The problem of the testifying historian expert witness is perhaps most serious in product liability cases, where both plaintiffs and defendants hope to inject historian opinion testimony into the trial to give, in essence, an interim closing argument.  Increasingly, courts have grown wary of this thinly disguised ploy and barred such testimony.  The most recent example of judicial impatience with the ploy of having an expert witness give a narrative of historical events is MDL 1909, In re Gadolinium-Based Contrast Agents Products Liability Litigation, 2010 WL 1796334, *13 (N.D.Ohio May 4, 2010).  In the gadolinium litigation, Judge Polster ruled that  expert witnesses may not provide narrative histories of the product, but rather the parties must present the history of the product and its regulation through direct evidence.  In addition, expert witnesses may not testify about the knowledge, state of mind, motivation, or intent of the parties.

Next month, the International Commission on Occupational Health (ICOH) is sponsoring the 4th International Conference on the History of Occupational and Environmental Health, in San Francisco.  I will be presenting on the problematic nature of historian expert witness opinion testimony, on June 22.  The abstract of the paper to follow is set out below.

Courting Clio:  Historians and Their Testimony in Products Liability Litigation

By Schachtman, N.A.*, and Ulizio, J.A.¹

            Parallel developments in mid-20^th century medicine and American tort law resulted in the need to resolve factual disputes about events several decades old.  After World War II, epidemiology developed the assessment of case-control and cohort studies to permit reliable detection and quantification of causal associations between diet, medications, social habits, and occupational or environmental exposures and various chronic diseases.  Latency periods, often decades long, complicated but did not prevent the identification of causes of cancer and other diseases — such as tobacco, asbestos, DES, radiation, among others.

            Also in the middle of the last century, American law evolved to extend manufacturers’ and sellers’ duties in tort to prevent harm from defective products, not only to immediate purchasers but to all foreseeable users.  Contributory fault, which had barred recovery, gave way to comparative fault, which only reduced damages.  Most important, statutes of limitations, which previously barred suits filed after two years or so from last exposure, were modified to permit suits within two years of when the claimant’s injury became clinically manifest and discoverable.  With these developments, injured workers became entitled to sue for injuries caused by products, even though the causal exposures occurred decades earlier.

            These advances in epidemiology and tort law have put into issue factual disputes over who knew what about product risks, many years before the injury and the lawsuit.  Parties on both sides have struggled to interpret old medical texts and documentary evidence, on evidentiary records often incomplete and ambiguous.  The meaning of the old scientific evidence was typically beyond the ken of ordinary lay persons, and thus litigants sought expert witnesses, with expertise in historical methods or medical science, or both, to explain and present the historical evidence.

 The advent of historian expert witnesses in tort cases has raised legal questions about how courts should supervise and control the reliability and advocacy of historian witnesses.  The narrative typically created by historians threatens to usurp the lawyers’ role in interpreting and arguing the evidence and inferences to the jury, and the jurors’ role in finding the facts from the evidence in the case. 

The early judicial response frequently relied upon vigorous crossexamination to reveal historians’ use of incomplete or misleading evidence.  More recently, legal writers have criticized judicial passivity in the face of tendentious historical expert opinion testimony.  Various proposals, ranging from heightened judicial scrutiny and gatekeeping for historian witnesses, to appointment of neutral witnesses, to eliminating or reducing the scope of historians’ testimony, have been suggested.  Recent case law shows no clear path to resolving the difficulties inherent in the reliance upon historians’ opinion testimony in tort cases.

The history of the occupational disease silicosis, and historians’ testimony in the litigation of silicosis claims over the last two decades, will be used as a case study of the utility and dangers in having historians serve as expert witnesses. 

*Lawyer in private practice; Lecturer, Columbia Law School.

¹Lawyer, and Chief Executive Officer of U.S. Silica Co.

An historian testifying as an expert witness is a bit like a dog cutting your lawn — You don’t care whether the dog mows in a straight line, or cuts too high or too low, or even whether the dog rakes up after cutting.  Dogs should not be cutting the grass at all.

Historians may have a great deal to contribute to litigation by identifying primary sources and suggesting lines of argument or narratives from the evidence that they collect and synthesize.  Historians’ testimony, however, should not substitute for lawyers’ proving their cases by admissible evidence, and by persuading the fact finder with argument.  The principal problem with historian expert witness testimony is that it circumvents the rules of evidence, and injects final argument into the middle of the trial in the guise of testimony.  Lawyers might welcome this opportunity for an additional final argument, and for the relief from the tedium of actually proving the factual predicate of their cases, but expedience is a slim justification that does not outweigh circumventing the structure of the trial and rules of evidence.

Caution!  Suggesting that historians should not serve as expert witnesses may cause the dog to bite.  See, e.g., D. Rosner & G. Markowitz, “The Trials and Tribulations of Two Historians:  Adjudicating Responsibility for Pollution and Personal Harm, 53 Medical History 271, 280-81 (2009)(criticizing legal counsel for expressing the view that historians should not be permitted to testify and thereby circumvent the rules of evidence); D. Rosner & G. Markowitz, “L’histoire au prétoire.  Deux historiens dans les procès des maladies professionnelles et environnementales,” 56 Revue D’Histoire Moderne & Contemporaine 227, 238-39 (2009) (same); D. Rosner, “Trials and Tribulations:  What Happens When Historians Enter the Courtroom,” 72 Law & Contemporary Problems 137, 152 (2009) (same).

Apparently historians do not have prohibitions against duplicative (or triplicative) publications.

The Betz case, which relied upon an overruled federal court case, has other surprises for Pennsylvania lawyers.

On appeal, Betz argued that her expert witnesses’ opinions that “each and every fiber contributes to the disease process,” were not novel as evidenced by Pennsylvania’s courts routine acceptance of such testimony.   Betz v. Pneumo Abex LLC, 2010 Pa. Super. 74, slip op. at 24 & n.17.    The appellant’s contention is certainly correct as an historical matter; Pennsylvania courts have indulged the fiction of “each and every fiber” for decades.  I can recall hearing this opinion from a plaintiff’s expert witness, in a Philadelphia courtroom, in my first asbestos trial, almost 25 years ago.  After shaking off my amazement, I inquired:  “How do you know this?”  The response that I got from the witness was that he did not know how to distinguish between and among fibers so he had to blame them all.  My earnest motion to strike the testimony as having no basis was refused.

In later trials, I pressed harder.  “Is it true that many inhaled fibers are quickly exhaled?”  These fibers do not contribute to any disease process. “Is it true that many fibers inhaled are brought up by the muco-ciliary escalator, and then spit out or swallowed?”  Again, these fibers do not contribute to any disease process in the lungs.  “Is it true that many fibers are inhaled and retained, and are then engulfed by macrophages and taken to lymph nodes?”  Again, these fibers became non-combatants.  “Of the fibers that migrated to the pleura or close to the pleura, some went through the right lung, and some through the left lung, but the fibers on the side opposite the mesothelioma did not contribute?”  “Although you gave your ‘each and every fiber’ opinion, some fibers – chrysotile – break down in the body within months because they are not as resistant as amphibole fibers; true?”  These questions would elicit concessions or professions of ignorance, but I still lost my motions to strike the “each and every fiber” opinion, each and every time.

In Betz, the defendants called plaintiffs’ expert witnesses on their ipse dixit.  The “each and every fiber” opinion may be generally accepted opinion testimony in courtrooms, but it has no acceptance in the scientific community.  The Superior Court appeared to sidestep the argument that long-standing judicial toleration of unsupported opinion equals “general acceptance,” but what is noteworthy is that the Court did not dismiss it out of hand.  Pennsylvania’s version of Frye applies to allow opinions when “the relevant scientific community has generally accepted the principles and methodology the scientist employs”    Betz, slip op. at 21 (quoting from Trach v. Fellin, 817 A.2d 1102, 1110 (Pa. Super. 2003)(en banc)).  How judicial acquiescence in an opinion, without any meaningful scientific scrutiny, can substitute for a determination of general acceptance in the relevant scientific community is a mystery that calls for resolution from a higher court.

In Betz, the Superior Court’s resolution of the issue seems to lie in modifying the proponent’s burden of proving the lack of novelty into a burden on the opinion’s opponent to prove novelty.  But even with this shifting of the burden, the Superior Court seems to have lost sight of the complete absence of the “each and every fiber contributes” opinion from any textbook, article, or other scientific source.

The Superior Court went further than shifting the burden; it also suggested that studies conducted or sponsored by industry were unworthy of consideration when addressing the Frye issues.  The Court cited Justice Castille’s dissent in Blum v. Merrell Dow Pharmaceuticals, Inc., 563 Pa. 3, 13-15, 764 A.2d 1, 5-7 (2000), where he argued that courts should be wary of an orthodoxy created by “purchased research and the manipulation of scientific literature.”  Betz, slip op. at 26 n. 19.  What the Superior Court failed to recognize, however, is that the industry-sponsored study relied upon by the defense expert witnesses was a meta-analysis, which was as open and transparent as imaginable.  A meta-analysis simply takes the data from other published studies and calculates a summary estimate of risk for the entire dataset.  The meta-analysis in question included studies funded or sponsored by a various groups, including those that had no relationship to the litigation.  If the plaintiff believed that any important studies were omitted, it would have been relatively easy to challenge the scholarship or statistical analysis in the meta-analysis, and to have presented a revised analysis.  There was, simply put, no evidence of manipulation by industry to create an “orthodoxy.”  The Superior Court’s citation of Justice Castille’s dissent appears to have been completely gratuitous.

On April 30, 2010, the Pennsylvania Superior Court, sitting en banc, reversed the grant of summary judgment to brake manufacturers in an asbestos product liability case.  Betz v. Pneumo Abex LLC, 2010 Pa. Super. 74.  http://www.superior.court.state.pa.us/opinions/E02001_09.pdf  The plaintiff claimed that his work in the automotive repair industry had exposed him to asbestos from brakes and clutches, and that this exposure caused him to develop mesothelioma.  The brake manufacturers moved to exclude what they claimed were  the novel scientific opinions of plaintiff’s expert witnesses on medical causation.  The trial court held that the plaintiff’s expert witnesses opinions failed to satisfy Pennsylvania’s requirement of “general acceptance,” and excluded their opinions.  Finding the plaintiff without any admissible expert witness opinion to support for his causal claim, the trial court them granted summary judgment.  

In reversing the trial court’s summary judgment, the en banc panel managed to add to the confusion that is Pennsylvania’s law on expert witnesses.  Perhaps the best that can be said for the Betz decision is that one member of the panel, Judge Shogan concurred in the result, and wrote separately to suggest that the Pennsylvania Supreme Court “clarify the appropriate approach to be taken in cases involving experts employing extrapolation as a methodology to support their scientific opinions.”  Id. Concurring Statement, p.3.  Lawyers who practice in Pennsylvania, and who depend upon appellate court guidance on such matters, would welcome such clarification.

There are several remarkable aspects of the en banc court’s decision.  For now, let me point out the incoherence of the Superior Court’s reliance upon a non-Pennsylvania case that is a derelict upon the waters of federal expert witness law:  Ferebee v. Chevron Chemical Co., 736 F.2d 1529 (D.C. Cir. 1984).  The court cited to Ferebee with obvious enthusiasm and approval, but without any acknowledgement that Ferebee‘s holding with respect to expert witness testimony was dubious when delivered in 1984, and has been overruled by the United States Supreme Court in 1993, in that Court’s Daubert decision. Perhaps more troubling yet is the Pennsylvania court’s quotation of the most controversial, and the most thoroughly discredited dictum from Ferebee:

“Judges, both trial and appellate, have no special competence to resolve the complex and refractory causal issues raised by the attempt to link low-level exposure to toxic chemicals with human disease.  On questions such as these, which stand at the frontier of current medical and epidemiological inquiry, if experts are willing to testify that such a link exists, it is for the jury to decide whether to credit such testimony.”

Betz, slip op. at 43 (quoting Ferebee, 736 F.2d at 1534).  This passage from Ferebee signifies that courts have no screening function once experts with appropriate qualifications appear, willing to offer opinions.  Of course, this aspect of Ferebee is utterly at odds with the last 17 years of federal court evidence law, just as it was at odds with most federal circuits at the time it was written.  Lawyers in Pennsylvania might well interpret this pronouncement from the Superior Court – an embrace of an  outmoded, discredited, and clearly overruled case – to be a signal that Pennsylvania has abandoned completely any judicial screening and review of expert witness testimony.  This part of the Betz decision is particularly disturbing given that the law of expert witness qualifications sets a very low standard; the witness needs only “a reasonable pretense of expertise” in Pennsylvania to offer an “expert” opinion.  Judge Shogan is clearly right that the Pennsylvania Supreme Court will now be needed to put the law of expert witnesses in Pennsylvania back on track.

The Supreme Court’s decision in Joiner was an important qualification to its earlier decision in Daubert.  Joiner correctly adjusted the dicta in Daubert that suggested that conclusions could not be evaluated for their reliability, a correction that is now embodied in Federal Rule of Evidence 702.  Joiner correctly assessed that plaintiffs’ expert witnesses in that case were relying upon pathologically deficient and unreliable evidence.  (Some of the expert witnesses in Joiner are known repeated offenders against Rule 702.)  Furthermore, in reversing and rendering a judgment of the 11^th Circuit, Joiner corrected the asymmetric standard of review for Rule 702 witness exclusions that the 11^th and other Circuits were using.

In reaching the right result, and in advancing the jurisprudence of the reliability of expert witness opinion testimony, Joiner, however, stumbled on one important analysis.  In his opinion in Joiner, Chief Justice Rehnquist gave considerable weight to the consideration that the plaintiffs’ expert witnesses relied upon studies, the authors of which explicitly refused to interpret as supporting a conclusion of human disease causation.  See General Electric Co. v. Joiner, 522 U.S. 136, 145-46 (1997) (noting that the PCB studies at issue did not support expert witnesses’ conclusion that PCB exposure caused cancer because the study authors, who conducted the research, were not willing to endorse a conclusion of causation). 

Although the PCB study authors were well justified in their respective papers in refraining from over-interpreting their data and analyses, this consideration is of doubtful general value in evaluating the reliability of an expert witness’s proposed testimony.  First, as some plaintiffs’ counsel have argued, the testifying expert witness may be relying upon a more extensive and supportive evidentiary display than considered by the study authors.  The study, standing alone, might not support causation, but when considered with other evidence, the study could take on some importance in supporting a causal conclusion.  (This consideration would not save the sadly deficient opinions challenged in Joiner.) Second, there are important methodological considerations that render the Discussion sections of published papers of little value.  They are almost never comprehensive reviews of the subject matter, and they are often little more than the personal opinions of the study authors.  Sometimes, the Introduction and Discussion sections are influenced by the need to get the paper published and satisfy the whims of peer reviewers and editors.  Thus, these sections, in addition to being uncross-examined statements of the authors, might well reflect also second-level hearsay, of opinions of anonymous reviewers, whose expertise, biases, and perceptions cannot be challenged.

 The use of a paper’s Discussion section to measure the reliability of a proffered expert testimony runs contrary to how scientists generally read and interpret papers.  Chief Justice Rehnquist’s emphasis upon the study authors’ Discussion of their own studies ignores the first important principal of interpreting medical studies, in an evidence-based world view:  In critically reading and evaluating a study, one should ignore anything in the paper other than the Methods and Results sections.

There are many clear statements in the medical literature, which caution the consumers of medical studies against misleading claims.  Several years ago, the British Medical Journal published a paper by Montori, et al., “Users’ guide to detecting misleading claims in clinical research reports,” 329 Br. Med. J. 1093 (2004).  The authors distill their advice down to six suggestions in a “[g]uide to avoid being misled by biased presentation and interpretation of data, the first [suggestion] of which is to:  “Read only the Methods and Results sections; bypass the Discuss section.”  Id. at 1093 (emphasis added).

Perhaps the Discussion section, in the context of a Rule 104(a) proceeding, has some role in evaluating the challenged expert witness’s opinion, but surely it is a weak factor at best.  And clearly, the disagreement with the study authors’ conclusions or opinions, as reflected by speculative Discussion sections, can cut both ways.  Study authors may downplay their findings – appropriately or inappropriately, but study authors often overplay their findings and distort or misinterpret how their findings fit into the full picture of other studies and other evidence.  The quality of peer-reviewed publications is simply too irregular and unpredictable to make the subjective, evaluative comments in hearsay papers the touchstone for admissibility or inadmissibility.

Furthermore, courts should be asking why a testifying expert witness, or the witnesses who are countering the challenged witness, should advert to the Discussion section of a published article.  If an expert witness cannot interpret the Methods and Results sections, then in all likelihood he or she lacks the requisite expertise to offer a reliable opinion.

Joiner’s misplaced emphasis upon study authors’ Discussion sections has gained a foothold in the case law interpreting Rule 702.  In Huss v. Gayden, 571 F.3d 442  (5th Cir. 2009), for example, the Court declared:

“It is axiomatic that causation testimony is inadmissible if an expert relies upon studies or publications, the authors of which were themselves unwilling to conclude that causation had been proven.”

Id. (citing Vargas v. Lee, 317 F.3d 498, 501-01 (5^th Cir. 2003) (noting that studies that did not themselves embrace causal conclusions undermined the reliability of the plaintiffs’ expert witness’s testimony that trauma caused fibromyalgia), and McClain v. Metabolife Int’l, Inc., 401 F.3d 1233, 1247-48 (11^th Cir. 2005) (expert witnesses’ reliance upon studies that did not reach causal conclusions about ephedrine supported the challenge to the reliability of their proffered opinions).

This aspect of Joiner perpetuates an authority-based view of science to the detriment of requiring good and sufficient reasons to support the testifying expert witnesses’ opinions.  The problem with Joiner’s suggestion that expert witness opinion should not be admissible if it disagrees with the study authors’ Discussion section is that sometimes study authors grossly over-interpret their data.  When it comes to scientific studies written by “political scientists” (scientists who see their work as advancing a political cause or agenda), then the Discussion section often becomes a fertile source of unreliable, speculative opinions that should not be given credence in Rule 104(a) contexts, and certainly should not be admissible in trials.

There have been, and will continue to be, occasions in which published studies contain data, relevant and important to the causation issue, but which studies also contain speculative, personal opinions expressed in the Introduction and Discussion sections.  The parties’ expert witnesses may disagree with those opinions, but such disagreements hardly reflect poorly upon the testifying witnesses.  Neither sides’ expert witnesses should be judged by those out-of-court opinions.  Perhaps the hearsay Discussion section may be considered under Rule 104(a), which suspends the application of the Rules of Evidence, but it should hardly be an important or dispositive factor, other than raising questions for the reviewing court.

Expert witnesses should not be constrained or excluded for relying upon study data, when they disagree with the hearsay authors’ conclusions or discussions.  Given how many journals cater to advocacy scientists, and how variable the quality of peer review is, testifying expert witnesses should be required to have the expertise to interpret the data without substantial reliance upon, or reference to, the interpretative comments in the published literature.