Tuesday, September 3, 2013

Expert Admissibility: Frye & the Daubert Trilogy

In the United States justice system, two standards primarily govern the admissibility of expert testimony: Frye and Daubert. Experts are expected to know what standard the court is using to determine the admissibility of expert testimony. If the case is in Federal Court, then the Daubert standard always applies. But in state court it varies. Most states have adopted Daubert (41 as of July 2013), with the remaining governed by Frye. Here we present a brief history of the key cases affecting the admission of expert testimony and what those decisions mean for experts.

What is Frye?

The Frye standard means expert testimony is admissible if the underlying scientific principles have gained general acceptance within the relevant scientific community. This standard originated in Frye v. United States, in which the lower court in 1923 ruled that the polygraph test could not be used in court because it had not received general acceptance among the scientific community. The court excluded the expert testimony relying on the polygraph results and the defendant, James Alphonzo Frye, was convicted of second degree murder. The appellate court upheld the Washington D.C. court ruling, and affirmed the conviction (Frye v. United States, 293 F. 1013, D.D. Cir. 1923). This appellate court ruling became the standard governing admissibility of expert testimony in Federal criminal courts but did not find its way into Federal civil courts until the 1980s. 

What Does Frye Mean for Experts?

The Frye test for admissibility of expert testimony requires experts to both demonstrate expertise in their specific field of science and that their methods and theories used to support their opinions are generally accepted. The first factor is established through education, experience, and recognition as contributing to the relevant field of science. The second factor is demonstrated through peer-reviewed literature, and/or other scientific forums showing consensus by the scientific community on the underlying science and methods used to support the expert opinions. Though Frye helps judges decide "both who is an expert and what expert testimony is admissible" (Matson, 2013), its major downside is that an expert may be eminently qualified in the relevant field, but that expert’s testimony cannot be admitted if it is based on emerging sound science that has not yet achieved general acceptance.

What is Daubert?

The Federal Daubert standard (pronounced dow-burt) means expert testimony does not need to meet the general acceptance standard to be admissible as long as the underlying methodology is shown to be relevant and reliable. This standard was defined by the Supreme Court in 1993 in its landmark decision in Daubert v. Merrell Dow Pharmaceuticals, Inc., a case concerning alleged birth defects from the drug Bendectin taken during pregnancy. At issue was whether the plaintiff’s evidence linking Bendectin to birth defects could be admitted in court when the methodologies underlying the experts’ testimony had not gained general acceptance within the scientific community. The Supreme Court unanimously decided that the Frye test had been superseded when the Federal Rules of Evidence were updated and adopted in 1975, and therefore, the general acceptance standard should not have been applied by the lower court (Daubert v. Merrell Dow Pharm. 509 U.S. 579, 1993). In 1975, Federal Rule of Evidence 702 stated (Fed. R. Evid. 702):

If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or 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.

In brief, Rule 702 is a relevance and reliability standard.  It allows for the introduction of novel, sound science if it can be shown to be reliable, scientifically valid and will assist the jury (the trier of fact). The Supreme Court also held that Rule 702’s gatekeeping function of judges to determine whether expert testimony is admissible was to be strengthened. To assist with that determination, the Court outlined four factors or criteria to be considered when evaluating expert testimony (509 U.S. 579, 1993): 
  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 the theory or technique has a known or potential error rate; 
  4. Whether the theory or technique has general acceptance within a relevant scientific community.

The Supreme Court remanded the case to the U.S. Court of Appeals for the 9th Circuit, the court that had originally affirmed the lower court’s decision to grant summary judgment for the defendant (Merrell Dow) upon excluding plaintiff’s expert testimony under the Frye test. On remand, the 9th Circuit reconsidered plaintiff’s evidence using the new Daubert guidelines and again excluded plaintiff’s experts’ testimony. The court found that the testimony was not derived from the scientific method, was not based on independent research, peer-reviewed literature, or an adequately explained methodology, and  was insufficient to establish causation, and consequently inadmissible. Upon excluding plaintiff’s experts, the 9th Circuit granted summary judgment for the defendant (43 F.3d 1311; 1995). 

What Does Daubert Mean for Experts?

Under Daubert, judges determine if an expert is qualified in the relevant field (same as in Frye) before determining the relevance and reliability of the science. In the twenty years since Daubert, judges in federal and state courts have shown broad latitude on how they interpret and apply the Daubert criteria to expert testimony. Some judges rigidly require experts to meet all four factors, whereas other judges consider the factors to be independent of one another and make a determination as to which factors, if any, to apply. Whether in a Federal or a state court, experts may anticipate a Daubert challenge to exclude their testimony prior to trial. Therefore, it is incumbent on experts not only to demonstrate they are qualified to testify in the specific field based on their education, experience and training , but most importantly to demonstrate how the underlying methodology they employed to arrive at their expert opinions satisfies the factors listed above. 

Beyond Daubert 

The Daubert Trilogy refers to the three key cases that established precedence for how judges determine the admissibility of expert testimony.  Joiner and Kumho are the two additional Supreme Court cases, decided within a few years of Daubert.

General Electric v. Joiner

In 1997, the Supreme Court heard General Electric v. Joiner, a toxic tort case concerning lung cancer from exposure to polychlorinated biphenyls (PCBs). At issue was the question of the proper standard of review for the admissibility of evidence as it related to excluding expert testimony when the outcome was summary judgment, not a trial. The District Court had granted summary judgment for General Electric as a result of excluding plaintiff’s expert testimony. The court ruled that the expert failed to demonstrate how the data sufficiently supported his conclusion that Mr. Joiner’s lung cancer was caused by PCBs.
The Court of Appeals for the 11th Circuit reversed, arguing the trial court should be held to a different standard when considering the admission of testimony during a summary judgment ruling. The 11th Circuit also indicated that the trial court usurped the role of the jury when it weighed the evidence instead of the trier of fact (the jury). The Supreme Court reversed and held that trial court judges should not be held to a different standard when deciding on admissibility of evidence, including expert testimony, even when the result is summary judgment. The “abuse of discretion” standard is the correct one for an appellate court to use when it reviews a trial court judge’s decision on such matters. Furthermore, the Supreme Court decided the trial court judge had not abused its discretion by excluding the expert’s testimony and agreed with the District Court’s ruling on summary judgment. (118 S. Ct. 512, 1997)

A key aspect of the Supreme Court’s decision affecting experts is the phrase “analytical gap” coined by Chief Justice Rehnquist in the majority opinion. This phrase is used in Daubert motions to exclude expert testimony when one party argues the gap between the data relied upon and the opinion being proffered is too great.

What Does Joiner Mean For Experts?

The Supreme Court’s ruling in Joiner affirmed the role of judges as gatekeepers to ensure expert testimony is both relevant and reliable to be admissible. It also requires judges to have a deeper understanding of the scientific issues in order to determine if an expert’s conclusions are sufficiently supported by the underlying methodology and data. Joiner requires experts to demonstrate their conclusions are derived from a reliable methodology rooted in scientific principles. This is normally accomplished in a detailed expert report. An expert will not survive a Daubert challenge if he/she purports that his/her opinions make sense solely because he/she is an expert in that field, and/or presents what can be effectively characterized by the opposing side and accepted by the trial judge as inadequate supportive data.

Kumho v. Carmichael 

In 1998, the Supreme Court heard Kumho Tire Co. v. Carmichael, a case concerning the cause of a rear tire blowout on a minivan that overturned killing one passenger and injuring seven others. At issue was whether Daubert applied to experts other than scientists. In this case, the plaintiffs’ expert, a tire failure analyst, opined that the blowout that caused the accident was a result of a manufacturing and/or design defect in the tire. His conclusion was supported by a visible and tactile inspection of the failed tire, and his determination that there had not been tire abuse by the owner of the vehicle.  The District Court, relying on the Daubert standard to determine admissibility of the plaintiffs’ expert, excluded the expert for failing to have a reliable methodology and granted summary judgment in favor of Kumho.  On appeal, the 11th Circuit reversed and held that the lower court erred by applying Daubert to a non-scientific expert.  (119 S. CT. 1167, 1999)

The Supreme Court held that the trial court was correct in applying Daubert to the tire failure analyst because Daubert applied to all experts, as stated in Federal Rule 702: “If scientific, technical, or other specialized knowledge will assist the trier of fact . . . .” (emphasis added) (Fed. R. Evid. 702). Concerning the use of the four Daubert factors, the Supreme Court ruled that a judge “may” consider one or more of the factors or none at all, as long as the judge, in a gatekeeping function, sufficiently evaluates the reliability of the expert testimony. The Court also affirmed its decision in Joiner that the “abuse of discretion” standard is what the court of appeals must apply to the trial judge and allow the trial judge “broad latitude” on whether to rely on the specific Daubert factors.  The Supreme Court, therefore, reversed the 11th Circuit’s decision, finding the 11th Circuit was incorrect in limiting Daubert to only scientists, in ruling out the use of the four factors in determining reliability of the tire expert, and in reversing the trial judge’s decision for applying any or all of the four factors.. (119 S. CT. 1167, 1999)

What Does Kumho Mean for Experts?

Kumho extended Daubert to include all experts and granted trial court judges freedom in the consideration of the four factors when deciding on the admission of expert testimony. The main take away for experts is the need to clearly demonstrate that their methodology, reasoning and conclusions are relevant and reliable, regardless of their field of expertise. Judges will exclude expert testimony if the reliability of the methodology is based on the expert’s qualifications, or mere “ipse dixit” (meaning, “because I say so”). It is still important to demonstrate how the Daubert guidelines are met, regardless of whether the trial court judge ultimately holds an expert to them. 

Submitted by Wendy N. Pearson, President; edited 2015- replaced FRE 702 (2000) w/ 1975 version.


  1. Kumho extended Daubert to include all experts and granted trial court judges freedom in the consideration of the four factors when deciding on the admission of expert testimony. The main take away for experts is the need to clearly demonstrate that their methodology double mattress protector , razai cover price

  2. From tackling piles of assignments to attending class lectures, a part-time job, to a night out with friends, it can get quite frustrating, especially if you don’t manage your time well.