Trial Magazine

The U.S. Supreme Court’s 1993 decision in Daubert v. Merrell Dow Pharmaceuticals, Inc., was initially hailed as a victory for the admissibility of scientific evidence.¹ Valid but new science regarding various toxic torts would now see the light of day in courtrooms and would no longer be barred for failing to pass the onerous bright-line test of “general acceptance” in the relevant scientific community under Frye v. United States.² The essential holding of Daubert was simply that the Federal Rules of Evidence control, not the general acceptance standard.³ But almost immediately, defense lawyers began asking every expert the same series of questions based on Justice John Paul Stevens’s dicta recommendations in Daubert:

• whether the theory or technique in question can be and has been tested
• whether it has been subjected to peer review and publication
• its known or potential error rate
• the existence and maintenance of standards controlling its operation
• whether it has attracted widespread acceptance within a relevant scientific community.⁴

In relying on these dicta recommendations, the defense has turned Daubert into a far more potent weapon than Frye’s bright-line general acceptance test ever was. This gives the defense the upper hand in terms of greatly increased expense, time, and distraction. But you can still protect—or “Daubert-proof”—your experts in toxic tort cases if you follow some practical steps.

Accurately Framing the Standard

First, in a Daubert hearing, your target audience is the judge, who is usually a lay person on the science. Judges serve as limited gatekeepers, and you must communicate to them the basic fundamentals of the methods and foundation your experts relied on. Give judges the perspective and information they need to allow jurors to hear your evidence.

Focus the judge on the correct burden and goal: Daubert is about proper methodology and data, not the ultimate conclusions.⁵ The proper question is not whether the right conclusion was reached but how the conclusion was reached. Remind the judge that the defense’s misguided attacks on the plaintiff’s science go to weight, not admissibility.⁶

Plaintiff lawyers may be tempted to improperly focus on the ultimate opinion when the overall evidence is extremely convincing. For example, mesothelioma is generally considered a “signature disease” for asbestos exposure. But sometimes the defense denies even this generally accepted conclusion with an onslaught of half-truths. If you make the debate about the ultimate conclusion, it needlessly increases the burden of proof and opens the expert and evidence up to additional layers of attack. Instead, focus on the issues at hand—the methodology and the data. It greatly reduces the range and number of potential spurious attacks.

Perhaps even more dangerous is framing the entire plaintiff response around the shotgun blast of attacks and misrepresentations the defense has made. Although rebutting defense arguments is important, don’t risk improperly framing your case for the judge. The defendant will portray the plaintiff’s science as fundamentally flawed, and you, as the plaintiff lawyer, must avoid desperately plugging holes in a bursting dam.

Rather, redefine the issue presented from the disparate attacks made by the defense. Show the judge that a proper methodology was followed to reach the scientific conclusions you are asserting and that appropriate, reliable data was used. For example, to establish general causation—that a given substance can cause the disease in question—experts may note the key Bradford Hill “viewpoints,” discussed later, and how they apply these to the exposures and harms in the case.⁷

Reframing Mischaracterizations

While the holding of Daubert is that the bright-line test of general acceptance for admissibility of scientific evidence in Frye was too strict,⁸ defendants have argued that under Daubert, multiple barriers or factors must each be satisfied before expert testimony is admissible. To overcome these hurdles, try reframing defense arguments.

Rate of error. The defense often argues that each expert must satisfy the “rate of error” analysis. Daubert does not contain a definition for rate of error, but the National Research Council has offered this commonsense explanation: “‘Error rates’ are defined as proportions of cases in which the analysis led to a false conclusion.”⁹ However, many respected fields of study do not use these types of statistical analyses. Historians often are used in toxic torts to establish “state of the art”—what was knowable at a given point in time. Although historian experts have been attacked with these statistical claims, “historians might not be able to offer an error rate for their opinion, but certainly historians test their theories, publish their research in peer reviewed journals and reach general agreement about certain findings. Moreover, although historians do not quantify confidence levels by articulating error rates, the concept of confidence is not alien to the historian’s job.”¹⁰

Repeatability. Another defense argument centers on the “testability” or “repeatability” of the scientific study or proposition. This is the type of scientific methodology many of us may remember from high school chemistry classes: In the context of experimental science, one can reasonably expect that the results of an experiment are testable and repeatable. For example, if mixing bleach and ammonia together produces a toxic gas in one experiment, it should do the same in the next.

But in most toxic tort situations, the human-based, scientific evidence is typically observational: A group of people were exposed to harmful materials, and after 30 or more years, we begin to see increased cancer rates in that group.¹¹ It would not only be unethical to attempt to reproduce that situation but also impossible. You would need too many people, unethically exposed to a suspect substance, and you would have to carefully follow the cohort for the decades-long latency period. The defense’s bright-line rules do not work in the real world practice of science or have a valid place in a Daubert analysis.¹²

The First Circuit’s decision and analysis in Milward v. Acuity Specialty Products Group, Inc. is a particularly useful guide for distinguishing truly scientific reasoning and analysis from the ‘‘sounds like science’’ rules defense counsel and their experts propose.¹³ Although Milward involves benzene, the discussion of weight of evidence, the various types of valuable scientific data, and the uses and limits of epidemiology are useful for any toxic tort.

Working With Experts

A front-line Daubert tool for plaintiffs is the strategic use of expert disclosures and reports. Your pleadings should frame and explain the proper methodology and data typically relied on in the relevant field—and how your expert applied that accepted methodology and data in the case at hand. Your experts should establish this foundation before proffering detailed opinions and do so with an eye toward protecting themselves from the expected defense attacks at a Daubert hearing.

Early in the process, educate your experts on any medico-legal issues that fall outside of scientific experts’ typical knowledge, such as how a given jurisdiction requires and defines causation, “substantial factor,” or “sufficient to cause.”  For example, even among states that have adopted The Restatement (Second) of Torts, there are widely differing ways of defining “substantial factor”—some lean toward the basic comments provided in the restatement, while others demand that some form of the “frequency, regularity and proximity” test (the Lohrmann standard) be satisfied.¹⁴ Use cases and jury charges so that experts understand how their testimony will be evaluated, how it fits into the case, and how the approach may differ from one jurisdiction to another. 

Discovery depositions of plaintiff experts often are a missed opportunity to educate the judge on the basic methodology and data the expert used. Your experts should be prepared to discuss their methodology and data during the defense’s initial questioning. Also consider conducting a short direct examination focusing on the Daubert issues expected in the case. This will ensure that such evidence does not have to be adduced after the fact through an expert affidavit in response to a Daubert motion. Ask the expert:

• What are your qualifications?
• What methodology and data are generally used by experts in your field?
• How did you learn this methodology?
• Did you use that same methodology in this case and if so, how?
• What case-specific data or hypotheticals are you using to form your opinions in this case?

If the expert’s testimony is essential to your case and you expect a vigorous challenge, view the discovery deposition as a “firewall.” Bring important foundational materials for the expert’s methodology and opinion to the deposition. Using these materials, have your expert explain how applying this methodology led to his or her ultimate opinion. Having such foundational testimony in the record before any Daubert challenges are filed is enormously helpful. It also can force the defense to play its hand on the specific upcoming challenges through attempted cross of your expert at the deposition.

When your experts are challenged, inform them, and provide them with a copy of the Daubert motion. If done properly, the deposition and existing record may be all you need to survive a Daubert challenge. Even if supplementation via affidavit or testimony is necessary, the judge will know that the expert was concerned about using proper scientific procedures from the beginning.

Focus on the Methodology

In the disclosures, reports, and depositions, provide authoritative references for the discipline’s methodology.

Bradford Hill viewpoints. For toxic exposure evidence, the Bradford Hill “considerations” often form the basis for a sound scientific methodology.¹⁵ Rather than requirements, these nine viewpoints might be useful when examining potential cause and effect relationships.¹⁶ As Hill stated: “What they can do, with greater or less strength, is to help us to make up our minds on the fundamental question—is there any other way of explaining the set of facts before us, is there any other answer equally, or more, likely than cause and effect?”¹⁷

Hill intended his considerations to be relevant but not mandatory for determining whether a substance is causing harm. Hill suggested that existing scientific literature may already provide many answers.¹⁸ And just as defense lawyers will falsely argue that all of the Daubert factors must be satisfied, that pattern of misrepresentation often continues with the Bradford Hill viewpoints. However, Hill himself said, “What I do not believe . . . is that we can lay down some hard and fast rules of evidence that must be obeyed before we accept cause and effect. None of my nine viewpoints can bring indisputable evidence for or against the cause-and-effect hypothesis, and none can be required as a sine quo non.”¹⁹

IARC monographs. You also may need to look to extensions of the Bradford Hill viewpoints, such as the preamble to the International Agency for Research on Cancer’s (IARC) monographs.²⁰ IARC’s multivariant methodology includes analyses of all major evidence types, including cell studies, animal studies, exposure studies, case reports, and all forms of available epidemiology in an unbiased interdisciplinary and cooperative process.²¹ Even for use in noncancer toxic torts, IARC’s rejection of the “epidemiology-only” approach and endorsement of a broader “weight of the overall evidence” causation methodology should not be underestimated.

Reference Manual on Scientific Evidence. The Federal Judicial Center’s Reference Manual on Scientific Evidence is another key resource for lawyers and experts on Daubert issues.²² Originally published in 1994 to assist judges after the Daubert decision, this manual is distributed to all federal judges, and both the legal and academic communities have relied on it.²³ This manual is in the chambers of almost every federal judge, so consult and cite to it when writing expert disclosures or preparing experts for their reports and depositions.²⁴ It contains useful observations from scientific literature that can undermine spurious defense attacks. It also contains representations of how scientists work in the field and what data is available to them.

For example, one common defense attack is that the toxic tort plaintiff must know the precise dose of the agent he or she was exposed to and be able to compare that level to precise doses experienced by groups of people manifesting the disease in published studies. The manual explains the practical impossibility of such a position: “Human exposure occurs most frequently in occupational settings where workers are exposed to industrial chemicals such as lead or asbestos; however, even under these circumstances, it is usually difficult, if not impossible, to quantify the amount of exposure.”²⁵

Overcoming Defenses With a Good Offense

Plaintiff lawyers must be ready to go on the offensive. Marshal scientific authorities to support your experts’ evidence and to undermine defense Daubert challenges.

Keep key authoritative articles front and center in the judge’s mind to make the essential points quickly. For example, even though some jurisdictions accept it, the use of “doubling of the risk” (that the risk of harm to the exposed population must be twice that of the unexposed population) as a measure of statistical significance has never been accepted in the scientific community.²⁶ Remind judges that requiring such a test is not the use of “scientific knowledge” as contemplated in Daubert.²⁷

A common industry tactic for attacking even generally accepted science on risk or causation is to sponsor and publish a “re-analysis” of the existing science. This approach makes for a fast and inexpensive publication that often turns the conclusion of the original work on its head. Meta-analysis of multiple studies, although a useful statistical technique when properly executed with sufficiently similar studies, is one type of formal re-analysis defendants often use to dispute the existing scientific consensus or to reach conclusions not justified by the existing original research.

For example, the defense expert’s study will sometimes combine a group of smaller studies that were not designed to answer the essential question—these studies then lack the power to detect an increase in risk, lack the needed latency to find the disease in question, and, perhaps most important, lack consistent and compatible exposure data. The underlying observational studies are usually so dissimilar from one another that the meta-analysis often becomes an obfuscating exercise of adding apples to oranges.²⁸

Use scientific articles to concisely convey to the judge mainstream scientists’ attitude toward the misuse of meta-analysis.²⁹ These articles can serve as a road map to undermine the defense’s Daubert challenge—but keep the focus on key concepts and a few key articles instead of overwhelming the judge and jurors with studies.

Make judges aware of “false balance”—giving both sides “fair” coverage that results in putting discredited pseudoscience on equal footing with legitimate science. Climate change and creation science are prime examples in popular media. Common outlier litigation defense arguments include: There are safe levels of exposure to genotoxic carcinogens; only dose matters and not individual susceptibility; and generally accepted carcinogens do not cause cancer. 

“Doubt science” boutiques use scientific-sounding methods to produce studies that are sold to industry as liability defense and for avoiding regulatory requirements.³⁰ Judges need to be made aware that this problem goes beyond well-paid experts testifying on both sides—doubt science has become a huge industry with its own well-financed experts and journals.³¹ A main goal of this movement is to generate published articles that cast doubt, causing judges to strike your experts and evidence.³²

One doubt science article may reference many others to cloak them all as widely read and reliable papers. According to two cancer epidemiologists:

Product defense studies differ from other research because of the systematic and intentional introduction of bias in their design and/or lack of impartiality in the interpretation of findings: the harmlessness of any agent under investigation is claimed by raising doubts as well as shaping and skewing the scientific literature, manufacturing and magnifying the unavoidable residual scientific uncertainty.³³

Use scientific articles, books, and media articles, as well as skillfully executed discovery, to show judges that the results of industry-funded studies are both predetermined and designed to confuse. For example, after industry scientists published a distortion of the conclusions of a study, the study’s two scientists wrote a letter to the editor clarifying their work and rebuking the authors’ re-analysis.

Such a published letter could be devastating to the use of the re-analysis by the defense. As one such letter notes, “the public health and environmental literature are increasingly inundated with publications whose major purpose is to create doubt and uncertainty in an effort to oppose regulations or support tort litigation.”³⁴ Educate the judge that rather than using science to uncover truths, proponents of doubt science are misleading courts and poisoning scientific literature and scientific methodology.

Defense experts generally will deny knowing anything about bias or scandals, even when it is widely known and disseminated in both scientific and popular media. Counter these denials by introducing published information about doubt science as exhibits in defense expert depositions. This tactic prevents defense experts from playing the “see no evil, hear no evil, speak no evil” charade.

When dealing with scientific evidence and Daubert, establish that your experts are using generally accepted, standard scientific methodologies and data, while the defense is using a playbook designed to create doubt and disguise the truth.

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Gary DiMuzio is of counsel to Simmons Hanly Conroy in New York City and can be reached at gdimuzio@simmonsfirm.com.

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Notes

1. Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579 (1993).
2. Frye v. United States, 293 F. 1013, 1014 (D.C. Cir. 1923).
3. The Federal Rules of Evidence, not Frye, provide the standard for admitting expert scientific testimony in a federal trial. Daubert, 509 U.S. at 589.
4. Id. at 593–94.
5. Id. at 595 (“The focus, of course, must be solely on principles and methodology, not on the conclusions that they generate.”).
6. Id.
7. See Richard A. Lemen, Chrysotile Asbestos as a Cause of Mesothelioma: Application of the Hill Causation Model, 10 Int’l J. Occupational & Envtl. Health 233 (2004).
8. Daubert, 509 U.S. at 595.
9. Nat’l Research Council, Comm. on Identifying the Needs of the Forensic Scis. Cmty., Strengthening Forensic Science in the United States: A Path Forward 120 (2009), https://www.ncjrs.gov/pdffiles1/nij/grants/228091.pdf.
10. David L. Faigman et al., Modern Scientific Evidence: The Law and Science of Expert Testimony §1:15, at 47–48 (2013).
11. See, e.g., Alison Reid et al., Mesothelioma Risk After 40 Years Since First Exposure to Asbestos: A Pooled Analysis, 69 Thorax 843 (2014).
12. David L. Faigman, Expert Evidence: The Rules and the Rationality the Law Applies (or Should Apply) to Psychological Expertise, in Handbook of Psychology in Legal Contexts 367, 387 (David Carson & Ray Bull eds., 2d ed. 2003) (“Whether it is physics, biology, engineering, psychology, economics, sociology or anthropology, some questions can be approached experimentally, others require more indirect means, and most require an assortment of research strategies in order to approach an answer. This is why the so-called Daubert factors could never have been the test for all expert testimony.”).
13. Milward v. Acuity Specialty Prods. Grp., Inc., 639 F.3d 11 (1st Cir. 2011).
14. Lohrmann v. Pittsburgh Corning Corp., 782 F.2d 1156, 1163 (4th Cir. 1986).
15. Austin Bradford Hill, The Environment and Disease: Association or Causation?, 58 Proceedings of the Royal Soc’y Med. 295 (1965). For an in-depth discussion of Bradford Hill, see R. Jason Richards, Reflecting on Hill’s Original Causation Factors, Trial 44 (Nov. 2016); see also Lemen, supra note 7.
16. Hill, supra note 15, at 295–99; see also Lemen, supra note 7; Tara Tabatabaie, Decoding General Causation Data, Trial 28 (Apr. 2019).
17. Hill, supra note 15, at 299.
18. Id. at 295 (“There are, of course, instances in which we can reasonably answer these questions from the general body of medical knowledge . . . a particular chemical is known to be toxic to man and therefore suspect on the factory floor.”).
19. Id. at 299.
20. See World Health Org., Int’l Agency for Research on Cancer, IARC Monographs on the Identification of Carcinogenic Hazards to Humans: Preamble (2019), https://monographs.iarc.fr/wp-content/uploads/2019/07/Preamble-2019.pdf.
21. Id.
22. Fed. Judicial Ctr., Reference Manual on Scientific Evidence (3d ed. 2011), https://www.fjc.gov/sites/default/files/2015/SciMan3D01.pdf. 
23. Fed. Judicial Ctr., Reference Manual on Scientific Evidence, https://www.fjc.gov/content/reference-manual-scientific-evidence-third-edition-1.
24. Most states closely follow the federal rules and sometimes even expressly adopt federal cases, such as Daubert.
25. Fed. Judicial Ctr., supra note 22, at 640.
26. See Sander Greenland, Relation of Probability of Causation to Relative Risk and Doubling Dose: A Methodologic Error That Has Become a Social Problem, 89 Am. J. Pub. Health 1166 (1999).
27. Id. 
28. See William D. Ruckelshaus, Risk in a Free Society, 4 Risk Analysis 157–158 (1984).
29. Michael Borenstein et al., Criticisms in Meta-Analysis, in Introduction to Meta-Analysis 377, 379 (2009); see also Samuel Shapiro, Meta-analysis/Shmeta-analysis, 140 Am. J. Epidemiology 771 (1994).
30. The two most important “boutiques” are likely Cardno ChemRisk and Exponent. See David Michaels, Doubt Is Their Product, 292 Sci. Am. 96 (2005); David Michaels, Doubt Is Their Product: How Industry’s Assault on Science Threatens Your Health (2008); David Michaels, The Triumph of Doubt: Dark Money and the Science of Deception (2020).
31. For example, see Critical Reviews in Toxicology and Regulatory Toxicology and Pharmacology. For a discussion of these journals, see Jie Jenny Zou, Ctr. for Pub. Integrity, Science for Sale: Brokers of Junk Science? (Feb. 16, 2018), https://publicintegrity.org/environment/brokers-of-junk-science/.
32. See Michaels, The Triumph of Doubt, supra note 30; see also Rebecca F. Goldberg & Laura N. Vandenberg, Distract, Delay, Disrupt: Examples of Manufactured Doubt From Five Industries, 34 Rev. Envtl. Health 349 (2019); Mikael Karlsson, Chemicals Denial—A Challenge to Science and Policy, 11 Sustainability 4785 (2019); Thomas O. McGarity & Wendy E. Wagner, Bending Science: How Special Interests Corrupt Public Health Research (2008).
33. Benedetto Terracini & Dario Mirabelli, Asbestos and Product Defence Science, 45 Int’l J. Epidemiology 614 (2016).
34. John M. Dement & Hester J. Lipscomb, Discussion on “Mesothelioma in Drywall Finishing Workers,” by McCoy, M. J., Wolter, M. E., and Anderson, K. E., 9 J. ASTM Int’l 1 (2012).