Federal Rule of Evidence 702: A Useful Rule (When It's Followed)

Sep 09, 2021

When it comes to evidentiary disputes, it can be tough to predict how a particular judge will rule. What is inadmissible character evidence (Rule 404(a)) to one judge might be admissible "other acts" evidence (Rule 404(b)) to another.

And when it comes to expert opinion testimony, there can be even more uncertainty. A judge considering a shaky opinion might—citing the Supreme Court's landmark ruling, Daubert v. Merrell Dow Pharmaceuticals, Inc.—exclude the opinion on the ground that it is fulfilling its gatekeeping role to "ensure that any and all scientific testimony or evidence admitted is not only relevant, but reliable." 509 U.S. 579, 589 (1993). Another judge, likewise citing Daubert, might admit the opinion because "[v]igorous cross-examination, presentation of contrary evidence, and careful instruction on the burden of proof are the traditional and appropriate means of attacking shaky but admissible evidence." Id. at 596 (emphasis added).    

Rule 702 was amended in 2000 so that it reflected the holding of Daubert and its progeny (e.g.General Electric v. Joiner, 522 U.S. 136 (1997), Kumho Tire v. Carmichael, 526 U.S. 137 (1999)). The amended Rule 702 is a simple read. It says, in essence, a qualified expert may provide opinion testimony if a checklist of conditions is met. But since the 2000 amendment, some courts have ignored Rule 702's requirements and read into the rule a presumption of admissibility. This has resulted in too many juries hearing opinions that amount to little more than, "I'm an expert, therefore I'm right." 

To find order in the chaos, practitioners should acquaint themselves with the requirements of Rule 702 whenever they are the proponent (or opponent) of expert opinion testimony. Knowing and applying the specific requirements of the rule can give attorneys the best chance to tackle any admissibility challenges.   

A Little History: Daubert + Rule 702 = No More "General Acceptance" Requirement

Let's start in 1993 with the Daubert ruling. In Daubert, the petitioners were minor children, Jason Daubert and Eric Schuller, who were born with serious birth defects. They and their parents sued Merrell Dow Pharmaceuticals, Inc. ("Merrell") in California state court alleging that their mothers' ingestion of Bendectin (a prescription antinausea drug made by Merrell) caused their birth defects. Id. at 582. 

Merrell removed the cases to federal court and moved for summary judgment. In support of its motion, Merrell included a declaration from an expert who opined that, based on all relevant literature, no study found that Bendectin was capable of causing malformations in fetuses. Id. The petitioners' opposition included competing opinions from expert witnesses who concluded (1) animal studies found a link between Bendectin and malformations; (2) pharmacological studies of the chemical structure of Bendectin showed similarities between Bendectin and other substances known to cause birth defects; and (3) the "reanalysis" of previously published epidemiological (human statistical) studies. Id. at 583. 

The trial court granted summary judgment because the petitioners' expert witness opinions failed to meet the then-required standard that scientific evidence be "general[ly] accept[ed] in the field to which it belongs" to be admissible. Id. The Ninth Circuit affirmed summary judgment, citing the "general acceptance" standard found in Frye v. United States, 54 App. D.C. 46 (1923). The Supreme Court granted review "in light of sharp divisions among the courts regarding the proper standard for admission of expert testimony." Id. at 585. 

The Court held that the Frye test was superseded by the adoption of the Federal Rules of Evidence. Id. at 587. Federal Rule of Evidence 702, governing expert testimony, provided—in 1993—as follows: "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 Court first noted that "[n]othing in the text of ... Rule [702] establishes 'general acceptance' as an absolute prerequisite to admissibility." Id. at 588. The Court cited the drafting history, which revealed a desire to loosen certain barriers for expert testimony:

The drafting history makes no mention of Frye, and a rigid "general acceptance" requirement would be at odds with the "liberal thrust" of the Federal Rules and their "general approach of relaxing the traditional barriers to 'opinion' testimony." 

Id. at 588, citing Beech Aircraft Corp. v. Rainey, 488 U.S. 153, 169 (1988). 

Accordingly, the Court found that the Frye standard was "absent from, and incompatible with, the Federal Rules of Evidence, [and thus] should not be applied in federal trials."  509 U.S. at 589. That did not mean, however, that the Court simply left trial courts to follow Rule 702 without any guidance. Instead, the Court laid out the framework in which courts should apply the rule. 

First, the Court explained that the analysis begins with Rule 104(a). Rule 104(a) deals with preliminary questions, such as whether evidence is admissible, and it states as follows: "The court must decide any preliminary question about whether a witness is qualified, a privilege exists, or evidence is admissible. In so deciding, the court is not bound by evidence rules, except those on privilege." The preliminary questions trial courts must analyze under Rule 104(a) are "whether the expert is proposing to testify to (1) scientific knowledge that (2) will assist the trial of fact to understand or determine a fact in issue." Id. at 592. The proponent of the expert opinion testimony must establish these Rule 104(a) questions by a "preponderance of proof." Id., n. 10, citing Bourjaily v. United States, 483 U.S. 171, 175 - 176 (1987). 

Second, without setting out a "definitive checklist or test[,]" the Court identified worthwhile considerations when analyzing scientific opinion testimony:

  1. Whether the theory or technique can be (and has been) tested;
  2. Whether the theory or technique has been subjected to peer review and publication; 
  3. Whether there is a known or potential rate of error of the particular technique or theory; 
  4. Whether the theory or technique is "generally accept[ed." 

Id. at 593 - 594. 

These factors, the Court explained, were intended to provide trial courts with a "flexible" approach to determine "scientific validity and thus the evidentiary relevance and reliability" of expert opinion evidence. Id. at 594 - 595. 

2000 Amendment to Rule 702: Intended Alignment With Daubert 

Rule 702 was amended in response to Daubert. Advisory Committee Note to 2000 Amendments to Rule 702. Following Daubert, courts were inconsistent in applying Daubert's requirements. As explained by the Advisory Committee:

Some courts approach Daubert as a rigorous exercise requiring the trial court to scrutinize in detail the expert's basis, methods, and application. Other courts hold that Daubert requires only that the trial court assure itself that the expert's opinion is something more than unfounded speculation. 

Hon. Fern M. Smith, Report of the Advisory Committee on Evidence Rules (May 1, 1999) at 7, in Advisory Committee on Evidence Rules October 1999 Agenda Book 52 (1999).

To provide a "uniform structure for assessing expert testimony," the Advisory Committee sought to reform Rule 702. And while the framework stated in Daubert was the intended standard, challenges remained because of the ruling's mixed messages. Daubert directed trial courts to make "a preliminary assessment of whether the reasoning or methodology underlying the testimony is scientifically valid and of whether that reasoning or methodology properly can be applied to the facts in issue." Daubert, 509 at 592 - 593. At the same time, Daubert maintained that "[v]igorous cross-examination, presentation of contrary evidence, and careful instruction on the burden of proof are the traditional and appropriate means of attacking shaky but admissible evidence." Id. at 596.

To reconcile these (ostensibly) competing approaches, the Advisory Committee recognized that cross-examination is often insufficient to combat the undue influence of experts peddling junk science or theories:

The premise [in Daubert] is that cross-examination cannot undo the damage that has been done by the expert who has power over the jury. This is because, for the very reason that an expert is needed (because lay jurors need assistance) the jury may well be unable to figure out whether the expert is providing real information or junk. 

Memorandum from Daniel J. Capra, Advisory Comm. on Evidence Rules, to Advisory Comm. on Evidence Rules, Possible Amendment to Rule 702 (Oct. 1, 2019) at 11 in Advisory Committee on Evidence Rules October 2019 Agenda Book 131 (2019). 

Accordingly, Rule 702 was amended with an eye toward "a more rigorous and structured approach than some courts [were] currently employing." May 1, 1999 Report of the Advisory Committee on Evidence Rules at 7. The amended Rule 702 provides as follows:  

A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if:

(a) the expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue;

(b) the testimony is based on sufficient facts or data;

(c) the testimony is the product of reliable principles and methods; and

(d) the expert has reliably applied the principles and methods to the facts of the case.

Trial courts are thus required to consider the admissibility of expert testimony with "exacting" scrutiny. Weisgram v. Marley Co., 528 U.S. 440, 455 (2000) ("Since Daubert ... parties relying on expert evidence have had notice of the exacting standards of reliability such evidence must meet.").  

Post-2000: Ignoring Rule 702's Requirements 

Since the passage of Rule 702's amendment, some courts have bungled its application. For example, both the Supreme Court in Bourjailysupra, and the Advisory Committee Notes make clear that the proponent of expert testimony bears the burden of demonstrating the admissibility requirements of Rule 702. And yet, courts have incorrectly assumed that this burden occurs on a tilted scale. One district court has remarked as follows: 

The party seeking to introduce the expert testimony bears the burden of establishing by a preponderance of the evidence that the proffered testimony is admissible. There is a presumption that expert testimony is admissible.

S.E.C. v. Yorkville Advisors, LLC, 305 F. Supp. 3d 486, 503 - 04 (S.D.N.Y. 2018). 

The court was half right. Nowhere in Rule 702 (or 104(a)) is there any mention that expert testimony is presumptively admissible. This error has been recycled and repeated by several courts. The usual source cited for this proposition is Borawick v. Shay, 68 F. 3d 597, 610 (2d Cir. 1995), cert denied, 517 U.S. 1229 (1996). But Borawick did not even address Daubert (and it predates the 2000 amendment to Rule 702): "We do not believe that Daubert is directly applicable to the issue here." Later in the opinion, however, it offered the following comment in dicta: "[B]y loosening the strictures on scientific evidence set by FryeDaubert reinforces the idea that there should be a presumption of admissibility of evidence." 

Result: Junk Science Too Often Admitted

When courts fail to properly consider the required elements of Rule 702, the admission of expert testimony can become too much of a free for all. The advent of psychologists in employment cases opining on "social framework" evidence is one example. "Social framework" evidence has been described as the "general processes of behavior or general causation principles." John Monahan et al., Contextual Evidence of Gender Discrimination, 94 Va. L. Rev. 1715, 1726 (November 2008). These experts look to relay "general conclusions from social science research to help determine specific factual issues in a case." Id.  But what about Rule 702? Rule 702(d) requires that "the expert ... reliably appl[y] the principles and methods to the facts of the case." 

In Tuli v. Brigham & Women's Hospital, Inc., 592 F. Supp. 2d 208 (D. Mass. 2009), the court considered a motion to exclude "an expert in social framework analysis, which specifically addresses issues of sex stereotyping and discrimination." The expert admitted that he did not "determine whether or not any particular comment or act was determined by the operation of stereotypes." Id. at 214. Put another way, the expert wanted to simply explain that gender stereotyping and bias exists and—without applying any methodology or principles to the facts of the case—"opine on whether the allegations in the case at bar are consistent with [discrimination]." Id. at 216. To be sure, the expert readily admitted that his opinions made no attempt to comply with Rule 702(d): 

This report represents social framework testimony that ... is not the same as performing diagnostic tests of specific individuals who may have discriminated against [plaintiff] or a systematic investigation into the social climate at [plaintiff's former employer]. While one could attempt to perform such tests, their scientific integrity would be fatally compromised when conducted within the context of a lawsuit against those individuals or the corporation that employs them.

Id. at 214.

By disavowing any attempted compliance with Rule 702(d), exclusion should have been fairly obvious. After all, other courts had excluded such evidence on the simple fact that jurors do not need "experts" to explain what gender stereotyping is. See e.g.Ray v. Miller Meester Advertising, Inc., 664 N.W. 2d 355 (Minn. Ct. App. 2003) ("Information about and commentary on gender issues is so abundant in our society that it has become a common stereotype that women receive disparate and often unfairly discriminatory treatment in the workplace.”). But instead of acknowledging the requirements of Rule 702, the court essentially took a "sounds good to me" approach to the question of admissibility. 

[D]efendants argue that only testimony pointing to the facts of this case will assist the jury and that nothing else fulfills the bedrock requirements of Rule 702. As indicated above, I find just the opposite. [Plaintiff's expert] brings the insights of established scientific inquiry and social framework analysis, as to which he is an expert, to bear on the facts of this case.

Id. at 215.

The problem with the court's remarks is that by ignoring Rule 702, it failed to consider how fatal the expert's admission was that there was zero way for him to apply his opinions about stereotypes in general to the facts of the case: "[The expert] indicates that such an opinion is for the decisionmakers in this case, namely the jury, and that it is not possible to make any decision to a reasonable degree of scientific certainty about a real world case." Id. at 214. 

Rule 702: Another Revision Needed? 

With opinions like the one in Tuni getting a pass by courts because of their failure to adhere to Rule 702, the Advisory Committee on the Civil Rules of the Federal Judicial Conference have recently approved a proposed amendment to Rule 702, as follows:   

A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if the court finds that  the proponent has demonstrated by a preponderance of the evidence that:

(a) the expert’s witness’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue;

(b) the testimony is based on sufficient facts or data;

(c) the testimony is the product of reliable principles and methods; and

(d) the expert witness’s has reliably applied expert’s opinion reflects a reliable application of the principles and methods to the facts of the case.

The first change simply reflects what the law is (but is not always being applied)i.e., that the proponent of the expert opinion bears the burden by a preponderance of the evidence to establish the requirements of Rule 702. See Bourjaily, 483 U.S. at 175 - 176. In addition, the proposed language in subdivision (d), according to the Draft Committee Notes, was amended "to emphasize that the trial judge must exercise gatekeeping authority with respect to the opinion ultimately expressed by a testifying expert.  A testifying expert’s opinion must stay within the bounds of what can be concluded by a reliable application of the expert’s basis and methodology." Moreover, the Draft Committee Notes also emphasize that the amendments are to reflect the current law, not propose anything new:    

Nothing in the amendment imposes any new, specific procedures.  Rather, the amendment is simply intended to clarify that Rule 104(a)’s requirement that a court must determine admissibility by a preponderance applies to expert opinions under Rule 702.  Similarly, nothing in the amendment requires the court to nitpick an expert’s opinion in order to reach a perfect expression of what the basis and methodology can support.  The Rule 104(a) standard does not require perfection.  On the other hand, it does not permit the expert to make extravagant claims that are unsupported by the expert’s basis and methodology.


Will Rule 702 ultimately be amended? Who knows, but regardless, familiarity with the specific requirements of the rule (amended or otherwise) give practitioners the best chance to successfully offer (or oppose) expert witness testimony. 

David Sugden is a shareholder at Call & Jensen in Newport Beach, California.

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