Evidentiary Standard For Reliability Of Novel Expert Proof
Since the early part of this century, the federal courts have attempted to limit the uncertainty surrounding novel scientific evidence by establishing an evidentiary standard of reliability for scientific proof. Frye v. U.S., 293 F. 1013 (D.C.Cir.'23), provided the standard that governed the introduction of expert evidence for more than half a century. The courts have also embraced procedures, including various forms of discovery providing for mandatory disclosure of witnesses "who may be used at trial to present evidence under Rules 702, 703, or 705," and requiring submission of written reports by expert witnesses, which give the parties and the courts greater opportunities to test the reliability of novel expert testimony.
The standard of reliability for expert testimony and the applicable procedures in federal courts in the years proceeding the landmark 1993 Daubert case had undergone significant change.
A. Frye v. U.S.
As Judge Learned Hand in "Historical and Practical Considerations Regarding Expert Testimony", 15 Harv.L.Rev. 40 (1901-02) observed at the beginning of this century, expert evidence must be reliable in order to have some "possible weight" on an issue and be admitted for consideration by a trier of fact. Absent reliability, the evidence would not be relevant to the inquiry. In Frye, the Court of Appeals considered an appeal from a trial court's refusal to admit the resultsof a test based on systolic blood pressure, offered to prove the truthfulness of a defendant in a murder prosecution. In an oft-quoted passage, the court crafted a standard to determine whether scientific evidence was sufficiently reliable to warrant consideration by a trier of fact:
Just when a scientific principle or discovery crosses the line between the experimental and demonstrable stages is difficult to define. Somewhere in this twilight zone the evidential forces of the principle must be recognized, and while courts will go a long way in admitting expert testimony deduced from a well-recognized scientific principle of discovery, the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs.
Frye contemplated two stages for acceptance of new science. First, the scientific community develops a theory and determines its reliability using scientific method. This stage required experimentation with the new science's methodology and publication of the results for scrutiny and approval by the scientific community. Second, once the new science became "demonstrable," based on acceptance in the scientific community, the court could permit its use as evidence in the courtroom. Without explanation, the court of appeals chose "general acceptance" in the relevant scientific community as the standard for governing the admission of novel scientific evidence.
Under Frye, the party proffering novel scientific evidence must show general acceptance by offering scientific publications, judicial decisions, evidence of practical use, or testimony by scientists on their peers' position regarding the evidence in question. Many courts, faced with determining the admissibility of a wide array of scientific evidence, favored the Frye standard. Often, new scientific evidence failed to survive this demanding standard. For example, McCormick on Evidence reports:
Polygraphy, graphology, hypnotic and drug induced testimony, voice stress analysis, voice spectrograms, ion microprobe mass spectroscopy, infrared sensing of aircraft, retesting of breath samples for alcohol content, psychological profiles of battered women, and child abusers, post traumatic stress disorder as indicating rape, astronomical calculations, and blood group typing, all have fallen prey to [Frye's] influence.
Many rationales have been offered to support the use of the Frye standard as a means of excluding evidence. The justifications included: that the standard guaranteed a minimum number of knowledgeable experts; that it promoted uniformity of decisions; that it eliminated the need for time consuming hearings on admissibility; and, most importantly, that it assured a method by which those best qualified to assess the validity of scientific evidence would effectively determine its admissibility.
The general acceptance test of Frye became the "dominant standard for determining the admissibility of novel scientific evidence at trial." Indeed, Professor Clark's testimony in Briggs that the doll tests were "generally accepted as indications of the child's sensitivity to race as a problem" was calculated to satisfy Frye. Nonetheless, as Justice Blackmun noted in Daubert, the merits and application of Frye were extensively debated by commentators. Professor McCormick was one of the primary critics of Frye prior to the adoption of the Federal Rules of Evidence. In 1972, he wrote:
"General scientific acceptance" is a proper condition for taking judicial notice of scientific facts, but not a criterion for the admissibility of scientific evidence. Any relevant conclusions which are supported by a qualified expert witness should be received unless there are other reasons for exclusion. Particularly, probative value may be overborne by the familiar dangers of prejudicing or misleading the jury . . . . If the courts used this approach, instead of repeating a supposed requirement of "general acceptance" not elsewhere imposed, they would arrive at a practical way of utilizing the results of scientific advances. Charles T. McCormick, Evidence Sec. 203, at 491 (2d ed.'72)
B. Federal Rule Of Evidence 702
The Fed.R.Evid., effective July 1, 1975, provided the first modern and uniform set of evidence rules for the trial of civil and criminal cases in the federal courts. Rule 702, which governs the admission of expert testimony, does so in terms that do not expressly address reliability:
If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise.
The Advisory Committee on Evidence, appointed by the Supreme Court, formulated the language which Congress adopted as Rule 702. Rule 702 and the accompanying Advisory Committee Note echo McCormick's criticism of Frye. Reliability should depend on relevance rather than the general acceptance of scientific evidence. Fed.R.Evid. 401 defines "relevant evidence" as "evidence having any tendency to make the existence of any fact that is of consequence to the determination of the action more probable or less probable than it would be without the evidence.". Rule 403 provides that 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 considerations of undue delay, waste of time, or needless presentation of cumulative evidence." Rule 702 incorporates a relevancy requirement by permitting the introduction of scientific evidence which "will assist the trier of fact to understand the evidence or to determine a fact in issue." Surprisingly, the Advisory Committee Note made no mention of Frye. Instead, the Committee quoted Professor Mason Ladd:
There 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 fromthose having a specialized understanding of the subject involved in the dispute. Mason Ladd, Expert Testimony, 5 Vand.L.Rev.414 ('52)
Thus, Rule 702 contemplated the admission of expert testimony that was relevant in the sense that such testimony would facilitate an understanding of scientific, technical, or other specialized facts to determine an issue.
Nonetheless, when called on to apply Rule 702, the majority of federal courts continued to utilize Frye. The courts were understandably reluctant to accept the sub silentio overruling of a precedent of Frye's stature, and often incorporated the general acceptance standard into the relevance determination under Rule 702.
A number of courts have gradually begun to abandon the general acceptance standard. In 1975, the Fourth Circuit affirmed the admission of a voice spectrogram analysis of telephoned bomb threats. The court found Professor McCormick's critique of Frye persuasive:
Unless an exaggerated popular opinion of the accuracy of a particular technique makes its use prejudicial or likely to mislead the jury, it is better to admit relevant scientific evidence in the same manner as other expert testimony and allow its weight to be attacked by cross-examination and refutation. U.S. v. Baller, 519 F.2d 463 (4th Cir.)
This decision required only that scientific evidence be supported by a "demonstrable, objective procedure" rather than general acceptance. Three years later, the 2nd Circuit approved the admission of similar evidence in a prosecution on narcotics charges in U.S. v. Williams, 583 F.2d 1194 (2d Cir.'78). The considerations governing admissibility, the court wrote, were the "probativeness, materiality, and reliability of the evidence." In addition, the court of appeals directed the district court to consider whether the evidence had "any tendency to mislead, prejudice, or confuse the jury."
In 1985, the 3rd Circuit decided U.S. v. Downing, 753 F.2d 1224 (3d Cir.'85), the most significant precursor to Daubert. In Downing, the court considered the admissibility of expert testimony concerning the reliability of eyewitness identification. The court concluded that the language and spirit of the Fed.R. Evid., in addition to the experience of the courts in attempting to apply Frye, suggested that an approach more flexible than the general acceptance test for the admissibility of novel scientific evidence was appropriate. Downing instructed the district courts to undertake a preliminary inquiry as to the soundness of the theory or technique on which proffered scientific evidence was based. This inquiry was to include consideration of the risk that the jury would be overwhelmed, confused or misled and assessment of the materiality of the evidence to the issue in dispute.
The Third Circuit envisioned a multi-factored analysis of the reliability of the evidence. The court permitted, but did not require, the identification of a relevant scientific community and a determination of the degree of acceptance within that community. In language reminiscent of Frye, the court suggested that in many cases, the general acceptance factor was likely to be decisive. Additional factors that district courts could consider included the novelty of the technique and its relationship to established modes of scientific analysis, the existence of specialized literature dealing with the technique, the likelihood that the scientific basis of the new technique has been exposed to critical scientific scrutiny, the qualifications and professional stature of the expert witness, and the potential and actual non-judicial uses of the scientific technique.
According to Downing, district courts should also focus on the risk of error, both the frequency with which the method leads to erroneous results and the type of error generated by the technique. Finally, the district courts should consider whether the expert testimony had been offered in earlier cases to support or dispute the merits of a particular procedure. The Downing opinion noted that "other factors could be added to the list." The Third Circuit's articulation of a clear alternative to Frye set the stage for the Supreme Court's resolution in Daubert of the conflict among the circuits over the appropriate standard of reliability for scientific evidence under Rule 702.
C. Assessment Of Reliability Of Scientific Evidence Prior To Daubert
The cases decided after the adoption of Rule 702, but prior to Daubert, reflected the different approaches of the courts described in the preceding section. Occasionally, courts would restate and apply the Frye general acceptance test. Some courts adopted a hybrid approach that incorporated the general acceptance standard into the determination of relevance under Fed.R.Evid. 702. Still other courts jettisoned Frye and attempted to assess for themselves the reliability of scientific evidence.
Dang Vang v. Vang Xiong X. Toyed, 944 F.2d 476 (9th Cir.'91), illustrates the first approach. Female Hmong refugees from Laos brought an action pursuant to 42 U.S.C. 1983 against an employee of a Washington State Employment Security office who allegedly raped them when they contacted him about obtaining employment. The district court allowed extensive anthropological testimony, including a general explanation of Hmong culture, the longterm reliance of the Hmong on governmental agencies for support, and the role of women in that culture. The court found such testimony to be both relevant and necessary because it assisted the jury in understanding certain behavior of parties that might otherwise be confusing, such as the plaintiffs' continued contact with the defendant after a rape. The court excluded opinion testimony regarding the specifics of the case, such as whether there was a rape and why these particular plaintiffs did not report the rape. On appeal, the defendant maintained that all of the expert testimony should have been excluded because it failed to satisfy the requirements of Frye. The 9th Circuit did not question appellant's citation to Frye. Instead, the court rejected the argument as inapposite because the testimony below derived from anthropological study of the Hmong, rather than a novel scientific theory, and therefore should not be scrutinized under Frye.
U.S. v. Kozminski, 821 F.2d 1186 (6th Cir. 1987) (en banc), aff'd, 487 U.S. 931 (1988), exemplifies the hybrid approach, where the court incorporates the Frye standard into the relevance determination under Rule 702. Kozminski was an appeal from a criminal conviction for violation of civil rights. Appellants, a dairy farmer and his wife, were convicted of willfully holding two retarded farm workers in involuntary servitude and of conspiring to deprive the workers of their constitutional right to be free from involuntary servitude154 as guaranteed by the Thirteenth Amendment. The couple's son was also convicted on the conspiracy charge. The Kozminskis argued on appeal that the district court erred in admitting expert psychological testimony to show that the two victims were detained against their will. A psychologist testified that the victims' limited mental ability, combined with the psychological pressures exerted on them by the conditions at the dairy farm, created an "involuntary conversion" to complete dependency. The 6th Circuit, sitting en banc, held that the district court improperly admitted this evidence. The court explained: "For expert testimony to be admissible under Rule 702, a fourpart test must be met: (1) a qualified expert; (2) testifying on a proper subject; (3) in conformity to a generally accepted explanatory theory; (4) the probative value of which outweighs any prejudicial effect."
According to the 6th Circuit, the only arguably relevant theory shown to have general acceptance by the trial testimony was the "captivity syndrome" associated with the brainwashing of prisoners of war. The appellate court was not satisfied that any established theory existed to support a conclusion that the Kozminskis' actions resulted in complete dependency on the part of the victims: "As bad as conditions on the Kozminski's dairy farm are alleged to be, they fall short of those found in a Chinese prison camp. Accordingly, captivity syndrome is inapplicable as a matter of law given the facts of this case." Because Frye's requirement of a generally accepted explanatory theory was not met, the court held the testimony inadmissible under Rule 702.
A concurring opinion in Kozminski cited Frye and emphasized the need to protect a defendant in a criminal case against scientific evidence which may bear an "aura of special reliability and trustworthiness," even when it is based on an unproved hypothesis which has yet to obtain any degree of acceptance in its field. Id. at 1199 (Krupansky, J., concurring). A dissenting opinion urged that the Frye test should not be applicable to the testimony because it was properly categorized as "other specialized" rather than "scientific" knowledge under Rule 702, and as such, could be based on a subjective assessment of the victims and their conditions of confinement. Id. at 1215 (Guy, J., dissenting). The dissent, noting the abandonment of Frye by the Second and Third Circuits, also argued that the majority's concern with the reliability of the expert testimony could be better addressed under Rule 403, which permits the exclusion of relevant evidence if its probative value is substantially outweighed, inter alia, by the danger of unfair prejudice, confusion of the issues, or misleading the jury. Id. at 1214.
Spencer v. General Elec., 688 F. Supp.1072 (E.D.Va.'88), typifies the third approach mentioned above, where the court attempts its own assessment of the scientific reliability of proffered expert testimony. Spencer involved a Title VII sexual harassment claim and state tort claims against a former supervisor and employer brought by an employee claiming to be a victim of rape and other sexual misconduct. At trial, the plaintiff attempted to introduce the testimony of a forensic psychiatrist that plaintiff suffered from Post Traumatic Stress Disorder (PTSD) as proof that the rape actually occurred.
Ultimately, the district court held the testimony inadmissible for this purpose. Noting that PTSD is a condition recognized in psychiatry as the emotional reaction to traumatic events, such as rape, the court cited the American Psychiatric Assn., Diagnostic and Statistical Manual of Mental Disorders for the proposition that PTSD may be caused by a variety of traumatic events outside the range of common experiences, such as military combat, bombing, torture, airplane crashes, or rape. In the case of rape, the condition is sometimes labeled Rape Trauma Syndrome (RTS).
The court concluded, however, that evidence of PTSD or RTS was not a scientifically reliable means of proving that a rape occurred: "Evidence of PTSD occasioned by rape" . . . "is not a scientifically reliable means of proving that a rape occurred. PTSD is simply a diagnostic category created by psychiatrists; it is a human construct, an artificial classification of certain behavioral patterns. RTS was developed by rape counselors as a therapeutic tool to help identify, predict, and treat emotional problems experienced by the counselor's clients or patients. It was not developed or devised as a tool for ferreting out the truth in cases where it is hotly disputed whether the rape occurred. Unlike fingerprints, blood tests, and lie detector tests, RTS was not devised to determine the 'truth' or accuracy of a particular past event--i.e., whether, in fact, a rape in the legal sense occurred." . . . "The scientific evaluation of rape trauma syndrome has not reached a level of reliability that surpasses the quality of common sense evaluation present in jury deliberations."
While the district court made its own determination of the reliability of the proffered evidence, its opinion did not completely ignore Frye. The court questioned several authorities which had admitted PTSD or RTS evidence under the Frye test based on findings that the disorders were "generally accepted to be a common reaction to sexual assault." The court opined that the relevant issue was not whether rape victims may display certain symptoms, but whether diagnosis of PTSD or RTS provided scientifically reliable proof that an alleged victim was raped. Thus, the court believed that, under Frye, the evidence should not be admitted for this purpose. After trial, the district court held that the employee failed to prove by a preponderance of evidence that the alleged sexual assaults and rape took place. The evidence issue was not raised on appeal, and the 4th Circuit affirmed. Spencer v. General Elec, supra.
The court's exclusion of the psychiatric evidence of PTSD to corroborate the plaintiff's testimony that she was raped, on grounds that such evidence was irrelevant, seems questionable. The diagnosis of the plaintiff with a disorder that experts recognize as affecting persons who have suffered significant trauma subsequent to the date of the alleged incident was relevant because it tended to support her testimony that she had indeed been raped. Such evidence is relevant even if the diagnosis standing alone did not show the cause of the condition. The court's evidentiary ruling in Spencer has not been cited by any other federal court. Nonetheless, the decision illustrates the types of issues which a court following the third line of authority must address in an effort to determine for itself the reliability of scientific proof in a federal civil action.
* The above material was excerpted, modified and otherwise prepared by the 'Lectric Law Library from "Novel Expert Evidence In Federal Civil Rights Litigation" a work by Gordon J. Beggs, Fair Employment Practices
Clinic, Cleveland-Marshall College of Law. Gordon Beggs. The original was found at www.wcl.american.edu
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