Federal standards for admissibility of expert evidence on causation.

• Author: Slater, Angela D.

THE Federal Rules of Evidence, enacted in 1975, govern the use of expert testimony in federal courts, and they have been adopted or adapted in many states. The Federal Rules were designed in part to broaden the standards for the admissibility of expert testimony. Thus, it is not surprising that the use, and arguably abuse, of expert testimony has increased tremendously since their enactment.

Through the years, courts have been increasingly required to make pretrial inquiries into the bases of expert opinions to determine their admissibility. At first, the standards were minimal. If purported experts possessed either the appropriate academic degree or the requisite experience in the subject area, they generally were permitted to testify without any substantive judicial inquiry into the basis or reliability of their opinions. Many federal courts viewed challenges to expert testimony as affecting the weight, not the admissibility of the testimony.

In recognition of the critical importance of expert testimony, particularly in the toxic tort area, federal courts finally began to scrutinize proffered testimony to determine admissibility. They have relied on three of the Federal Rules--702, 703 and 403.

Rule 702 provides:

If scientific, technical, or other specialized

knowledge will assist the trier of fact to under-

stand the evidence or to determine a fact in is-

sue, a witness qualified as an expert by knowl-

edge, skill, experience, training, or education,

may testify thereto in the form of an opinion or

otherwise.

Rule 703 provides:

The facts or data in the particular case upon

which an expert bases an opinion or inference

may be those perceived by or made known to the

expert at or before the hearing. If of a type rea-

sonably relied upon by experts in the particular

field in forming opinions or inferences upon the

subject, the facts or data need not be admissible

in evidence.

Rule 403, the "balancing" rule, provides:

Although relevant, evidence may be excluded

if its probative value is substantially outweighed

by the danger of unfair prejudice, confusion of

the issues, or misleading the jury, or by consid-

erations of undue delay, waste of time, or need-

less presentation of cumulative evidence.

In addition to the analysis under Rules 702 and 703, federal courts also must scrutinize the proffered testimony under 403 to balance its probative value against the risks of unfair prejudice, confusion of the issues or misleading the jury. Even if testimony satisfies the requirements of 702 and 703, courts have discretion to exclude it under 403. Many courts have held, however, that pretrial exclusions of expert testimony under Rule 403 should be granted rarely. Indeed, the Third Circuit concluded in In re Paoli Railroad Yard PCB Litigation(1) that Rule 403 is a trial-oriented rule. To excluse evidence under it at the pretrial stage, a court must have a complete record on the point at issue, amounting to a virtual surrogate for a trial record.

Prior to the Federal Rules, the standard for admission of expert testimony was "general acceptance," as enunciated by Frye v. United States.(2) The Frye court instructed, "While courts will go a long way in admitting expert testimony deduced from a well-recognized scientific principle or discovery, the thing from which a deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs."

From the enactment of the Federal Rules in 1975 to the U.S. Supreme Court's 1993 decision in Daubert v. Merrell Dow Pharmaceuticals Inc.(3) there was extensive debate among courts and commentators as to whether the Federal Rules limit or supersede the Frye "general acceptance" standard in favor of a more liberal relevancy standard.(4) While Frye was the majority view, a minority of federal courts had rejected it in favor of a more liberal relevancy standard arguably embodied in the Federal Rules.(5)

The Supreme Court resolved the debate in Daubert, holding that the "general acceptance" standard was displaced by the Federal Evidence Rules, but emphasizing that the rules themselves place limits on admissibility. Focusing on Rule 702, the Court concluded that the concept of "scientific knowledge" in the rule "implies a grounding in the methods and procedures of science ... /and/ connotes more than subjective belief or unsupported speculation." The Court interpreted the Rule 702 requirement that expert testimony "assist the trier of fact" as one of relevance--that is, the proffered testimony must have "a valid scientific connection to the pertinent inquiry as a precondition to admissibility."

The Court offered some "general observations" to be considered by trial judges under Rule 104(a) when assessing expert testimony: (1) whether the scientific technique or theory can be, and has been, tested; (2) whether the theory or technique has been subjected to peer review and publication; (3) associated with the technique; and (4) whether the technique or theory has gained "widespread acceptance."

The Court concluded by holding that while "general acceptance" is not prerequistite to admissibility, the Federal Rules themselves require the trial judge to ensure that the expert evidence "rests on a reliable foundation and is relevant to the task at hand."

SUBJECT MATTER OUTSIDE COMMON KNOWLEDGE OF JURY

Before reaching the issues of experts' qualifications and the bases for their opinions, courts must determine the threshold issue of whether expert testimony is needed. Traditionally, the subject matter of expert testimony had to be beyond the ken of the average juror. Under the Federal Rules, the standard as to whether expert testimony is warranted is whether it will "assist the trier of fact." As one commentator has stated, "[t]here is no more certain test for determining when experts may be used than the common sense inquiry whether the untrained layman would be qualified to determine intelligently and to the best possible degree the particular issue without enlightenment from those having a specialized understanding of the subject involved in the dispute."(6)

Combining both common law and the Federal Rules, courts have concluded that expert testimony is not permitted if it is within the knowledge of the average juror or if it will not assist the trier of fact. If the court determines that the subject matter of an expert's testimony is not beyond the common knowledge of the average juror and, for that reason, will not assist the trier of fact, then the expert is not permitted to testify.(7)

QUALIFICATIONS

Rule 702 sets forth two discrete requirements for expert testimony. First, a witness must be "qualified" as an expert by knowledge, skill, experience or education; second, an expert's scientific, technical or other specialized knowledge must "assist the trier of fact" to understand the evidence or determine a fact in issue. The threshold issue of whether a proffered witness is qualified to testify as an expert is for the court, not the jury.(8)

Since Rule 702 provides that a witness may qualify as an expert by reason of "knowledge, skill, experience, training or education," expert witnesses are drawn from all walks of life. One may qualify as an "expert" despite the lack of an academic degree. The issue of an expert's qualifications must be resolved case by case, inasmuch as the facts of a particular case will dictate the expertise needed. The fact that a witness may qualify as an "expert" in one case does not mean he will qualify as an expert in another. It is well established that experts will not be permitted to testify in areas outside their expertise.

Historically, almost any witness who held a degree or had some experience in the subject matter at issue was permitted to testify in the form of an opinion. The rationale for liberal qualification of experts was that any flaws in the expert testimony went to the weight, not admissibility, of the testimony. As the trend toward judicial scrutiny of expert testimony increased, courts began to require "expert" witnesses to bring more to court than bare minimum credentials.

In Knight v. Otis Elevator Co.(9) a chemistengineer whose primary work involved fire safety, explosions and chemical poisoning was permitted to testify on the issue of whether...