’s work[6].  The attempted replication showed that the only way Nissen could have obtained his nominally statistically significant result was to have selected a method, Peto’s fixed effect method, known to be biased for use with clinical trials with uneven arms. Random effect methods, more appropriate for the clinically heterogeneous clinical trials, consistently failed to replicate the Nissen result. Other statisticians weighed in and pointed out that using the risk difference made much more sense when there were multiple trials with zero events in one or the other or both arms of the trials. Trials with zero cardiovascular events in both arms represented important evidence of low, but equal risk, of heart attacks, which should be captured in an appropriate analysis.  When the risk difference approach was used, with exact statistical methods, there was no statistically significant increase in risk in the dataset used by Nissen.[7] Other scientists, including some of Nissen’s own colleagues at the Cleveland Clinic, and John Ioannidis, weighed in to note how fragile and insubstantial the Nissen meta-analysis was[8]:

“As rosiglitazone case demonstrates, minor modifications of the meta-analysis protocol can change the statistical significance of the result.  For small effects, even the direction of the treatment effect estimate may change.”

Nissen achieved his political objective with his shaky meta-analysis.  The FDA convened an Advisory Committee meeting, which in turn resulted in a negative review of the safety data, and the FDA’s imposition of warnings and a Risk Evaluation and Mitigation Strategy, which all but prohibited use of rosiglizone.[9]  A clinical trial, RECORD, had already started, with support from the drug sponsor, GlaxoSmithKline, which fortunately was allowed to continue.

On a parallel track to the regulatory activities, the federal MDL, headed by Judge Rufe, proceeded to motions and a hearing on GSK’s Rule 702 challenge to plaintiffs’ evidence of general causation. The federal MDL trial judge denied GSK’s motions to exclude plaintiffs’ causation witnesses in an opinion that showed significant diffidence in addressing scientific issues.  In re Avandia Marketing, Sales Practices and Product Liability Litigation, 2011 WL 13576, *12 (E.D. Pa. 2011).  See “Learning to Embrace Flawed Evidence – The Avandia MDL’s Daubert Opinion” (Jan. 10, 2011.

After Judge Rufe denied GSK’s challenges to the admissibility of plaintiffs’ expert witnesses’ causation opinions in the Avandia MDL, the RECORD trial was successfully completed and published.[10]  RECORD was a long term, prospectively designed randomized cardiovascular trial in over 4,400 patients, followed on average of 5.5 yrs.  The trial was designed with a non-inferiority end point of ruling out a 20% increased risk when compared with standard-of-care diabetes treatment The trial achieved its end point, with a hazard ratio of 0.99 (95% confidence interval, 0.85-1.16) for cardiovascular hospitalization and death. A readjudication of outcomes by the Duke Clinical Research Institute confirmed the published results.

On Nov. 25, 2013, after convening another Advisory Committee meeting, the FDA announced the removal of most of its restrictions on Avandia:

“Results from [RECORD] showed no elevated risk of heart attack or death in patients being treated with Avandia when compared to standard-of-care diabetes drugs. These data do not confirm the signal of increased risk of heart attacks that was found in a meta-analysis of clinical trials first reported in 2007.”

FDA Press Release, “FDA requires removal of certain restrictions on the diabetes drug Avandia” (Nov. 25, 2013). And in December 2015, the FDA abandoned its requirement of a Risk Evaluation and Mitigation Strategy for Avandia. FDA, “Rosiglitazone-containing Diabetes Medicines: Drug Safety Communication – FDA Eliminates the Risk Evaluation and Mitigation Strategy (REMS)” (Dec. 16, 2015).

GSK’s vindication came too late to reverse Judge Rufe’s decision in the Avandia MDL.  GSK spent over six billion dollars on resolving Avandia claims.  And to add to the company’s chagrin, GSK lost patent protection for Avandia in April 2012.[11]

Something good, however, may have emerged from the Avandia litigation debacle.  Judge Rufe heard from plaintiffs’ expert witnesses in Avandia about the hierarchy of evidence, about how observational studies must be evaluated for bias and confounding, about the importance of statistical significance, and about how studies that lack power to find relevant associations may still yield conclusions with appropriate meta-analysis. Important nuances of meta-analysis methodology may have gotten lost in the kerfuffle, but given that plaintiffs had reasonable quality clinical trial data, Avandia plaintiffs’ counsel could eschew their typical reliance upon weak and irrelevant lines of evidence, based upon case reports, adverse event disproportional reporting, and the like.

The Zoloft litigation introduced Judge Rufe to a more typical pharmaceutical litigation. Because the outcomes of interest were birth defects, there were no clinical trials.  To be sure, there were observational epidemiologic studies, but now the defense expert witnesses were carefully evaluating the studies for bias and confounding, and the plaintiffs’ expert witnesses were double counting studies and ignoring multiple comparisons and validity concerns.  Once again, in the Zoloft MDL, plaintiffs’ expert witnesses made their non-specific complaints about “lack of power” (without ever specifying the relevant alternative hypothesis), but it was the defense expert witnesses who cited relevant meta-analyses that attempted to do something about the supposed lack of power. Plaintiffs’ expert witnesses inconsistently argued “lack of power” to disregard studies that had outcomes that undermined their opinions, even when those studies had narrow confidence intervals surrounding values at or near 1.0.

The Avandia litigation laid the foundation for Judge Rufe’s critical scrutiny by exemplifying the nature and quantum of evidence to support a reasonable scientific conclusion.  Notwithstanding the mistakes made in the Avandia litigation, this earlier MDL created an invidious distinction with the Zoloft PSC’s evidence and arguments, which looked as weak and insubstantial as they really were.

[1] Ronald L. Wasserstein & Nicole A. Lazar, “The ASA’s Statement on p-Values: Context, Process, and Purpose,” The American Statistician, available online (Mar. 7, 2016), in-press at DOI:10.1080/00031305.2016.1154108, <http://dx.doi.org/10.1080/>. See “The American Statistical Association’s Statement on and of Significance” (Mar. 17, 2016); “The ASA’s Statement on Statistical Significance – Buzzing from the Huckabees” (Mar. 19, 2016).

[2] See 21 C.F.R. § 314.80 (a) Postmarketing reporting of adverse drug experiences (defining “[a]dverse drug experience” as “[a]ny adverse event associated with the use of a drug in humans, whether or not considered drug related”).

[3] See Centers for Disease Control and Prevention, “Birth Defects Home Page” (last visited April 8, 2016).

[4] See, e.g., Derrick J. Stobaugh, Parakkal Deepak, & Eli D. Ehrenpreis, “Alleged isotretinoin-associated inflammatory bowel disease: Disproportionate reporting by attorneys to the Food and Drug Administration Adverse Event Reporting System,” 69 J. Am. Acad. Dermatol. 393 (2013) (documenting stimulated reporting from litigation activities).

[5] Cynthia D. Mulrow, John Cornell & A. Russell Localio, “Rosiglitazone: A Thunderstorm from Scarce and Fragile Data,” 147 Ann. Intern. Med. 585 (2007).

[6] George A. Diamond, Leon Bax & Sanjay Kaul, “Uncertain Effects of Rosiglitazone on the Risk for Myocardial Infartion and Cardiovascular Death,” 147 Ann. Intern. Med. 578 (2007).

[7] Tian, et al., “Exact and efficient inference procedure for meta-analysis and its application to the analysis of independent 2 × 2 tables with all available data but without artificial continuity correction” 10 Biostatistics 275 (2008)

[8] Adrian V. Hernandez, Esteban Walker, John P.A. Ioannidis,  and Michael W. Kattan, “Challenges in meta-analysis of randomized clinical trials for rare harmful cardiovascular events: the case of rosiglitazone,” 156 Am. Heart J. 23, 28 (2008).

[9] Janet Woodcock, FDA Decision Memorandum (Sept. 22, 2010).

[10] Philip D. Home, et al., “Rosiglitazone evaluated for cardiovascular outcomes in oral agent combination therapy for type 2 diabetes (RECORD): a multicentre, randomised, open-label trial,” 373 Lancet 2125 (2009).

[11] “Pharmacovigilantism – Avandia Litigation” (Nov. 27, 2013).

Posted in Causation, Expert Witnesses, Meta-analysis, Rule 702, Scientific Evidence, statistical evidence | Comments Off on The Education of Judge Rufe – The Zoloft MDL

Expert Witness – Ghost Busters

March 29th, 2016

Andrew Funkhouser was tried and convicted for selling cocaine.  On appeal, the Missouri Court of Appeals affirmed his conviction and his sentence of prison for 30 years. State v. Funkhouser, 729 S.W.2d 43 (Mo. App. 1987). On a petition for post-conviction relief, Funkhouser asserted that he was deprived of his Sixth Amendment right to effective counsel. Funkhouser v. State, 779 S.W.2d 30 (Mo. App. 1989).

One of the alleged grounds of ineffectiveness was his lawyer’s failure to object to the prosecutor’s cross-examination of a defense expert witness, clinical psychologist Frederick Nolen, on Nolan’s belief in ghosts. Id. at 32. On direct examination, Nolen testified that he had published or presented on multiple personalities, hypnosis, and ghosts.

On cross-examination, the prosecution inquired of Nolan about his theory of ghosts:

“Q. Doctor, I believe that you’ve done some work in the theory of ghosts, is that right?

A. Yes.

Q. I believe you told me that some of that work you’d based on your own experiences, is that correct?

A. Yes.

Q. You also told me you have lived in a haunted house for 13 years, is that right?

A. Yes.

Q. You have seen the ghost, is that correct?

A. Yes.”

Id. at 32-33. Funkhouser asserted that the cross-examination was improper because his expert witness was examined on his religious beliefs, and his counsel was ineffective for failing to object. Id. at 33.  The Missouri Court of Appeals disagreed. Counsel are permitted to cross-examine an adversary’s expert witness

“in any reasonable respect that will test his qualifications, credibility, skill or knowledge and the value and accuracy of his opinions.”

The court held that any failure to object could not be incompetence because the examination was proper. Id.

So there you have it: wacky beliefs systems are fair game for cross-examination of expert witnesses, at least in the “Show-Me” state.

And this broad scope of cross-examination is probably a good thing because almost anything seems to go in Missouri. The Show-Me state has been wiping up the rear in the law of expert witness admissibility. Missouri Revised Statutes contains a version of the Federal Rule of Evidence 702, which goes back to the language before the federal statutory revision in 2000:

Expert witness, opinion testimony admissible–hypothetical question not required, when.

490.065. 1. In any civil action, if scientific, technical or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education may testify thereto in the form of an opinion or otherwise.

In January 2016, the Missouri state senate passed a bill that would bring the Missouri standard in line with the current federal court rule of evidence. Most of the Republican senators voted for the bill; none of the Democrats voted in favor of the reform. Chris Semones, “Missouri: One Step Closer to Daubert,” in Expert Witness Network (Jan. 26, 2016).

Posted in Expert Witnesses, Rule 702, Scientific Evidence | Comments Off on Expert Witness – Ghost Busters

Lipitor MDL Cuts the Fat Out of Specific Causation

March 25th, 2016

Ms. Juanita Hempstead was diagnosed with hyperlipidemia in March 1998. Over a year later, in June 1999, with her blood lipids still elevated, her primary care physician prescribed 20 milligrams of atorvastatin per day. Ms. Hempstead did not start taking the statin regularly until July 2000. In September 2002, her lipids were under control, her blood glucose was abnormally high, and she had gained 13 pounds since she was first prescribed a statin medication. Hempstead v. Pfizer, Inc., 2:14–cv–1879, MDL No. 2:14–mn–02502–RMG, 2015 WL 9165589, at *2-3 (D.S.C. Dec. 11, 2015) (C.M.O. No. 55 in In re Lipitor Marketing, Sales Practices and Products Liability Litigation) [cited as Hempstead]. In the fall of 2003, Hempstead experienced abdominal pain, and she stopped taking the statin for a few weeks, presumably because of a concern over potential liver toxicity. Her cessation of the statin led to an increase in her blood fat, but her blood sugar remained elevated, although not in the range that would have been diagnostic of diabetes. In May 2004, about five years after starting on statin medication, having gained 15 pounds since 1999, Ms. Hempstead was diagnosed with type II diabetes mellitus. Id.

Living in a litigious society, and being bombarded with messages from the litigation industry, Ms. Hempstead sued the manufacturer of atorvastatin, Pfizer, Inc. In support of her litigation claim, Hempstead’s lawyers enlisted the support of Elizabeth Murphy, M.D., D.Phil., a Professor of Clinical Medicine, and Chief of Endocrinology and Metabolism at San Francisco General Hospital. Id. at *6. Dr. Murphy received her doctorate in biochemistry from Oxford University, and her medical degree from the Harvard Medical School. Despite her graduations from elite educational institutions, Dr. Murphy never learned the distinction between ex ante risk and assignment of causality in an individual patient.

Dr. Murphy claimed that atorvastatin causes diabetes, and that the medication caused Ms. Hempstead’s diabetes in 2004. Murphy pointed to a five-part test for her assessment of specific causation:

(1) reports or reliable studies of diabetes in patients taking atorvastatin;

(2) causation is biological plausible;

(3) diabetes appeared in the patient after starting atorvastatin;

(4) the existence of other possible causes of the patient’s diabetes; and

(5) whether the newly diagnosed diabetes was likely caused by the atorvastatin.

Id. In response to this proffered testimony, the defendant, Pfizer, Inc., challenged the admissibility of Dr. Murphy’s opinion under Federal Rule of Evidence 702.

The trial court, in reviewing Pfizer’s challenge, saw that Murphy’s opinion essentially was determined by (1), (2), and (3), above. In other words, once Murphy had become convinced of general causation, she was willing to causally attribute diabetes to atorvastatin in every patient who developed diabetes after starting to take the medication. Id. at *6-7.

Dr. Murphy relied upon some epidemiologic studies that suggested a relative risk of diabetes to be about 1.5 in patients who had taken atorvastatin. Id. at *5, *8. Unfortunately, the trial court, as is all too common among judges writing Rule 702 opinions, failed to provide citations to the materials upon which plaintiff’s expert witness relied. A safe bet, however, is that those studies, if they had any internal and external validity at all, involved multivariate analyses to analyze risk ratios for diabetes at time t1, in patients at time who had no diabetes before starting use of atorvastatin at time t0, compared with patients who did not have diabetes at t0 but never took the statin. If so, then Dr. Murphy’s use of a temporal relationship between starting atorvastatin and developing diabetes is quite irrelevant because the relative risk (1.5) relied upon is generated in studies in which the temporality is present. Ms. Hempstead’s development of diabetes five years after starting atorvastatin does not make her part of a group with a relative risk any higher than the risk ratio of 1.5, cited by Dr. Murphy. Similarly, the absence or presence of putative risk factors other than the accused statin is irrelevant because the risk ratio of 1.5 was mostly likely arrived at in studies that controlled or adjusted for the other risk factors in the epidemiologic study by a multivariate analysis. Id. at *5 & n. 8.

Dr. Murphy acknowledged that there are known risk factors for diabetes, and that plaintiff Ms. Hempstead had a few. Plaintiff was 55 years old at the time of diagnosis, and advancing age is a risk factor. Plaintiff’s body mass index (BMI) was elevated and it had increased over the five years since beginning to take atorvastatin. Even though not obese, Ms. Hempstead’s BMI was sufficiently high to confer a five-fold increase in risk for diabetes. Id. at *9. Plaintiff also had hypertension and metabolic syndrome, both of which are risk factors (with the latter adding to the level of risk of the former). Id. at *10. Perhaps hoping to avoid the intractable problem of identifying which risk factors were actually at work in Ms. Hempstead to produce her diabetes, Dr. Murphy claimed that all risk factors were causes of plaintiff’s diabetes. Her analysis was thus not so much a differential etiology as a non-differential, non-discriminating assertion that any and all risk factors were probably involved in producing the individual case. Not surprisingly, Dr. Murphy, when pressed, could not identify any professional organizations or peer-reviewed publications that employed such a methodology of attribution. Id. at *6. Dr. Murphy had never used such a method of attribution in her clinical practice; instead she attempted to justify and explain her methodology by adverting to its widespread use by expert witnesses in litigation. Id.

Relative Risk and the Inference of Specific Causation

The main thrust of the Dr. Murphy’s and the plaintiff’s specific causation claim seems to have been based upon a simple, simplistic identification of ex ante risk with causation. The MDL court recognized, however, that in science and in law, risk is not the same as causation.[1]

The existence of general causation, with elevated relative risks not likely the result of bias, chance, or confounding, does not necessarily support the inference that every person exposed to the substance or drug and who develops the outcome of interest, had his or her outcome caused by the exposure.

The law requires each plaintiff to show that his or her alleged injury, the outcome in the relied upon epidemiologic studies, was actually caused by the alleged exposure under a preponderance of the evidence. Id. at *4 (citing Guinn v. AstraZeneca Pharm. LP, 602 F.3d 1245, 1249 n. 1 (11th Cir.2010))

The disconnect between risk and causation is especially strong when the nature of the causation involved results from the modification of the incidence rate of a disease as a function of exposure. Although the MDL court did not explicitly note the importance of a base rate, which gives rise to an “expected value” or “expected outcome” in an epidemiologic sample, the court’s insistence upon a relative risk greater than two, from studies of sample groups that are sufficiently similar to the plaintiff, implicitly affirms the principle. The MDL court did, however, call out Dr. Murphy’s reasoning that specific causation exists for every drug-exposed patient, in the face of studies that show general causation with associations of the magnitude less than risk ratios of two, was logically flawed. Id. at *8 (citing Guinn v. AstraZeneca Pharm. LP, 602 F.3d 1245, 1255 (11th Cir. 2010) (“The fact that exposure to [a substance] may be a risk factor for [a disease] does not make it an actual cause simply because [the disease] developed.”).

The MDL court acknowledged the obvious, that some causal relationships may be based upon risk ratios of two or less (but greater than 1.0). Id. at *4. A risk ratio greater than 1.0, but not greater than two, can result only when some of the cases with the outcome of interest, here diabetes, would have occurred anyway in the population that has been sampled. And with increased risk ratios at two or less, a majority of the study sample would have developed the outcome even in the absence of the exposure of interest. With this in mind, the MDL court asked how plaintiff could show specific causation, even assuming that general causation were established with the use of epidemiologic methods.

The court in Hempstead reasoned that if the risk ratio were greater than 2.0, a majority of the exposed sample would have developed the outcome of interest because of the exposure being studied. Id. at *5. If the sampled population has had the same level of exposure as the plaintiff, then a case-specific inference of specific causation is supported.[2] Of course, this inferential strategy presupposes that general causation has been established, by ruling out bias, confounding, and chance, with high-quality, statistically significant findings of risk ratios in excess of 2.0. Id. at *5.

To be sure, there are some statisticians, such as Sander Greenland, who have criticized this use of a sample metric to assess the probability of individual causation, in part because the sample metric is an average level of risk, based upon the whole sample. Greenland is fond of speculating that the risk may not be stochastically distributed, but as the Supreme Court has recently acknowledged, there are times when the use of an average is appropriate to describe individuals within a sampled population. Tyson Foods, Inc. v. Bouaphakeo, No. 14-1146, 2016 WL 1092414 (U.S. S. Ct. Mar. 22, 2016).

The Whole Tsumish

Dr. Murphy, recognizing that there are other known and unknown causes and risk factors for diabetes, made a virtue of foolish consistency by opining that all risk factors present in Ms. Hempstead were involved in producing her diabetes. Dr. Murphy did not, and could not, explain, however, how or why she believed that every risk factor (age, BMI, hypertension, recent weight gain, metabolic syndrome, etc.), rather than some subset of factors, or some idiopathic factors, were involved in producing the specific plaintiff’s disease. The MDL court concluded that Dr. Murphy’s opinion was an ipse dixit of the sort that qualified her opinion for exclusion from trial. Id. at *10.

Biological Fingerprints

Plaintiffs posited typical arguments about “fingerprints” or biological markers that would support inferences of specific causation in the absence of high relative risks, but as is often the case with such arguments, they had no factual foundation for their claims that atorvastatin causes diabetes. Neither Dr. Murphy nor anyone else had ever identified a biological marker that allowed drug-exposed patients with diabetes to be identified as having had their diabetes actually caused by the drug of interest, as opposed to other known or unknown causes.

With Dr. Murphy’s testimony failing to satisfy common sense and Rule 702, plaintiff relied upon cases in which circumstances permitted inferences of specific causation from temporal relationships between exposure and outcome. In one such case, the plaintiff developed throat irritation from very high levels of airborne industrial talc exposure, which abated upon cessation of exposure, and returned with renewed exposure. Given that general causation was conceded, and natural experimental nature of challenge, dechallenge, and rechallenge, the Fourth Circuit in this instance held that the temporal relationship of an acute insult and onset was an adequate basis for expert witness opinion testimony on specific causation. Id. at *11. (citing Westberry v. Gislaved Gummi AB, 178 F.3d 257, 265 (4th Cir.1999) (“depending on the circumstances, a temporal relationship between exposure to a substance and the onset of a disease or a worsening of symptoms can provide compelling evidence of causation”); Cavallo v. Star Enter., 892 F. Supp. 756, 774 (E.D. Va.1995) (discussing unique, acute onset of symptoms caused by chemicals). In the Hempstead case, however, the very nature of the causal relationship claimed did not involve an acute reaction. The claimed injury, diabetes, emerged five years after statin use commenced, and the epidemiologic studies relied upon were all based upon this chronic use, with a non-acute, latent outcome. The trial judge thus would not credit the mere temporality between drug use and new onset of diabetes as probative of anything.

[1] Id. at *8, citing Guinn v. AstraZeneca Pharm. LP, 602 F.3d 1245, 1255 (11th Cir.2010) (“The fact that exposure to [a substance] may be a risk factor for [a disease] does not make it an actual cause simply because [the disease] developed.”); id. at *11, citing McClain v. Metabolife Int’l, Inc., 401 F.3d 1233, 1243 (11th Cir.2005) (“[S]imply because a person takes drugs and then suffers an injury does not show causation. Drawing such a conclusion from temporal relationships leads to the blunder of the post hoc ergo propter hoc fallacy.”); see also Roche v. Lincoln Prop. Co., 278 F.Supp. 2d 744, 752 (E.D. Va.2003) (“Dr. Bernstein’s reliance on temporal causation as the determinative factor in his analysis is suspect because it is well settled that a causation opinion based solely on a temporal relationship is not derived from the scientific method and is therefore insufficient to satisfy the requirements of Rule 702.”) (internal quotes omitted).

[2] See Reference Manual on Scientific Evidence at 612 (3d ed. 2011) (noting “the logic of the effect of doubling of the risk”); see also Marder v.G.D. Searle & Co., 630 F. Supp. 1087, 1092 (D. Md.1986) (“In epidemiological terms, a two-fold increased risk is an important showing for plaintiffs to make because it is the equivalent of the required legal burden of proof-a showing of causation by the preponderance of the evidence or, in other words, a probability of greater than 50%.”).

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The opinions, statements, and asseverations expressed on Tortini are my own, or those of invited guests, and these writings do not necessarily represent the views of clients, friends, or family, even when supported by good and sufficient reason.