In 1993, the Supreme Court decided DAUBERT v. MERRELL DOW PHARMACEUTICALS, INC. weighing in on one of the then
most pressing issues in
the law of evidence: what was the appropriate standard for admitting expert evidence in federal court? The Court
directed that district judges act as "gatekeepers" by ensuring that proffered expert evidence was both
relevant and reliable. To make this determination, judges were to examine the reasoning of the expert and the
methods used to draw conclusions and develop opinions. In so doing, the Court rejected the mechanical test used
by some courts that had restricted the district judge's role to an evaluation of whether the expert's position
was "generally accepted" in the relevant field.
The real world impact of the DAUBERT decision in civil cases in federal court is the topic of Lloyd Dixon and Brian
Gill's Rand Institute study. The study's bottom line is that "it appears that judges are indeed doing what
they were directed to do by the Supreme Court: they are increasingly acting as gatekeepers for reliability and
relevance, they are examining the methods and reasoning underlying the evidence, and they appear to be employing
general acceptance as only one of many factors that enter into their reliability assessments" (p. xiii).
Although modest in appearance, this study should not be underestimated. It makes a valuable, if incremental
contribution to the evolving understanding of how the DAUBERT standard is actually working.
The study is structured in eight chapters, presented along with a useful introductory summary as well as four detailed
appendices devoted principally to statistical information underlying the study's conclusions. The authors begin
by setting the stage for the study (Chapter 1). They then provide an overview or what they term a "conceptual
analysis" of DAUBERT with respect to the disposition of challenged expert evidence, including a discussion
of the respective roles of the parties and the court in the process (Chapter 2). After explaining their methodology
(Chapter 3), Dixon and Gill present their empirical findings (Chapters 4 through 7). Finally,
they summarize their principal findings as well as their suggestions for future study to address areas beyond the
scope of their report (Chapter 8). Overall, the structure of the report is conducive to either a quick read or
a more detailed analysis.
The authors based their study on a review of 399 federal district court opinions issued between January 1980 and
June 1999. The district court judges made rulings with respect to the admissibility of 601 separate
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pieces of expert evidence the parties proffered in these cases. Thirty-eight percent of these pieces of evidence
were in the period prior to DAUBERT while the remaining sixty-two percent concerned post-DAUBERT evidentiary decisions
(pp. 19-20).
As explained in detail in the study, the authors attempted to analyze the data in such a way as to control for
variables other than the DAUBERT decision that could have had an effect on the trends noted in the admission of
expert evidence. Such efforts included controlling for case type (e.g., product liability, antitrust, non-employment
civil rights, etc.), federal circuit, and substantive type of evidence (e.g., medical, social science, business,
etc.) (pp. 19-24). I will not try to describe the study's control efforts here. Suffice it to say, the authors
provide a full and convincing explanation of their methods and the bases for the conclusions they draw from the
data.
The principal contribution of the study is its well-supported conclusion that judges actually have changed their
scrutiny of expert evidence after DAUBERT in accord with the Supreme Court's direction. Without such empirical
work, we would be left with nothing more than a collection of anecdotes about any change. Moreover, one would
never be sure if the anecdotes reflected a substantive change in the standard for admission of evidence or were
merely the result of a change in terminology (i.e., simply using the word "reliability" as a means of
exclusion when the substantive standard applied had not changed). In the chapters presenting their data, Dixon
and Gill provide convincing support for the proposition that the changes in exclusion patterns resulted from a
true shift in substance and not merely a name game (chapters 4-7).
Along the way, the study also sets out other interesting findings, equally well-supported by the data, concerning
the admission of expert evidence. For example, it appears that in addition to increasing their scrutiny of expert
evidence based on reliability, district judges also generally took a more detailed approach to the consideration
of expert evidence after DAUBERT, including conducting a more searching review of relevance and expert qualifications
(chapter 6.2). In short, it appears that judges began to feel more empowered to enter into what could have been
seen as the general province of the jury before DAUBERT.
In addition, the data collected as part of the study indicate that the DAUBERT decision appears to have started
an almost iterative process between judges evaluating evidence on the one hand and lawyers either proposing or
challenging that evidence on the other. As explained by Dixon and Gill, for example, it seems that in the first
years after DAUBERT the rate of evidence excluded based on a lack of reliability rose. In about 1997, the percentage
of such excluded evidence began to decline. The authors hypothesize that this decline could have been caused by
several possible factors concerning the behavior of the advocates, including, for example, a decision by proponents
to be more conservative in what evidence they tried to admit (p. 31). In any event, the discussion of this process
may be of interest to those who think and write about civil litigation more generally.
Of course, this study does not address all of the questions that DAUBERT and its progeny still raise. However,
the authors are quite clear that they understand that their study has limits. In fact, one of the study's strengths
is its recognition of what still needs to be addressed (pp. 64-66). The
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principal question that is not addressed in this study, and perhaps the single most vexing question in this area
today, as well as being the major basis of Chief Justice Rehnquist's dissent in DAUBERT itself, is whether district
judges are doing, or are able to do, a good job as gatekeepers. As Dixon and Gill recognize, the fact that more
evidence was excluded standing alone does not mean that such evidence was properly excluded (e.g., p. 30). The
authors quite rightly suggest that further work should be done to address this question.
The study is not, however, without some minor shortcomings. For example, one avenue for additional investigation
that the authors do not discuss in any great detail is a comparison of the federal experience under DAUBERT with
the experiences of state courts, both those that have adopted the DAUBERT standard and those that either have rejected
it or have not yet considered a change in the trial judge's role. Although the authors mention two studies that
did address certain issues involving state court judges' views concerning DAUBERT, neither of those studies really
goes to the heart of the issues addressed here. For example, one of them dealt with the attitudes of the judges
towards DAUBERT itself. Moreover, it does not appear that there has been any study of whether non-DAUBERT states
experienced any similar increase in the percentage of expert evidence excluded during the relevant period (p. 6).
In short, some further discussion of these earlier
studies and what the authors believe could usefully be done with respect to a comparative analysis of state courts
in this area would have been helpful.
Another part of the study I found somewhat unsatisfying concerned the authors' tentative conclusion that "[c]hallenges
to expert evidence increasingly resulted in summary judgment after DAUBERT" (p. 62). To begin with, it did
not appear that this conclusion had the same level of support in the data with respect to causation that the authors
were so good at documenting with respect to the remainder of their work. Moreover, the authors go on to state
as one of their "next steps" that they have "limited information on what effect DAUBERT has had
on case outcomes" (p. 65). This latter point seems at least partially at odds with the former.
The bottom line for this study is that the very minor quibbles one can have with it in no way detract from the
important contribution it makes to the study of DAUBERT and the decision's real world impact in the federal courts.
One can only hope that the authors, or others, will continue to explore this topic along the lines suggested in
the study itself.
CASE REFERENCE:
DAUBERT v. MERRELL DOW PHARMACEUTICALS, INC., 509 U.S. 579 (1993).
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Copyright 2002 by the author, Michael P. Allen.