In United States federal law, the Daubert standard ( ) is a rule of evidence regarding the admissibility of expert witness testimony. A party may raise a Daubert motion, a special motion in limine raised before or during trial, to exclude the presentation of unqualified evidence to the jury. The Daubert trilogy are the three United States Supreme Court cases that articulated the Daubert standard:
Daubert v. Merrell Dow Pharmaceuticals, Inc. (1993), which held that Rule 702 of the Federal Rules of Evidence did not incorporate the Frye standard as a basis for assessing the admissibility of scientific expert testimony, but that the rule incorporated a flexible reliability standard instead; General Electric Co. v. Joiner (1997),522 U.S. 136 (1997) which held that a district court judge may exclude expert testimony when there are gaps between the evidence relied on by an expert and that person's conclusion, and that an abuse-of-discretion standard of review is the proper standard for appellate courts to use in reviewing a trial court's decision of whether it should admit expert testimony; Kumho Tire Co. v. Carmichael (1999),526 U.S. 137 (1999) which held that the judge's gatekeeping function identified in Daubert applies to all expert testimony, including that which is non-scientific.
Important appellate-level opinions that clarify the standard include Judge Alex Kozinski's opinion in Daubert on remand, and Judge Edward Becker's opinion.
Definition In Daubert, seven members of the court agreed on the following guidelines for admitting scientific expert testimony: Judge is gatekeeper: Under Rule 702 of the Federal Rules of Evidence, the task of "gatekeeping", or assuring that scientific expert testimony truly proceeds from "scientific knowledge", rests on the trial judge. Relevance and reliability: This requires the trial judge to ensure that the expert's testimony is "relevant to the task at hand" and that it rests "on a reliable foundation". Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579, 584-587. Concerns about expert testimony cannot be simply referred to the jury as a question of weight. Furthermore, the admissibility of expert testimony is governed by Rule 104(a), not Rule 104(b); thus, the judge must find it more likely than not that the expert's methods are reliable and reliably applied to the facts at hand. Scientific knowledge = scientific method/methodology: A conclusion will qualify as scientific knowledge if the proponent can demonstrate that it is the product of sound "scientific methodology" derived from the scientific method.Daubert v. Merrell Dow Pharmaceuticals, Inc. (1993) 509 U.S. 579, 589. Illustrative factors: The court defined "scientific methodology" as the process of formulating hypotheses and then conducting experiments to prove or falsify the hypothesis, and provided a set of illustrative factors (i.e., not a "test") in determining whether these criteria are met: Whether the theory or technique employed by the expert is generally accepted in the scientific community; Whether it has been subjected to peer review and publication; Whether it can be and has been tested; Whether it has a known error rate; and Whether the research was conducted independent of the particular litigation or dependent on an intention to provide the proposed testimony.Daubert v. Merrell Dow Pharmaceuticals, Inc. 43 F.3d 1311 (9th Cir. 1995)
In 2000, the Federal Rules of Evidence, Rule 702 was amended in an attempt to codify and structure elements embodied in the "Daubert trilogy".
Use Although the Daubert standard is now the law in federal court and over half of the states, the Frye standard remains the law in some jurisdictions including California, Illinois, Pennsylvania, and Washington.Giannelli & E. Imwinkelried, Scientific Evidence §§ 1.06, 1.16 (4th ed. 2007). Florida passed a bill to adopt the Daubert standard as the law governing expert witness testimony, which took effect on July 1, 2013.Reuters On May 23, 2019, the Florida Supreme Court accepted the Daubert standard. On August 28, 2020, The Maryland Court of Appeals adopted the Daubert standard.Rochkind v. Stevenson, 471 Md. 1 (2020), https://www.mdcourts.gov/data/opinions/coa/2020/47a19.pdf
Although trial judges have always had the authority to exclude inappropriate testimony, prior to Daubert, trial courts often preferred to let juries hear evidence proffered by both sides. Once certain evidence has been excluded by a Daubert motion because it fails to meet the relevancy and reliability standard, it will likely be challenged when introduced again in another trial. Even though a Daubert motion is not binding to other courts of law, if something was found untrustworthy by one court, other judges may choose to follow that precedent. Of course, a decision by an appellate court that a piece of evidence is inadmissible under Daubert would be binding on district courts within that court's jurisdiction. An evidentiary hearing on the motion may not be necessary if the court finds that it would not assist the court in ruling on any of the matters in the motion.
Timing To attack expert testimony as inadmissible, counsel may bring pretrial motions, including motions in limine. The motion in limine may be brought prior to trial, although counsel may bring the motion during trial as well.See, e.g., Smoot v. Mazda Motors of America, Inc., 469 F.3d 675, 676 (7th Cir. 2006) (case dismissed after plaintiff expert's testimony excluded); Curtis v. M&S Petroleum, Inc., 174 F.3d 661, 667 (5th Cir. 1999); United States v. Nichols, 169 F.3d 1255, 1265-1266 (10th Cir. 1999 ); Heller v. Shaw Indus., Inc., 167 F.3d 146, 155, 157-158 (3d Cir. 1999); Ruiz-Troche v. Pepsi Cola of Puerto Rico, 161 F.3d 77, 90 (1st Cir. 1998); Jack v. Glaxo Wellcome Inc., 239 F. Supp. 2d 1308, 1319 (D. Ga. 2002) (rejecting objection of untimeliness of motion in limine to exclude expert testimony on ground that motion in limine is not dispositive); United States v. Lester, 234 F. Supp. 2d 595, 597-598 (E.D. Va. 2002) (criminal defendant's motion to allow expert testimony regarding reliability of eyewitness testimony denied); Lentz v. Mason, 32 F. Supp. 2d 733, 737 (D.N.J. 1999). A motion attacking expert testimony should be brought within a reasonable time after the close of discovery if the grounds for the objection can be reasonably anticipated.See, e.g., Pineda v. Ford Motor Co., 520 F.3d 237, 241-242 (3d Cir. 2008) (after deposition of plaintiff's expert, defendant filed alternative motions to exclude testimony of plaintiff's expert and for summary judgment, and motion for Daubert hearing). The hearing should be made well in advance of the first time a case appears on a trial calendar.
In one case where a Daubert hearing was conducted on the day of the trial, in which the district court excluded all plaintiff's expert testimony, resulting in the dismissal of all claims, the appellate court remanded the case because of multiple irregularities and a defective record of lower court proceedings.Webster v. Fulton County, Ga., 85 F. Supp. 2d 1375, 1377 (N.D. Ga. 2000) (denying defendant's Daubert motion as untimely, when brought after court had relied on plaintiff expert's report in denying defense summary judgment motion, and within days of trial date). See also Alfred v. Caterpillar, Inc., 262 F.3d 1083, 1087 (10th Cir. 2001 ) (counsel should not sandbag Daubert concerns until close of opponent's case; however, appellate court did not reach issue of late filing of motion because district court chose to address defendant's Daubert objections on merits, rather than deeming them waived); Pullman v. Land O'Lakes, Inc., 262 F.3d 759, 763 (8th Cir. 2001) (appellate court noted with disapproval that defendant failed to bring Daubert motion until shortly before the trial began; Daubert inapplicable to experimental test evidence not presented by expert witnesses). The appellate court noted that in cases that rely heavily on expert testimony, a district court should set a discoverySee Smith v. Ford Motor Co., 215 F.3d 713, 722 (7th Cir. 2000) . See also Goebel v. Denver and Rio Grande W. R.R., 215 F.3d 1083, 1087 (10th Cir. 2000) (district court orally denied motion to exclude expert testimony on morning of trial); McPike v. Corghi S.p.A., 87 F. Supp. 2d 890, 891 n.1 (E.D. Ark. 1999) (court telephoned attorneys with ruling denying defendant's motion to exclude plaintiff's expert testimony, because closeness of trial did not allow time for formal written memo and order at that time; court later rendered substituted memorandum and order, fully stating reasons for its decision in writing). and trial schedule that realistically provides both sides with an adequate opportunity to introduce necessary evidence. The application of Federal Rule of Evidence 702 to proposed expert testimony can often be an uncertain process and is best conducted in such a manner that litigants have a reasonable opportunity to locate experts who meet the rule's requirements.
In another case in which the defendant was apparently at fault for filing a motion to exclude expert testimony one week before the trial date, the district court denied the motion on that ground, but it advised the defendant that it might conduct its own voir dire of the expert in question before he testified. The district court preliminarily found that defendant's motion was predicated on a ruling made almost three months earlier by a district court in another state, and that defendant had shown no good cause for waiting to file the motion. The defendant ultimately lost that case, following the admission of the disputed expert testimony, and ultimately failed in its appeal.See Clay v. Ford Motor Co., 215 F.3d 663, 674 (6th Cir. 2000)
History Prior to Daubert, relevancy in combination with the Frye standard were the dominant standards for determining the admissibility of scientific evidence in Federal courts. Frye is based on a 1923 Federal Court of appeals ruling involving the admissibility of polygraph evidence.Frye v. United States, 293 F. 1013 (DC Cir. 1923) Under Frye, the court based the admissibility of testimony regarding novel scientific evidence on whether it has "gained general acceptance in the particular field in which it belongs". The trial court's gatekeeper role in this respect is typically described as conservative, thus helping to keep pseudoscience out of the courtroom by deferring to those in the field.
In Daubert, the Supreme Court ruled that the 1923 Frye standard was superseded by the 1975 Federal Rules of Evidence, specifically Rule 702 governing expert testimony. Rule 702 originally stated (in its entirety),
In Daubert, the court ruled that nothing in the Federal Rules of Evidence governing expert evidence "gives any indication that 'general acceptance' is a necessary precondition to the admissibility of scientific evidence. Moreover, such a rigid standard would be at odds with the Rules' liberal thrust and their general approach of relaxing the traditional barriers to 'opinion' testimony." By requiring experts to provide relevant opinions grounded in reliable methodology, proponents of Daubert were satisfied that these standards would result in a fair and rational resolution of the scientific and technological issues which lie at the heart of product liability adjudication. Daubert has not appeared to further the Federal Rules philosophy of admitting generally all relevant testimony, and specifically of relaxing the traditional barriers to 'opinion' testimony. The Daubert decision has instead been heralded by some political commentators as one of the most important Supreme Court decisions in imposing higher barriers for toxic tort and product liability cases, by allegedly reducing the volume of so-called junk science in the court room.