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

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

October 21st, 2018

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

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

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

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

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

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

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

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

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

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

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

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

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

A Clear and Present Danger

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

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

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

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

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

Brief at 212.

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

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

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

Authority for Judicial Control

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

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

Brief at 228 (internal citations omitted).

Criteria of Validity

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The Hazard of Composite End Points – More Lumpenepidemiology in the Courts

October 20th, 2018

One of the challenges of epidemiologic research is selecting the right outcome of interest to study. What seems like a simple and obvious choice can often be the most complicated aspect of the design of clinical trials or studies.1 Lurking in this choice of end point is a particular threat to validity in the use of composite end points, when the real outcome of interest is one constituent among multiple end points aggregated into the composite. There may, for instance, be strong evidence in favor of one of the constituents of the composite, but using the composite end point results to support a causal claim for a different constituent begs the question that needs to be answered, whether in science or in law.

The dangers of extrapolating from one disease outcome to another is well-recognized in the medical literature. Remarkably, however, the problem received no meaningful discussion in the Reference Manual on Scientific Evidence (3d ed. 2011). The handbook designed to help judges decide threshold issues of admissibility of expert witness opinion testimony discusses the extrapolation from sample to population, from in vitro to in vivo, from one species to another, from high to low dose, and from long to short duration of exposure. The Manual, however, has no discussion of “lumping,” or on the appropriate (and inappropriate) use of composite or combined end points.

Composite End Points

Composite end points are typically defined, perhaps circularly, as a single group of health outcomes, which group is made up of constituent or single end points. Curtis Meinert defined a composite outcome as “an event that is considered to have occurred if any of several different events or outcomes is observed.”2 Similarly, Montori defined composite end points as “outcomes that capture the number of patients experiencing one or more of several adverse events.”3 Composite end points are also sometimes referred to as combined or aggregate end points.

Many composite end points are clearly defined for a clinical trial, and the component end points are specified. In some instances, the composite nature of an outcome may be subtle or be glossed over by the study’s authors. In the realm of cardiovascular studies, for example, investigators may look at stroke as a single endpoint, without acknowledging that there are important clinical and pathophysiological differences between ischemic strokes and hemorrhagic strokes (intracerebral or subarachnoid). The Fletchers’ textbook4 on clinical epidemiology gives the example:

In a study of cardiovascular disease, for example, the primary outcomes might be the occurrence of either fatal coronary heart disease or non-fatal myocardial infarction. Composite outcomes are often used when the individual elements share a common cause and treatment. Because they comprise more outcome events than the component outcomes alone, they are more likely to show a statistical effect.”

Utility of Composite End Points

The quest for statistical “power” is often cited as a basis for using composite end points. Reduction in the number of “events,” such as myocardial infarction (MI), through improvements in medical care has led to decreased rates of MI in studies and clinical trials. These low event rates have caused power issues for clinical trialists, who have responded by turning to composite end points to capture more events. Composite end points permit smaller sample sizes and shorter follow-up times, without sacrificing power, the ability to detect a statistically significant increased rate of a prespecified size and Type I error. Increasing study power, while reducing sample size or observation time, is perhaps the most frequently cited rationale for using composite end points.

Competing Risks

Another reason sometimes offered in support of using composite end points is composites provide a strategy to avoid the problem of competing risks.5 Death (any cause) is sometimes added to a distinct clinical morbidity because patients who are taken out of the trial by death are “unavailable” to experience the morbidity outcome.

Multiple Testing

By aggregating several individual end points into a single pre-specified outcome, trialists can avoid corrections for multiple testing. Trials that seek data on multiple outcomes, or on multiple subgroups, inevitably raise concerns about the appropriate choice of the measure for the statistical test (alpha) to determine whether to reject the null hypothesis. According to some authors, “[c]omposite endpoints alleviate multiplicity concerns”:

If designated a priori as the primary outcome, the composite obviates the multiple comparisons associated with testing of the separate components. Moreover, composite outcomes usually lead to high event rates thereby increasing power or reducing sample size requirements. Not surprisingly, investigators frequently use composite endpoints.”6

Other authors have similarly acknowledged that the need to avoid false positive results from multiple testing is an important rationale for composite end points:

Because the likelihood of observing a statistically significant result by chance alone increases with the number of tests, it is important to restrict the number of tests undertaken and limit the type 1 error to preserve the overall error rate for the trial.”7

Indecision about an Appropriate Single Outcome

The International Conference on Harmonization suggests that the inability to select a single outcome variable may lead to the adoption of a composite outcome:

If a single primary variable cannot be selected …, another useful strategy is to integrate or combine the multiple measurements into a single or composite variable.”8

The “indecision” rationale has also been criticized as “generally not a good reason to use a composite end point.”9

Validity of Composite End Points

The validity of composite end points depends upon methodological assumptions, which will have to be made at the time of the study design and protocol creation. After the data are collected and analyzed, the assumptions may or may not be supported. Among the supporting assumptions about the validity of using composites are:10

  • similarity in patient importance for included component end points,

  • similarity of association size of the components, and

  • number of events across the components.

The use of composite end points can sometimes be appropriate in the “first look” at a class of diseases or disorders, with the understanding that further research will sort out and refine the associated end point. Research into the causes of human birth defects, for instance, often starts out with a look at “all major malformations,” before focusing in on specific organ and tissue systems. To some extent, the legal system, in its gatekeeping function, has recognized the dangers and invalidity of lumping in the epidemiology of birth defects.11 The Frischhertz decision, for instance, clearly acknowledged that given the clear evidence that different birth defects arise at different times, based upon interference with different embryological processes, “lumping” of end points was methodologically inappropriate. 2012 U.S. Dist. LEXIS 181507, at *8 (citing Chamber v. Exxon Corp., 81 F. Supp. 2d 661 (M.D. La. 2000), aff’d, 247 F.3d 240 (5th Cir. 2001) (unpublished)).

The Chamber decision involved a challenge to the causation opinion of frequent litigation industry witness, Peter Infante,12 who attempted to defend his opinion about benzene and chronic myelogenous leukemia, based upon epidemiology of benzene and acute myelogenous leukemia. Plaintiffs’ witnesses and counsel sought to evade the burden of producing evidence of an AML association by pointing to a study that reported “excess leukemias,” without specifying the relevant type. Chamber, 81 F. Supp. 2d at 664. The trial court, however, perspicaciously recognized the claimants’ failure to identify relevant evidence of the specific association needed to support the causal claim.

The Frischhertz and Chamber cases are hardly unique. Several state and federal courts have concurred in the context of cancer causation claims.13 In the context of birth defects litigation, the Public Affairs Committee of the Teratology Society has weighed in with strong guidance that counsels against extrapolation between different birth defects in litigation:

Determination of a causal relationship between a chemical and an outcome is specific to the outcome at issue. If an expert witness believes that a chemical causes malformation A, this belief is not evidence that the chemical causes malformation B, unless malformation B can be shown to result from malformation A. In the same sense, causation of one kind of reproductive adverse effect, such as infertility or miscarriage, is not proof of causation of a different kind of adverse effect, such as malformation.”14

The threat to validity in attributing a suggested risk for a composite end point to all included component end points is not, unfortunately, recognized by all courts. The trial court, in Ruff v. Ensign-Bickford Industries, Inc.,15 permitted plaintiffs’ expert witness to reanalyze a study by grouping together two previously distinct cancer outcomes to generate a statistically significant result. The result in Ruff is disappointing, but not uncommon. The result is also surprising, considering the guidance provided by the American Law Institute’s Restatement:

Even when satisfactory evidence of general causation exists, such evidence generally supports proof of causation only for a specific disease. The vast majority of toxic agents cause a single disease or a series of biologically-related diseases. (Of course, many different toxic agents may be combined in a single product, such as cigarettes.) When biological-mechanism evidence is available, it may permit an inference that a toxic agent caused a related disease. Otherwise, proof that an agent causes one disease is generally not probative of its capacity to cause other unrelated diseases. Thus, while there is substantial scientific evidence that asbestos causes lung cancer and mesothelioma, whether asbestos causes other cancers would require independent proof. Courts refusing to permit use of scientific studies that support general causation for diseases other than the one from which the plaintiff suffers unless there is evidence showing a common biological mechanism include Christophersen v. Allied-Signal Corp., 939 F.2d 1106, 1115-1116 (5th Cir. 1991) (applying Texas law) (epidemiologic connection between heavy-metal agents and lung cancer cannot be used as evidence that same agents caused colon cancer); Cavallo v. Star Enters., 892 F. Supp. 756 (E.D. Va. 1995), aff’d in part and rev’d in part, 100 F.3d 1150 (4th Cir. 1996); Boyles v. Am. Cyanamid Co., 796 F. Supp. 704 (E.D.N.Y. 1992). In Austin v. Kerr-McGee Ref. Corp., 25 S.W.3d 280, 290 (Tex. Ct. App. 2000), the plaintiff sought to rely on studies showing that benzene caused one type of leukemia to prove that benzene caused a different type of leukemia in her decedent. Quite sensibly, the court insisted that before plaintiff could do so, she would have to submit evidence that both types of leukemia had a common biological mechanism of development.”

Restatement (Third) of Torts § 28 cmt. c, at 406 (2010). Notwithstanding some of the Restatement’s excesses on other issues, the guidance on composites, seems sane and consonant with the scientific literature.

Role of Mechanism in Justifying Composite End Points

A composite end point may make sense when the individual end points are biologically related, and the investigators can reasonably expect that the individual end points would be affected in the same direction, and approximately to the same extent:16

Confidence in a composite end point rests partly on a belief that similar reductions in relative risk apply to all the components. Investigators should therefore construct composite endpoints in which the biology would lead us to expect similar effects across components.”

The important point, missed by some investigators and many courts, is that the assumption of similar “effects” must be tested by examining the individual component end points, and especially the end point that is the harm claimed by plaintiffs in a given case.

Methodological Issues

The acceptability of composite end points is often a delicate balance between the statistical power and efficiency gained and the reliability concerns raised by using the composite. As with any statistical or interpretative tool, the key questions turn on how the tool is used, and for what purpose. The reliability issues raised by the use of composites are likely to be highly contextual.

For instance, there is an important asymmetry between justifying the use of a composite for measuring efficacy and the use of the same composite for safety outcomes. A biological improvement in type 2 diabetes might be expected to lead to a reduction in all the macrovascular complications of that disease, but a medication for type 2 diabetes might have a very specific toxicity or drug interaction, which affects only one constituent end point among all macrovascular complications, such as myocardial infarction. The asymmetry between efficacy and safety outcomes is specifically addressed by cardiovascular epidemiologists in an important methodological paper:17

Varying definitions of composite end points, such as MACE, can lead to substantially different results and conclusions. There, the term MACE, in particular, should not be used, and when composite study end points are desired, researchers should focus separately on safety and effectiveness outcomes, and construct separate composite end points to match these different clinical goals.”

There are many clear, published statements that caution consumers of medical studies against being misled by claims based upon composite end points. Several years ago, for example, the British Medical Journal published a paper with six methodological suggestions for consumers of studies, one of which deals explicitly with composite end points:18

“Guide to avoid being misled by biased presentation and interpretation of data

1. Read only the Methods and Results sections; bypass the Discuss section

2. Read the abstract reported in evidence based secondary publications

3. Beware faulty comparators

4. Beware composite endpoints

5. Beware small treatment effects

6. Beware subgroup analyses”

The paper elaborates on the problems that arise from the use of composite end points:19

Problems in the interpretation of these trials arise when composite end points include component outcomes to which patients attribute very different importance… .”

Problems may also arise when the most important end point occurs infrequently or when the apparent effect on component end points differs.”

When the more important outcomes occur infrequently, clinicians should focus on individual outcomes rather than on composite end points. Under these circumstances, inferences about the end points (which because they occur infrequently will have very wide confidence intervals) will be weak.”

Authors generally acknowledge that “[w]hen large variations exist between components the composite end point should be abandoned.”20

Methodological Issues Concerning Causal Inferences from Composite End Points to Individual End Points

Several authors have criticized pharmaceutical companies for using composite end points to “game” their trials. Composites allow smaller sample size, but they lend themselves to broader claims for outcomes included within the composite. The same criticism applies to attempts to infer that there is risk of an individual endpoint based upon a showing of harm in the composite endpoint.

If a trial report specifies a composite endpoint, the components of the composite should be in the well-known pathophysiology of the disease. The researchers should interpret the composite endpoint in aggregate rather than as showing efficacy of the individual components. However, the components should be specified as secondary outcomes and reported beside the results of the primary analysis.”21

Virtually the entire field of epidemiology and clinical trial study has urged caution in inferring risk for a component end point from suggested risk in a composite end point:

In summary, evaluating trials that use composite outcome requires scrutiny in regard to the underlying reasons for combining endpoints and its implications and has impact on medical decision-making (see below in Sect. 47.8). Composite endpoints are credible only when the components are of similar importance and the relative effects of the intervention are similar across components (Guyatt et al. 2008a).”22

Not only do important methodologists urge caution in the interpretation of composite end points,23 they emphasize a basic point of scientific (and legal) relevancy:

[A] positive result for a composite outcome applies only to the cluster of events included in the composite and not to the individual components.”24

Even regular testifying expert witnesses for the litigation industry insist upon the “principle of full disclosure”:

The analysis of the effect of therapy on the combined end point should be accompanied by a tabulation of the effect of the therapy for each of the component end points.”25

Gatekeepers in our judicial system need to be more vigilant against bait-and-switch inferences based upon composite end points. The quest for statistical power hardly justifies larding up an end point with irrelevant data points.

1 See, e.g., Milton Packer, “Unbelievable! Electrophysiologists Embrace ‘Alternative Facts’,” MedPage (May 16, 2018) (describing clinical trialists’ abandoning pre-specified intention-to-treat analysis).

2 Curtis Meinert, Clinical Trials Dictionary (Johns Hopkins Center for Clinical Trials 1996).

3 Victor M. Montori, et al., “Validity of composite end points in clinical trials.” 300 Brit. Med. J. 594, 596 (2005).

4 R. Fletcher & S. Fletcher, Clinical Epidemiology: The Essentials at 109 (4th ed. 2005).

5 Neaton, et al., “Key issues in end point selection for heart failure trials: composite end points,” 11 J. Cardiac Failure 567, 569a (2005).

6 Schulz & Grimes, “Multiplicity in randomized trials I: endpoints and treatments,” 365 Lancet 1591, 1593a (2005).

7 Freemantle & Calvert, “Composite and surrogate outcomes in randomized controlled trials,” 334 Brit. Med. J. 756, 756a – b (2007).

8 International Conference on Harmonisation of Technical Requrements for Registration of Pharmaceuticals for Human Use; “ICH harmonized tripartite guideline: statistical principles for clinical trials,” 18 Stat. Med. 1905 (1999).

9 Neaton, et al., “Key issues in end point selection for heart failure trials: composite end points,” 11 J. Cardiac Failure 567, 569b (2005).

10 Montori, et al., “Validity of composite end points in clinical trials.” 300 Brit. Med. J. 594, 596, Summary Point No. 2 (2005).

11 SeeLumpenepidemiology” (Dec. 24, 2012), discussing Frischhertz v. SmithKline Beecham Corp., 2012 U.S. Dist. LEXIS 181507 (E.D. La. 2012).Frischhertz was decided in the same month that a New York City trial judge ruled Dr. Shira Kramer out of bounds in the commission of similarly invalid lumping, in Reeps v. BMW of North America, LLC, 2012 NY Slip Op 33030(U), N.Y.S.Ct., Index No. 100725/08 (New York Cty. Dec. 21, 2012) (York, J.), 2012 WL 6729899, aff’d on rearg., 2013 WL 2362566, aff’d, 115 A.D.3d 432, 981 N.Y.S.2d 514 (2013), aff’d sub nom. Sean R. v. BMW of North America, LLC, ___ N.E.3d ___, 2016 WL 527107 (2016). See also New York Breathes Life Into Frye Standard – Reeps v. BMW(Mar. 5, 2013).

12Infante-lizing the IARC” (May 13, 2018).

13 Knight v. Kirby Inland Marine, 363 F.Supp. 2d 859, 864 (N.D. Miss. 2005), aff’d, 482 F.3d 347 (5th Cir. 2007) (excluding opinion of B.S. Levy on Hodgkin’s disease based upon studies of other lymphomas and myelomas); Allen v. Pennsylvania Eng’g Corp., 102 F.3d 194, 198 (5th Cir. 1996) (noting that evidence suggesting a causal connection between ethylene oxide and human lymphatic cancers is not probative of a connection with brain cancer);Current v. Atochem North America, Inc., 2001 WL 36101283, at *3 (W.D. Tex. Nov. 30, 2001) (excluding expert witness opinion of Michael Gochfeld, who asserted that arsenic causes rectal cancer on the basis of studies that show association with lung and bladder cancer; Hill’s consistency factor in causal inference does not apply to cancers generally); Exxon Corp. v. Makofski, 116 S.W.3d 176, 184-85 (Tex. App. Houston 2003) (“While lumping distinct diseases together as ‘leukemia’ may yield a statistical increase as to the whole category, it does so only by ignoring proof that some types of disease have a much greater association with benzene than others.”).

14The Public Affairs Committee of the Teratology Society, “Teratology Society Public Affairs Committee Position Paper Causation in Teratology-Related Litigation,” 73 Birth Defects Research (Part A) 421, 423 (2005).

15 168 F. Supp. 2d 1271, 1284–87 (D. Utah 2001).

16 Montori, et al., “Validity of composite end points in clinical trials.” 300 Brit. Med. J. 594, 595b (2005).

17 Kevin Kip, et al., “The problem with composite end points in cardiovascular studies,” 51 J. Am. Coll. Cardiol. 701, 701 (2008) (Abstract – Conclusions) (emphasis in original).

18 Montori, et al., “Users’ guide to detecting misleading claims in clinical research reports,” 329 Brit. Med. J. 1093 (2004) (emphasis added).

19 Id. at 1094b, 1095a.

20 Montori, et al., “Validity of composite end points in clinical trials.” 300 Brit. Med. J. 594, 596 (2005).

21 Schulz & Grimes, “Multiplicity in randomized trials I: endpoints and treatments,” 365 Lancet 1591, 1595a (2005) (emphasis added). These authors acknowledge that composite end points often lack clinical relevancy, and that the gain in statistical efficiency comes at the high cost of interpretational difficulties. Id. at 1593.

22 Wolfgang Ahrens & Iris Pigeot, eds., Handbook of Epidemiology 1840 (2d ed. 2014) (47.5.8 Use of Composite Endpoints).

23 See, e.g., Stuart J. Pocock, John J.V. McMurray, and Tim J. Collier, “Statistical Controversies in Reporting of Clinical Trials: Part 2 of a 4-Part Series on Statistics for Clinical Trials,” 66 J. Am. Coll. Cardiol. 2648, 2650-51 (2015) (“Interpret composite endpoints carefully.”)(“COMPOSITE ENDPOINTS. These are commonly used in CV RCTs to combine evidence across 2 or more outcomes into a single primary endpoint. But, there is a danger of oversimplifying the evidence by putting too much emphasis on the composite, without adequate inspection of the contribution from each separate component.”); Eric Lim, Adam Brown, Adel Helmy, Shafi Mussa, and Douglas G. Altman, “Composite Outcomes in Cardiovascular Research: A Survey of Randomized Trials,” 149 Ann. Intern. Med. 612, 612, 615-16 (2008) (“Individual outcomes do not contribute equally to composite measures, so the overall estimate of effect for a composite measure cannot be assumed to apply equally to each of its individual outcomes.”) (“Therefore, readers are cautioned against assuming that the overall estimate of effect for the composite outcome can be interpreted to be the same for each individual outcome.”); Freemantle, et al., “Composite outcomes in randomized trials: Greater precision but with greater uncertainty.” 289 J. Am. Med. Ass’n 2554, 2559a (2003) (“To avoid the burying of important components of composite primary outcomes for which on their own no effect is concerned, . . . the components of a composite outcome should always be declared as secondary outcomes, and the results described alongside the result for the composite outcome.”).

24 Freemantle & Calvert, “Composite and surrogate outcomes in randomized controlled trials.” 334 Brit. Med. J. 757a (2007).

25 Lem Moyé, “Statistical Methods for Cardiovascular Researchers,” 118 Circulation Research 439, 451 (2016).

Cartoon Advocacy for Causal Claims

October 5th, 2018

I saw him today at the courthouse
On his table was a sawed-in-half man
He was practiced at the art of deception
Well I could tell by his blood-stained hands
Ah yeah! Yeah1

Mark Lanier’s Deceptive Cartoon Advocacy

A recent book by Kurt Andersen details the extent of American fantasy, in matters religious, political, and scientific.2 Andersen’s book is a good read and a broad-ranging dissection of the American psyche for cadswallop. The book has one gaping hole, however. It completely omits the penchant for fantasy in American courtrooms.

Ideally, the trial lawyers in a case balance each other and their distractions drop out of the judge or jury’s search for the truth. Sometimes, probably too frequently in so-called toxic tort cases, plaintiffs’ counsel’s penchant for fantasy is so great and persistent that it overwhelms the factfinder’s respect for the truth, and results in an unjust award. In a telling article in Forbes, Mr. Daniel Fisher has turned his sights upon plaintiffs’ lawyer Mark Lanier and his role in helping a jury deliver a $5 billion (give or take a few shekels).3

The $5 billion verdict came in the St. Louis, Missouri, courtroom of Judge Rex Burlison, who presided over a multi-plaintiff case in which the plaintiffs claimed that they had developed ovarian cancer from using Johnson & Johnson’s talcum powder. In previous trials, plaintiffs’ counsel and expert witnesses attempted to show that talc itself could cause ovarian cancer, with inconsistent jury results. Mr. Lanier took a different approach in claiming that the talcum powder was contaminated with asbestos, which caused his clients to develop ovarian cancer.

The asserted causal relationship between occupational or personal exposure to talc and ovarian cancer is tenuous at best, but there is at least a debatable issue about the claimed association between occupational asbestos use and ovarian cancer. The more thoughtful reviews of the issue, however, are cautious in noting that disease outcome misclassification (misdiagnosing mesotheliomas that would be expected in these occupational cohorts with ovarian cancer) make conclusions difficult. See, e.g., Alison Reid, Nick de Klerk and Arthur W. (Bill) Musk, “Does Exposure to Asbestos Cause Ovarian Cancer? A Systematic Literature Review and Meta-analysis,” 20 Cancer Epidemiol. Biomarkers & Prevention 1287 (2011).

Fisher reported that Lanier, after obtaining the $5 billion verdict, presented to a litigation industry meeting, held at a plush Napa Valley resort. In this presentation, Lanier described his St. Louis achievement by likening himself to a magician, and explained “how I sawed the man in half.” Of course, if Lanier had sawed the man in half, he would be a murderer, and the principle of charity requires us to believe that he is merely a purveyor of magical thinking, a deceiver, practiced in the art of deception.

Lanier’s boast about his magical skills is telling. The whole point of the magician’s act is to thrill an audience by the seemingly impossible suspension of the laws of nature. Deception, of course, is the key to success for a magician, or an illusionist of any persuasion. It is comforting to think that Lanier regards himself as an illusionist because his self-characterization suggests that he does not really believe in his own courtroom illusions.

Lanier’s magical thinking and acts have gotten him into trouble before. Fisher noted that Lanier had been branded as deceptive by the second highest court in the United States, the United States Court of Appeals, in Christopher v. DePuy Orthopaedics, Inc., Nos. 16-11051, et al., 2018 U.S. App. LEXIS 10476 (5th Cir. April 25, 2018). In Christopher, Lanier had appeared to engineer payments to expert witnesses in a way that he thought he could tell the jury that the witnesses had no pecuniary interest in the case. Id. at *67. The Court noted that “[l]awyers cannot engage with a favorable expert, pay him ‘for his time’, then invite him to testify as a purportedly ‘non-retained’ neutral party. That is deception, plain and simple.” Id. at *67. The Court concluded that “Lanier’s deceptions furnish[ed] independent grounds for a new trial, id. at *8, because Lanier’s “deceptions [had] obviously prevented defendants from ‘fully and fairly’ defending themselves.” Id. at *69.

Cartoon Advocacy

In his presentation to the litigation industry meeting in Napa Valley, Lanier explained that “Every judge lives by certain rules, just like in sports, but every stadium is also allowed to size themselves appropriately to the game.” See Fisher at note 3. Lanier’s magic act thrives in courtrooms where anything goes. And apparently, Lanier was telling his litigation industry audience that anything goes in the St. Louis courtroom of Judge Burlison.

In some of the ovarian cancer cases, Lanier had a problem: the women had a BrCa2 deletion mutation, which put them at a very high lifetime risk of ovarian cancer, irrespective of what exogenous exposures they may have had. Lanier was undaunted by this adverse evidence, and he spun a story that these women were at the edge of a cliff, when evil Johnson & Johnson’s baby powder came along and pushed them over the cliff:

Lanier Exhibit (from Fisher’s article in Forbes)

Whatever this cartoon lacks in artistic ability, we should give the magician his due; this is a powerful rhetorical metaphor, but it is not science. If it were, there would be a study that showed that ovarian cancers occurred more often in women with BrCa 2 mutations and talcum exposure than in women with BrCa 2 mutations without talcum exposure. The cartoon also imputes an intention to harm specific plaintiffs, which is not supported by the evidence. Lanier’s argument about the “edge of the cliff” does not change the scientific or legal standard that the alleged harm be the sine qua non of the tortious exposure. In the language of the American Law Institute’s Restatement of Torts4:

An actor’s tortious conduct must be a factual cause of another’s physical harm for liability to be imposed. Conduct is a factual cause of harm when the harm would not have occurred absent the conduct.”

Lanier’s cartoon also mistakes risk, if risk it should be, with cause in fact. Reverting back to basic principles, Kenneth Rothman reminds us5:

An elementary but essential principle to keep in mind is that a person may be exposed to an agent and then develop disease without there being any causal connection between the exposure and the disease. For this reason, we cannot consider the incidence proportion or the incidence rate among exposed people to measure a causal effect.”

Chain, Chain, Chain — Chain of Foolish Custody

Johnson & Johnson has moved for a new trial, complaining about Lanier’s illusionary antics, as well as cheesy lawyering. Apparently, Lanier used a block of cheese to illustrate his view of talc mining. In most courtrooms, argument is confined to closing statements of counsel, but in Judge Burlison’s courtroom, Lanier seems to have engaged in one, non-stop argument from the opening bell.

Whether there was asbestos in Johnson & Johnson’s baby powder was obviously a key issue in Lanier’s cases. According to Fisher’s article, Lanier was permitted, over defense objections, to present expert witness opinion testimony based upon old baby powder samples bought from collectors on eBay, for which chain of custody was lacking or incomplete. If this reporting is accurate, then Mr. Lanier is truly a magician, with the ability to make well-established law disappear.6

The Lanier Firm’s Website

One suggestion of how out of control Judge Burlison’s courtroom was is evidenced in Johnson & Johnson’s motion for a new trial, as reported by Fisher. Somehow, defense counsel had injected the content of Lanier’s firm’s website into the trial. According to the motion for new trial, that website had stated that talc “used in modern consumer products” was not contaminated with asbestos. In his closing argument, however, Lanier told the jury he had looked at his website, and the alleged admission was not there.

How the defense was permitted to talk about what was on Lanier’s website is a deep jurisprudential puzzle. Such a statement would be hearsay, without an authorizing exception. Perhaps the defense argued that Lanier’s website was the admission by an agent of the plaintiffs, authorized to speak for them. The attorney-client relationship does create an agent-principal relationship, but it is difficult to fathom that it extends to every statement that Mr. Lanier made outside the record of the trials before the court. If you dear reader are aware of authority to the contrary, please let me know.

Whatever tenuous basis the defense may have advanced, in this cartoon trial, to inject Mr. Lanier’s personal extrajudicial statements into evidence, Mr. Lanier went one parsec farther, according to Fisher. In his closing argument, Lanier blatantly testified that he had checked the website cited and that the suggested statement was not there.

Sounds like a cartoon and a circus trial all bound up together; something that would bring smiles to the faces of Penn Jillette, P.T. Barnum, and Donald Duck.

1 With apologies to Mick Jagger and Keith Richards, and their “You Can’t Always Get What You Want,” from which I have borrowed.

2 Kurt Andersen, Fantasyland: How America Went Haywire – A 500-Year History (2017).

4 “Factual Cause,” A.L.I. Restatement of the Law of Torts (Third): Liability for Physical & Emotional Harm § 26 (2010).

5 Kenneth J. Rothman, Epidemiology: An Introduction at 57 (2d ed. 2012).

6 Paul C. Giannelli, “Chain of Custody,” Crim. L. Bull. 446 (1996); R. Thomas Chamberlain, “Chain of Custody: Its Importance and Requirements for Clinical Laboratory Specimens,” 20 Lab. Med. 477 (1989).

Carl Cranor’s Conflicted Jeremiad Against Daubert

September 23rd, 2018

Carl Cranor’s Conflicted Jeremiad Against Daubert

It seems that authors who have the most intense and refractory conflicts of interest (COI) often fail to see their own conflicts and are the most vociferous critics of others for failing to identify COIs. Consider the spectacle of having anti-tobacco activists and tobacco plaintiffs’ expert witnesses assert that the American Law Institute had an ethical problem because Institute members included some tobacco defense lawyers.1 Somehow these authors overlooked their own positional and financial conflicts, as well as the obvious fact that the Institute’s members included some tobacco plaintiffs’ lawyers as well. Still, the complaint was instructive because it typifies the abuse of ethical asymmetrical standards, as well as ethical blindspots.2

Recently, Raymond Richard Neutra, Carl F. Cranor, and David Gee published a paper on the litigation use of Sir Austin Bradford Hill’s considerations for evaluating whether an association is causal or not.3 See Raymond Richard Neutra, Carl F. Cranor, and David Gee, “The Use and Misuse of Bradford Hill in U.S. Tort Law,” 58 Jurimetrics 127 (2018) [cited here as Cranor]. Their paper provides a startling example of hypocritical and asymmetrical assertions of conflicts of interests.

Neutra is a self-styled public health advocate4 and the Chief of the Division of Environmental and Occupational Disease Control (DEODC) of the California Department of Health Services (CDHS). David Gee, not to be confused with the English artist or the Australian coin forger, is with the European Environment Agency, in Copenhagen, Denmark. He is perhaps best known for his precautionary principle advocacy and his work with trade unions.5

Carl Cranor is with the Center for Progressive Reform, and he teaches philosophy at one of the University of California campuses. Although he is neither a lawyer nor a scientist, he participates with some frequency as a consultant, and as an expert witness, in lawsuits, on behalf of claimants. Perhaps Cranor’s most notorious appearance as an expert witness resulted in the decision of Milward v. Acuity Specialty Products Group, Inc., 639 F.3d 11 (1st Cir. 2011), cert. denied sub nom., U.S. Steel Corp. v. Milward, 132 S. Ct. 1002 (2012). Probably less generally known is that Cranor was one of the founders of an organization, the Council for Education and Research on Toxics (CERT), which recently was the complaining party in a California case in which CERT sought money damages for Starbucks’ failure to label each cup of coffee sold as known to the State of California as causing cancer.6 Having a so-called not-for-profit corporation can also be pretty handy, especially when it holds itself out as a scientific organization and files amicus briefs in support of reversing Daubert exclusions of the founding members of the corporation, as CERT did on behalf of its founding member in the Milward case.7 The conflict of interest, in such an amicus brief, however, is no longer potential or subtle, and violates the duty of candor to the court.

In this recent article on Hill’s considerations for judging causality, Cranor followed CERT’s lead from Milward. Cranor failed to disclose that he has been a party expert witness for plaintiffs, in cases in which he was advocating many of the same positions put forward in the Jurimetrics article, including the Milward case, in which he was excluded from testifying by the trial court. Cranor’s lack of candor with the readers of the Jurimetrics article is all the more remarkable in that Cranor and his co-authors give conflicts of interest outsize importance in substantive interpretations of scholarship:

the desired reliability for evidence evaluation requires that biases that derive from the financial interests and ideological commitments of the investigators and editors that control the gateways to publication be considered in a way that Hill did not address.”

Cranor at 137 & n.59. Well, we could add that Cranor’s financial interests and ideological commitments might well be considered in evaluating the reliability of the opinions and positions advanced in this most recent work by Cranor and colleagues. If you believe that COIs disqualify a speaker from addressing important issues, then you have all the reason you need to avoid reading Cranor’s recent article.

Dubious Scholarship

The more serious problem with Cranor’s article is not his ethically strained pronouncements about financial interests, but the dubious scholarship he and his colleagues advance to thwart judicial gatekeeping of even more dubious expert witness opinion testimony. To begin with, the authors disparage the training and abilities of federal judges to assess the epistemic warrant and reliability of proffered causation opinions:

With their enhanced duties to review scientific and technical testimony federal judges, typically not well prepared by legal education for these tasks, have struggled to assess the scientific support for—and the reliability and relevance of—expert testimony.”

Cranor at 147. Their assessment is fair but hides the authors’ cynical agenda to remove gatekeeping and leave the assessment to lay juries, who are less well prepared for the task, and whose function ensures no institutional accountability, review, or public evaluation.

Similarly, the authors note the temporal context and limitations of Bradford Hill’s 1965 paper, which date and limit the advice provided over 50 years ago in a discipline that has changed dramatically with the advancement of biological, epidemiologic, and genetic science.8 Even at the time of its original publication in 1965, Bradford Hill’s paper, which was based upon an informal lecture, was not designed or intended to be a definitive treatment of causal inference. Cranor and his colleagues make no effort to review Bradford Hill’s many other publications, both before and after his 1965 dinner speech, for evidence of his views on the factors for causal inference, including the role of statistical testing and inference.

Nonetheless, Bradford Hill’s 1965 paper has become a landmark, even if dated, because of its author’s iconic status in the world of public health, earned for his showing that tobacco smoking causes lung cancer,9 and for advancing the role of double-blind randomized clinical trials.10 Cranor and his colleagues made no serious effort to engage with the large body of Bradford Hill’s writings, including his immensely important textbook, The Principles of Medical Statistics, which started as a series of articles in The Lancet, and went through 12 editions in print.11 Hill’s reputation will no doubt survive Cranor’s bowdlerized version of Sir Austin’s views.

Epidemiology is Dispensable When It Fails to Support Causal Claims

The egregious aspect of Cranor’s article is its bill of particulars against the federal judiciary for allegedly errant gatekeeping, which for these authors translates really into any gatekeeping at all. Cranor at 144-45. Indeed, the authors provide not a single example of what was a “proper” exclusion of an expert witness, who was contending for some doubtful causal claim. Perhaps they have never seen a proper exclusion, but doesn’t that speak volumes about their agenda and their biases?

High on the authors’ list of claimed gatekeeping errors is the requirement that a causal claim be supported with epidemiologic evidence. Although some causal claims may be supported by strong evidence of a biological process with mechanistic evidence, such claims are not common in United States tort litigation.

In support of the claim that epidemiology is dispensable, Cranor suggests that:

Some courts have recognized this, and distinguished scientific committees often do not require epidemiological studies to infer harm to humans. For example, the International Agency for Research on Cancer (IRAC) [sic], the National Toxicology Program, and California’s Proposition 65 Scientific Advisory Panel, among others, do not require epidemiological data to support findings that a substance is a probable or—in some cases—a known human carcinogen, but it is welcomed if available.”

Cranor at 149. California’s Proposition 65!??? Even IARC is hard to take seriously these days with its capture by consultants for the litigation industry, but if we were to accept IARC as an honest broker of causal inferences, what substance “known” to IARC to cause cancer in humans (Category I) was branded as a “known carcinogen” without the support of epidemiologic studies? Inquiring minds might want to know, but they will not learn the answer from Cranor and his co-authors.

When it comes to adverting to legal decisions that supposedly support the authors’ claim that epidemiology is unnecessary, their scholarship is equally wanting. The paper cites the notorious Wells case, which was so roundly condemned in scientific circles, that it probably helped ensure that a decision such as Daubert would ultimately be handed down by the Supreme Court. The authors seemingly cannot read, understand, and interpret even the most straightforward legal decisions. Here is how they cite Wells as support for their views:

Wells v. Ortho Pharm. Corp., 788 F.2d 741, 745 (11th Cir. 1986) (reviewing a district court’s decision deciding not to require the use of epidemiological evidence and instead allowing expert testimony).”

Cranor at 149-50 n.122. The trial judge in Wells never made such a decision; indeed, the case was tried by the bench, before the Supreme Court decided Daubert. There was no gatekeeping involved at all. More important, however, and contrary to Cranor’s explanatory parenthetical, both sides presented epidemiologic evidence in support of their positions.12

Cranor and his co-authors similarly misread and misrepresent the trial court’s decision in the litigation over maternal sertraline use and infant birth defects. Twice they cite the Multi-District Litigation trial court’s decision that excluded plaintiffs’ expert witnesses:

In re Zoloft (Sertraline Hydrochloride) Prods. Liab. Litig., 26 F. Supp. 3d 449, 455 (E.D. Pa. 2014) (expert may not rely on nonstatistically significant studies to which to apply the [Bradford Hill] factors).”

Cranor at 144 n.85; 158 n.179. The MDL judge, Judge Rufe, decidedly never held that an expert witness may not rely upon a statistically non-significant study in a “Bradford Hill” analysis, and the Third Circuit, which affirmed the exclusions of the plaintiffs’ expert witnesses’ testimony, was equally clear in avoiding the making of such a pronouncement.13

Who Needs Statistical Significance

Part of Cranor’s post-science agenda is to intimidate judges into believing that statistical significance is unnecessary and a wrong-headed criterion for judging the validity of relied upon research. In their article, Cranor and friends suggest that Hill agreed with their radical approach, but nothing could be further from the truth. Although these authors parse almost every word of Hill’s 1965 article, they conveniently omit Hill’s views about the necessary predicates for applying his nine considerations for causal inference:

Disregarding then any such problem in semantics we have this situation. Our observations reveal an association between two variables, perfectly clear-cut and beyond what we would care to attribute to the play of chance. What aspects of that association should we especially consider before deciding that the most likely interpretation of it is causation?”

Austin Bradford Hill, “The Environment and Disease: Association or Causation?” 58 Proc. Royal Soc’y Med. 295, 295 (1965). Cranor’s radicalism leaves no room for assessing whether a putative association is “beyond what we would care to attribute to the play of chance,” and his poor scholarship ignores Hill’s insistence that this statistical analysis be carried out.14

Hill’s work certainly acknowledged the limitations of statistical method, which could not compensate for poorly designed research:

It is a serious mistake to rely upon the statistical method to eliminate disturbing factors at the completion of the work.  No statistical method can compensate for a badly planned experiment.”

Austin Bradford Hill, Principles of Medical Statistics at 4 (4th ed. 1948). Hill was equally clear, however, that the limits on statistical methods did not imply that statistical methods are not needed to interpret a properly planned experiment or study. In the summary section of his textbook’s first chapter, Hill removed any doubt about his view of the importance, and the necessity, of statistical methods:

The statistical method is required in the interpretation of figures which are at the mercy of numerous influences, and its object is to determine whether individual influences can be isolated and their effects measured.”

Id. at 10 (emphasis added).

In his efforts to eliminate judicial gatekeeping of expert witness testimony, Cranor has struggled with understanding of statistical inference and testing.15 In an early writing, a 1993 book, Cranor suggests that we “can think of type I and II error rates as “standards of proof,” which begs the question whether they are appropriately used to assess significance or posterior probabilities.16 Indeed, Cranor goes further, in confusing significance and posterior probabilities, when he described the usual level of alpha (5%) as the “95%” rule, and claimed that regulatory agencies require something akin to proof “beyond a reasonable doubt,” when they require two “statistically significant” studies.17

Cranor has persisted in this fallacious analysis in his writings. In a 2006 book, he erroneously equated the 95% coefficient of statistical confidence with 95% certainty of knowledge.18 Later in this same text, Cranor again asserted his nonsense that agency regulations are written when supported by “beyond a reasonable doubt.”19 Given that Cranor has consistently confused significance and posterior probability, he really should not be giving advice to anyone about statistical or scientific inference. Cranor’s persistent misunderstandings of basic statistical concepts do, however, explain his motivation for advocating the elimination of statistical significance testing, even if these misunderstandings make his enterprise intellectually unacceptable.

Cranor and company fall into a similar muddle when they offer advice on post-hoc power calculations, which advice ignores standard statistical learning for interpreting completed studies.20 Another measure of the authors’ failed scholarship is their omission of any discussion of recent efforts by many in the scientific community to lower the threshold for statistical significance, based upon the belief that the customary 5% p-value is an order of magnitude too high.21


Relative Risks Greater Than Two

There are other tendentious arguments and treatments in Cranor’s brief against gatekeeping, but I will stop with one last example. The inference of specific causation from study risk ratios has provoked a torrent of verbiage from Sander Greenland (who is cited copiously by Cranor). Cranor, however, does not even scratch the surface of the issue and fails to cite the work of epidemiologists, such as Duncan C. Thomas, who have defended the use of probabilities of (specific) causation. More important, however, Cranor fails to speak out against the abuse of using any relative risk greater than 1.0 to support an inference of specific causation, when the nature of the causal relationship is neither necessary nor sufficient. In this context, Kenneth Rothman has reminded us that someone can be exposed to, or have, a risk, and then develop the related outcome, without there being any specific causation:

An elementary but essential principle to keep in mind is that a person may be exposed to an agent and then develop disease without there being any causal connection between the exposure and the disease. For this reason, we cannot consider the incidence proportion or the incidence rate among exposed people to measure a causal effect.”

Kenneth J. Rothman, Epidemiology: An Introduction at 57 (2d ed. 2012).

The danger in Cranor’s article in Jurimetrics is that some readers will not realize the extreme partisanship in its ipse dixit, and erroneous, pronouncements. Caveat lector

1 Elizabeth Laposata, Richard Barnes & Stanton Glantz, “Tobacco Industry Influence on the American Law Institute’s Restatements of Torts and Implications for Its Conflict of Interest Policies,” 98 Iowa L. Rev. 1 (2012).

2 The American Law Institute responded briefly. See Roberta Cooper Ramo & Lance Liebman, “The ALI’s Response to the Center for Tobacco Control Research & Education,” 98 Iowa L. Rev. Bull. 1 (2013), and the original authors’ self-serving last word. Elizabeth Laposata, Richard Barnes & Stanton Glantz, “The ALI Needs to Implement Modern Conflict of Interest Policies,” 98 Iowa L. Rev. Bull. 17 (2013).

3 Austin Bradford Hill, “The Environment and Disease: Association or Causation?” 58 Proc. Royal Soc’y Med. 295 (1965).

4 Raymond Richard Neutra, “Epidemiology Differs from Public Health Practice,” 7 Epidemiology 559 (1996).

7From Here to CERT-ainty” (June 28, 2018).

8 Kristen Fedak, Autumn Bernal, Zachary Capshaw, and Sherilyn A Gross, “Applying the Bradford Hill Criteria in the 21st Century: How Data Integration Has Changed Causal Inference in Molecular Epidemiology,” Emerging Themes in Epidemiol. 12:14 (2015); John P. A. Ioannides, “Exposure Wide Epidemiology, Revisiting Bradford Hill,” 35 Stats. Med. 1749 (2016).

9 Richard Doll & Austin Bradford Hill, “Smoking and Carcinoma of the Lung,” 2(4682) Brit. Med. J. (1950).

10 Geoffrey Marshall (chairman), “Streptomycin Treatment of Pulmonary Tuberculosis: A Medical Research Council Investigation,” 2 Brit. Med. J. 769, 769–71 (1948).

11 Vern Farewell & Anthony Johnson,The origins of Austin Bradford Hill’s classic textbook of medical statistics,” 105 J. Royal Soc’y Med. 483 (2012). See also Hilary E. Tillett, “Bradford Hill’s Principles of Medical Statistics,” 108 Epidemiol. Infect. 559 (1992).

13 In re Zoloft Prod. Liab. Litig., No. 16-2247 , __ F.3d __, 2017 WL 2385279, 2017 U.S. App. LEXIS 9832 (3d Cir. June 2, 2017) (affirming exclusion of biostatistician Nichols Jewell’s dodgy opinions, which involved multiple methodological flaws and failures to follow any methodology faithfully).

14 See Bradford Hill on Statistical Methods” (Sept. 24, 2013).

16 Carl F. Cranor, Regulating Toxic Substances: A Philosophy of Science and the Law at 33-34 (1993) (arguing incorrectly that one can think of α, β (the chances of type I and type II errors, respectively and 1- β as measures of the “risk of error” or “standards of proof.”); see also id. at 44, 47, 55, 72-76. At least one astute reviewer called Cranor on his statistical solecisms. Michael D. Green, “Science Is to Law as the Burden of Proof is to Significance Testing: Book Review of Cranor, Regulating Toxic Substances: A Philosophy of Science and the Law,” 37 Jurimetrics J. 205 (1997) (taking Cranor to task for confusing significance and posterior (burden of proof) probabilities).

17 Id. (squaring 0.05 to arrive at “the chances of two such rare events occurring” as 0.0025, which impermissibly assumes independence between the two studies).

18 Carl F. Cranor, Toxic Torts: Science, Law, and the Possibility of Justice 100 (2006) (incorrectly asserting that “[t]he practice of setting α =.05 I call the “95% rule,” for researchers want to be 95% certain that when knowledge is gained [a study shows new results] and the null hypothesis is rejected, it is correctly rejected.”).

19 Id. at 266.

21 See, e.g., John P. A. Ioannidis, “The Proposal to Lower P Value Thresholds to .005,” 319 J. Am. Med. Ass’n 1429 (2018); Daniel J. Benjamin, James O. Berger, Valen E. Johnson, et al., “Redefine statistical significance,” 2 Nature Human Behavior 6 (2018).