Reference Manual on Scientific Evidence v3.0 – Disregarding Study Validity in Favor of the “Whole Gamish”

There is much to digest in the new Reference Manual on Scientific Evidence, third edition (RMSE 3d).  Much of what is covered is solid information on the individual scientific and technical disciplines covered.  Although the information is easily available from other sources, there is some value in collecting the material in a single volume for the convenience of judges.  Of course, given that this information is provided to judges from an ostensibly neutral, credible source, lawyers will naturally focus on what is doubtful or controversial in the RMSE.

I have already noted some preliminary concerns, however, with some of the comments in the Preface, by Judge Kessler and Dr. Kassirer.  See “New Reference Manual’s Uneven Treatment of Conflicts of Interest.”  In addition, there is a good deal of overlap among the chapters on statistics, epidemiology, and medical testimony.  This overlap is at first blush troubling because the RMSE has the potential to confuse and obscure issues by having multiple authors address them inconsistently.  This is an area where reviewers should pay close attention.

From first looks at the RMSE 3d, there is a good deal of equivocation between encouraging judges to look at scientific validity, and discouraging them from any meaningful analysis by emphasizing inaccurate proxies for validity, such as conflicts of interest.  (As I have pointed out, the new RSME did not do quite so well in addressing its own conflicts of interest.  SeeToxicology for Judges – The New Reference Manual on Scientific Evidence (2011).”)

The strengths of the chapter on statistical evidence, updated from the second edition, remain, as do some of the strengths and flaws of the chapter on epidemiology.  I hope to write more about each of these important chapters at a later date.

The late Professor Margaret Berger has an updated version of her chapter from the second edition, “The Admissibility of Expert Testimony,” RSME 3d 11 (2011).  Berger’s chapter has a section criticizing “atomization,” a process she describes pejoratively as a “slicing-and-dicing” approach.  Id. at 19.  Drawing on the publications of Daubert-critic Susan Haack, Berger rejects the notion that courts should examine the reliability of each study independently. Id. at 20 & n. 51 (citing Susan Haack, “An Epistemologist in the Bramble-Bush: At the Supreme Court with Mr. Joiner,” 26 J. Health Pol. Pol’y & L. 217–37 (1999).  Berger contends that the “proper” scientific method, as evidenced by works of the International Agency for Research on Cancer, the Institute of Medicine, the National Institute of Health, the National Research Council, and the National Institute for Environmental Health Sciences, “is to consider all the relevant available scientific evidence, taken as a whole, to determine which conclusion or hypothesis regarding a causal claim is best supported by the body of evidence.” Id. at 19-20 & n.52.  This contention, however, is profoundly misleading.  Of course, scientists undertaking a systematic review should identify all the relevant studies, but some of the “relevant” studies may well be insufficiently reliable (because of internal or external validity issues) to answer the research question at hand. All the cited agencies, and other research organizations and researchers, exclude studies that are fundamentally flawed, whether as a result of bias, confounding, erroneous data analyses, or related problems.  Berger cites no support for the remarkable suggestion that scientists do not make “reliability” judgments about available studies when assessing the “totality of the evidence.”

Professor Berger, who had a distinguished career as a law professor and evidence scholar, died in November 2010.  She was no friend of Daubert, but remarkably her antipathy has outlived her.  Her critical discussion of “atomization” cites the notorious decision in Milward v. Acuity Specialty Products Group, Inc., 639 F.3d 11, 26 (1st Cir. 2011), which was decided four months after her passing. Id. at 20 n.51. (The editors note that the published chapter was Berger’s last revision, with “a few edits to respond to suggestions by reviewers.”)

Professor Berger’s contention about the need to avoid assessments of individual studies in favor of the whole gamish must also be rejected because Federal Rule of Evidence 703 requires that each study considered by an expert witness “qualify” for reasonable reliance by virtue of the study’s containing facts or data that are “of a type reasonably relied upon by experts in the particular field forming opinions or inferences upon the subject.”  One of the deeply troubling aspects of the Milward decision is that it reversed the trial court’s sensible decision to exclude a toxicologist, Dr. Martyn Smith, who outran his headlights on issues having to do with a field in which he was clearly inexperienced – epidemiology.

Scientific studies, and especially epidemiologic studies, involve multiple levels of hearsay.  A typical epidemiologic study may contain hearsay leaps from patient to clinician, to laboratory technicians, to specialists interpreting test results, back to the clinician for a diagnosis, to a nosologist for disease coding, to a national or hospital database, to a researcher querying the database, to a statistician analyzing the data, to a manuscript that details data, analyses, and results, to editors and peer reviewers, back to study authors, and on to publication.  Those leaps do not mean that the final results are untrustworthy, only that the study itself is not likely admissible in evidence.

The inadmissibility of scientific studies is not problematic because Rule 703 permits testifying expert witnesses to formulate opinions based upon facts and data, which are not themselves admissible in evidence. The distinction between relied upon, and admissible, studies is codified in the Federal Rules of Evidence, and in virtually every state’s evidence law.

Referring to studies, without qualification, as admissible in themselves is wrong as a matter of evidence law.  The error has the potential to encourage carelessness in gatekeeping expert witnesses’ opinions for their reliance upon inadmissible studies.  The error is doubly wrong if this approach to expert witness gatekeeping is taken as license to permit expert witnesses to rely upon any marginally relevant study of their choosing.  It is therefore disconcerting that the new Reference Manual on Science Evidence (RMSE 3d) fails to make the appropriate distinction between admissibility of studies and admissibility of expert witness opinion that has reasonably relied upon appropriate studies.

Consider the following statement from the chapter on epidemiology:

“An epidemiologic study that is sufficiently rigorous to justify a conclusion that it is scientifically valid should be admissible,184 as it tends to make an issue in dispute more or less likely.185

RMSE 3d at 610.  Curiously, the authors of this chapter have ignored Professor Berger’s caution against slicing and dicing, and speak to a single study’s ability to justify a conclusion. The authors of the epidemiology chapter seem to be stressing that scientifically valid studies should be admissible.  The footnote emphasizes the point:

See DeLuca v. Merrell Dow Pharms., Inc., 911 F.2d 941, 958 (3d Cir. 1990); cf. Kehm v. Procter & Gamble Co., 580 F. Supp. 890, 902 (N.D. Iowa 1982) (“These [epidemiologic] studies were highly probative on the issue of causation—they all concluded that an association between tampon use and menstrually related TSS [toxic shock syndrome] cases exists.”), aff’d, 724 F.2d 613 (8th Cir. 1984). Hearsay concerns may limit the independent admissibility of the study, but the study could be relied on by an expert in forming an opinion and may be admissible pursuant to Fed. R. Evid. 703 as part of the underlying facts or data relied on by the expert. In Ellis v. International Playtex, Inc., 745 F.2d 292, 303 (4th Cir. 1984), the court concluded that certain epidemiologic studies were admissible despite criticism of the methodology used in the studies. The court held that the claims of bias went to the studies’ weight rather than their admissibility. Cf. Christophersen v. Allied-Signal Corp., 939 F.2d 1106, 1109 (5th Cir. 1991) (“As a general rule, questions relating to the bases and sources of an expert’s opinion affect the weight to be assigned that opinion rather than its admissibility. . . .”).”

RMSE 3d at 610 n.184 (emphasis in bold, added).  This statement, that studies relied upon by an expert in forming an opinion may be admissible pursuant to Rule 703, is unsupported by Rule 703 and the overwhelming weight of case law interpreting and applying the rule.  (Interestingly, the authors of this chapter seem to abandon their suggestion that studies relied upon “might qualify for the learned treatise exception to the hearsay rule, Fed. R. Evid. 803(18), or possibly the catchall exceptions, Fed. R. Evid. 803(24) & 804(5),” which was part of their argument in the Second Edition of the RMSE.  RMSE 2d at 335 (2000).)  See also RMSE 3d at 214 (discussing statistical studies as generally “admissible,” but acknowledging that admissibility may be no more than permission to explain the basis for an expert’s opinion).

The cases cited by the epidemiology chapter, Kehm and Ellis, both involved “factual findings” in public investigative or evaluative reports, which were independently admissible under Federal Rule of Evidence 803(8)(C).  See Ellis, 745 F.2d at 299-303; Kehm, 724 F.2d at 617-18.  As such, the cases hardly support the chapter’s suggestion that Rule 703 is a rule of admissibility for epidemiologic studies.

Here the RMSE, in one sentence, confuses Rule 703 with an exception to the rule against hearsay, which would prevent the statistical studies from being received in evidence.  The point is reasonably clear, however, that the studies “may be offered” to explain an expert witness’s opinion.  Under Rule 705, that offer may also be refused. The offer, however, is to “explain,” not to have the studies admitted in evidence.

The RMSE is certainly not alone in advancing this notion that studies are themselves admissible.  Other well-respected evidence scholars lapse into this position:

“Well conducted studies are uniformly admitted.”

David L. Faigman, et al., Modern Scientific Evidence:  The Law and Science of Expert Testimony v.1, § 23:1,at 206 (2009)

Evidence scholars should not conflate admissibility of the epidemiologic (or other) studies with the ability of an expert witness to advert to a study to explain his or her opinion.  The testifying expert witness really has no need to become a conduit for off-hand comments and opinions in the introduction or discussion section of relied upon articles, and the wholesale admission of such hearsay opinions undermines the court’s control over opinion evidence.  Rule 703 authorizes reasonable reliance upon “facts and data,” not every opinion that creeps into the published literature.

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