WILLIAM DAUBERT and JOYCE DAUBERT, Individually and As Guardians Ad Litem for JASON DAUBERT,
and ANITA DE YOUNG, Individually And As Guardian Ad Litem For ERIC SCHULLER,
Petitioners,

v.

MERRELL DOW PHARMACEURICALS, INC., Respondent,

ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE NINTH CIRCUIT

BRIEF AMICI CURIAE OF
CARNEGIE COMMISSION ON SCIENCE, TECHNOLOGY AND GOVERNMENT

BACKGROUND

The Nature of the Problem

The district court needs to know its obligation when confronted with an expert who seeks to testify where the scientific evidence is in dispute. Is it the judge's sole responsibility to determine, whether the expert is "qualified" by education and/or experience to be a witness? If that is the only test, critics contend that "junk science" may overwhelm decision making. The "qualified" witness may be a hired gun ready to say anything, or a proponent of fringe theories. On the other hand, allowing a court to screen a "qualified" expert’s opinion raises two problems: (1) Is this permissible under the Federal Rules of Evidence? and (2) How can a judge with no specialized scientific training know enough to make preliminary determinations that choose between the contentions of "qualified" experts?

The Nature of the Scientific Process

Any recasting of the judge's role in the handling of scientific evidence must take account of how science is conducted and how science can contribute to better decision making in the courts. The essential nature of science has been described as follows:

In broadest terms, scientists seek a systematic organization of knowledge about the universe and its parts. This knowledge is based on explanatory principles whose verifiable consequences can be tested by independent observers. Science encompasses a large body of evidence collected by repeated observations find experiments. Although its goal is to approach true explanations as closely as possible. its investigators claim no final or permanent explanatory truths. Science changes. It evolves.

The ongoing scientific endeavor must be viewed as a body of working assumptions, of contingent and sometimes competing scientific claims, likely to be refined even when the core insights are validated with the passage of time and under the glare of pluralistic criticism.

In light of this indeterminacy, how can a judicial system make use of a scientific "fact"? The dynamic nature of the scientific process suggests the impossibility of formulating any legal test of admissibility that requires a court to evaluate the validity of an evolving hypothesis or to choose between competing hypotheses. Amicus suggests instead that courts should focus on determining whether the expert engaged in recognized forms of scientific practice in reaching his or her conclusion.

SUMMARY OF ARGUMENT

The core issue in this ease is how the federal courts should think about scientific evidence. In the instant case this complex problem is presented in terms of admissibility, raising the issues of whether, when, and to what extent a federal judge may scrutinize an expert's opinion to determine whether it is admissible pursuant to the Federal Rules of Evidence.

We propose a new set of criteria geared to the process by which scientific hypotheses are developed - criteria that require the court to consider whether the scientific claim on which the expert's opinion rests is the product of a recognized form of scientific inquiry. An opinion that purports to answer a scientific question without having engaged in an appropriate scientific inquiry is incapable of providing a systematic explanation that satisfies our demand for rational proof.

We strongly urge this Court to go beyond the simplistic "general acceptance" test (Frye v United States, 1923). "General acceptance" is an inadequate vehicle for thinking about science in the courtroom. It fails to provide federal judges with sufficient guidance on how to analyze complex scientific issues because its formula is too vague and misleading, and is incompatible with the essence of the scientific endeavor. The unresponsiveness of "general acceptance" to the scientific process leads to an unprincipled test that taken literally rejects valuable insights that bear all the hallmarks of acceptable science, but provides no guidance on how to distinguish the product of marginal or insupportable fringe activities.

We also argue that making peer review a sole condition for the admissibility of scientific evidence is ill-advised. Imposition of such a requirement does not reflect the realities of either litigation or the role of science in litigation.

ARGUMENT

An expert opinion that is purportedly based on scientific observation is of value in resolving a controverted issue only if it embodies a scientifically plausible mode of reasoning. Separating valid from invalid hypotheses requires that the judge understand science as a process of producing claims about the actual world. It does not require that a judge understand or undertake an extensive examination of the hypotheses being put forth.

We suggest that when a court is ruling on the admissibility of expert testimony grounded in science it should determine whether scientific claims have been developed within the bounds of a recognizable form of scientific inquiry. In order to make this inquiry, the court should consult the following criteria:

• Is the claim being put forth testable?
• Has the claim been empirically tested?
• Has the testing been carried out according to a scientific methodology?
• The opinion should be rejected if the answer to any of these questions is in the negative.

Ordinarily, if plaintiff and defendant have presented conflicting hypotheses that are the product of an appropriate scientific inquiry, the jury will have to resolve the controverted issues.

Whether evidence is sufficient is a matter of law, not science. In scientific hypothesis-, testing, the hypothesis being investigated is accepted only if the data obtained would be quite unlikely to result if the hypothesis were not true. When scientists reject the hypothesis, they are not making a statement of an established "truth." They are making a probabilistic statement given the current state of knowledge. Determining the legal consequences that flow from this imperfect state of knowledge lies beyond the domain of science.

It is a court that must decide whether the degree of scientific uncertainty is such that the plaintiff has failed to introduce sufficient probative evidence to meet its burden of proof. When the plaintiff is seeking compensation for injuries allegedly suffered because of exposure to a toxic substance, for instance, it is the judge and not a scientist who must bear ultimate responsibility for determining whether the scientific evidence satisfies the legal standard of proof. In ruling on sufficiency, the court, therefore, properly evaluates the present state of available scientific knowledge. Since determinations about the sufficiency of scientific evidence entail policy concerns, the court will also have to consider the underlying objectives of science and the law in order to ascertain the extent to which scientists' conclusions have relevance for the legal system.

A. Peer Review as a Sole Condition Is Incompatible with the Realities of Litigation.

Insisting that parties’ responses to this ongoing process be limited to studies that have been peer-reviewed is unresponsive to the constraints imposed by litigation. How can lawyers prepare if the competence of their experts to testify is contingent, not on the scientific nature of their work, but on whether it will have been accepted for publication by the time a motion for summary judgement is made? Suppose the editorial review of the paper is in the process of negotiation - must the legal process halt?

B. Peer Review as a Sole Condition Is Incompatible with the Role of Science in Litigation.

Peer review is not an objective, universally accepted set of procedures but rather a process that reflects the social processes and social conflicts that underlie scientific, claims. The peer review process operates in part to clarify and to improve work presented for publication, and in part to make particular scientific research communities relatively immune to criticism from outsiders. Consequently, a person who is advocating a view at odds with the currently received wisdom may encounter difficulties in having his or her work published.

The real purpose of peer review, however, is not getting the article into the journal, but the fact of its publication - which makes the claims accessible to the skepticism of the larger scientific community. This important and constructive gatekeeping function of peer-review is the reason we endorse its use as a factor indicating proper scientific practices.

For these reasons as well as the practical concerns noted earlier, submission to peer- review should be regarded as a favorable attribute, but the lack of peer-review should not be treated as a conclusive factor mandating exclusion of an expert.

CONCLUSION

Our objective has been to delineate more precisely when law should defer to science, and when science must give way to the law. The tests that judges currently use in ruling on the admissibility of expert proof grounded in science are not adequately geared to the nature of the scientific enterprise.

For the foregoing reasons, the Court should clarify the standard to be used in determining the admissibility of scientific evidence.