In the Supreme Court decision, Daubert v. Merrell Dow Pharmaceuticals, Inc., 113 S.Ct. 2786 (’93), the Court tackled the important topic of “scientific evidence” but its resolution raises, without answering, important questions about evidence interpretation.
Daubert concluded that the Frye test, which limited the admissibility of novel scientific evidence to that which is generally accepted in its field, did not survive the adoption of the Federal Rules of Evidence, a conclusion flowing from the text of the Rules. In its Frye decision, Frye v. U.S., 293 F.1013 (D.C.’23) , the Supreme Court said:
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 force 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 or 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 at 1014)
Fed.R.Evid. R.702 does not state that scientific evidence is admissible only if generally accepted.
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. R.702.
The Daubert Court noted, in its opinion by Justice Blackmun, that “[n]othing in the text of this Rule  establishes ‘general acceptance’ as an absolute prerequisite to admissibility.” (Daubert at 2794) Since that Rule’s text does not contain a “general acceptance” requirement, it does not exist.
It would seem that Daubert killed Frye with a pure textual analysis, but the Court did not stop there. It also referred to the common law, the ‘liberal thrust’ of the Federal Rules, and their ‘general approach of relaxing the traditional barriers to “opinion” testimony. The Court ultimately concluded:
Given the Rules’ permissive backdrop and their inclusion of a specific rule on expert testimony that does not mention “general acceptance,” the assertion that the Rules somehow assimilated Frye is unconvincing. Frye made “general acceptance” the exclusive test for admitting expert scientific testimony. That austere standard, absent from and incompatible with the Fed.R.Evid., should not be applied in federal trials. (Id. at 2794)
The Court, then, did not seem to be relying just on the text of the Rules. The policies embodied generally in the Rules – that is, their “liberal thrust” – and the policies embedded specifically in R.702, those relaxing “traditional barriers” to expert testimony, seem influential. Since, by the Court’s analysis, text and policies coincide, it was easy to conclude that Frye should not continue to be applied. However, this approach implies that at least some of the time when policies and text do not correspond, the text should not control. If otherwise, the Court’s discussion could have begun and ended with the textual analysis.
While this portion of the Daubert opinion casts doubt on the absolute authority of plain meaning, the rest of it clearly shows the limitations of that standard. The Court, after dispatching Frye, discussed what limitations R.702 did place on the admissibility of scientific evidence, and concluded that, to be admitted, the trial judge must find scientific evidence “reliable”:
The subject of an expert’s testimony must be “scientific . . . knowledge.” The adjective “scientific” implies a grounding in the methods and procedures of science. Similarly, the word “knowledge” connotes more than subjective belief or unsupported speculation. . . . [I]n order to qualify as “scientific knowledge,” an inference or assertion must be derived by the scientific method. Proposed testimony must be supported by appropriate validation – i.e., “good grounds,” based on what is known. In short, the requirement that an expert’s testimony pertain to “scientific knowledge” establishes a standard of evidentiary reliability. (Id. at 2795)
A trial court must consequently undertake a “flexible” inquiry into whether the proffer consists of truly “scientific knowledge. . . . Many factors will bear on the inquiry,” but the trial court should consider whether the theory or technique “can be (and has been) tested [and] whether [it] has been subjected to peer review and publication. fn.37 The trial court should also consider “the known or potential rate of error . . . and the existence and maintenance of standards controlling the technique’s operation” as well as the acceptance of the theory or technique in the scientific community. (Id. at 2797)
While Daubert started this analysis with reference to the text’s use of “scientific” and “knowledge,” the plain meaning of the Rules hardly compels the resulting standard. No court-ordered framework would be compelled, since “scientific knowledge” is not a term with a determinate meaning. While perhaps it is correct to say that the enunciated framework is not inconsistent with “scientific knowledge,” the flexible guidelines are not inevitably compelled by the phrase. Many of us could not define “scientific knowledge,” and we certainly would not produce a uniform definition. The meaning of “scientific knowledge” can hardly be considered “plain.” Daubert is an illustration of the obvious point that the plain-meaning standard has to fail when a Rule does not have a plain meaning. The question then arises of how to interpret the many Rules whose text is not clear.
Daubert, however, gives no explicit guidance. The Justices enunciated no precepts on how to interpret a Rule when it is muddy. If there are methodological lessons to be learned, they must be mined from Daubert. The Court formulated its flexible framework by using a strikingly broad array of interpretive tools, not only those that might be found routinely in legal decisions such as dictionaries, lower court opinions, legal treatises, and law review articles, but also propositions asserted about science in amici briefs, books, and articles concerning the philosophy and sociology of science. fn.42 This analysis suggests that, at least when the text of a Rule is imprecise, almost any source that sheds light on the possible meaning can be used.
Chief Justice Rehnquist, in contending that the Court should go no further at this point than ruling that the Frye standard was not part of the Fed.R.Evid., discussed R.702 in conjunction with Rule 703 and commented:
The various briefs filed in this case are markedly different from typical briefs, in that large parts of them do not deal with decided cases or statutory language – the sort of material we customarily interpret. Instead, they deal with definitions of scientific knowledge, scientific method, scientific validity, and peer review – in short, matters far afield from the expertise of judges. This is not to say that such materials are not useful or even necessary in deciding how Rule 703 should be applied; but it is to say that the unusual subject matter should cause us to proceed with great caution in deciding more than we have to, because our reach can so easily exceed our grasp. (Id. at 2799)
Daubert, however, may simply be an ad hoc determination not based on any generalizable principles. The question of the admissibility of scientific opinions somehow seems different from other kinds of evidentiary decisions. As Chief Justice Rehnquist phrased it, Daubert has an “unusual subject matter”, Id., and perhaps an unusual subject matter produces a singular method of interpretation.
Considering its treatment of R.104, viewing Daubert as an ad hoc decision is a real possibility. Daubert asks who, either judge or jury, should determine that a proffered opinion is “scientific.” The Court answered that the trial court must do so under R.104(a), which means that the proponent has to establish that the proffered evidence is “scientific” by a preponderance of the evidence. (Id. at 2796) Daubert reached this conclusion without examination or citation, merely saying, “Faced with a proffer of expert scientific testimony, then, the trial judge must determine at the outset, pursuant to R.104(a), whether the expert is proposing to testify to (1) scientific knowledge that (2) will assist the trier of fact to understand or determine a fact in issue.” Id. In footnote 10, the Court quoted R.104(a) and clarified that a preponderance of proof was the appropriate standard. For anyone trying to find methodologies to resolve other evidentiary disputes, this assertion without analysis presents a problem because the admissibility of scientific evidence is not indisputably a R.104(a) question.
Huddleston v. U.S., 485 U.S.681 (’88), held that when the relevance of one piece of evidence is conditioned or dependent on the finding of another fact, R.104(b) controls. Under this provision, the trial court does not determine by a preponderance whether the foundational fact exists. Instead, the trial court merely decides whether the jury could find that it exists. If the jury could find that the fact exists, the trial court admits the disputed evidence. The Supreme Court in Huddleston reasoned that the jury must be assumed to have acted logically, and if the jury in its deliberations concludes that the preliminary fact was established, it will treat the disputed evidence as relevant and weigh it. If the jury finds that the preliminary fact was not proven, it will act logically and disregard the disputed evidence. (Id. at 690) Consequently, when confronted with other crime evidence that is relevant only if the accused actually committed the other crime, a trial court does not decide by a preponderance of proof whether the accused committed the crime. Instead, it decides whether the evidence on that issue would allow the jury to conclude that the accused committed the other crime. If the answer to that is “yes,” the evidence is admitted without the judge determining the likelihood of the accused committing the other crime.
Daubert did not explore why the Huddleston analysis does not apply to scientific evidence. Daubert maintains that a trial judge must ensure that scientific evidence “is not only relevant, but reliable. Daubert at 2795. Are relevance and reliability really two separate categories? Or is relevancy logically dependent on reliability? At least when it comes to lay witnesses, the answer is that reliability is a question of conditional relevancy.
The eyewitness report that the blue car ran the red light is relevant only if the eyewitness reliably reports what she perceived. The judge, however, does not determine by a preponderance whether the witness is reliably reporting. Instead, the jury makes that decision in its deliberations, and we trust that if they find the witness unreliable they will disregard the evidence. Scientific evidence might be the same. It is relevant only if the science is reliable. If unreliable, the jury ought to disregard it. If this contention is correct, reliability is a logical component of relevancy. Scientific reliability, then, is not a R.104(a) question which the judge determines by a preponderance of proof, but a conditional relevancy question falling within R.104(b), which authorizes the admission of scientific evidence as long as reasonable jurors could find the science to be reliable.
Justice Blackmun did not even try to explain his decision to have the judge determine that the evidence is scientifically valid before the jury can hear it. By simply asserting that it was a R.104(a) decision, he avoided discussing the conflict between his opinion and the unanimous opinion of the Court in Huddleston.
Indeed, treating scientific evidence as a conditional relevancy question would lead to the wider admission of scientific opinions consistent with the “liberal thrust” of the Rules and the lowering of traditional barriers to expert opinions, policies upon which the Court seemingly relied in striking down Frye.
Whatever the correct resolution of the R.104 issue for scientific evidence, the Court’s failure to discuss the tensions with Huddleston, the only case exploring classifications under that Rule, leaves adrift others who are trying to resolve R.104 questions. Daubert fails to advance understanding of R.104 and suggests that the Court was not interpreting R.104 with neutral, generally applicable principles, but from an ad hoc, predetermined perspective.
Daubert also fails at its most basic function of guiding trial courts in treating scientific evidence. While clearly striking down Frye, Daubert’s flexible framework is so varied in possible meaning that it hardly gives meaningful guidance on how to gauge the admissibility of scientific evidence. Instead of giving a methodology that trial courts can apply consistently in resolving questions about scientific evidence, the Court’s flexible framework has only triggered an outpouring of comments as to what the framework means or ought to mean, a sign of Daubert’s inadequacy at its most fundamental level.
For those interested in future evidentiary interpretations, Daubert fails by:
- Not making clear whether it is jettisoning a plain-meaning standard;
- Not making clear how a Rule should be interpreted when its meaning is not clear;
- Merely asserting an answer to an issue that should have been contested, the R.104 question, and;
- Formulating a flexible framework that does not truly guide lower courts.
This article was originally published on the Letric Law Library. It is an excerpt from “Text, Texts, or Ad Hoc Determinations: Interpretation of the Federal Rules of Evidence” a work by Professor Randolph Jonakait of the N.Y. Law School.