Daubert standard

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:
Important appellate-level opinions that clarify the standard include Judge Alex Kozinski's opinion in Daubert on remand ("Daubert v. Merrell Dow Pharmaceuticals, Inc.", 43 F.3d 1311 (9th Cir. 1995)), and Judge Edward Becker's opinion in "In re Paoli R.R. Yard PCB Litig.", 35 F.3d 717 (3d Cir. 1994).
Definition.
In "Daubert", seven members of the court agreed on the following guidelines for admitting scientific expert testimony:
In 2000, Rule 702 was amended in an attempt to codify and structure elements embodied in the ""Daubert" trilogy." The amended rule then read as follows:
In 2011, Rule 702 was again amended to make the language more clear. The rule now reads:
While some federal courts still rely on pre-2000 opinions in determining the scope of "Daubert", as a technical legal matter, any earlier judicial rulings that conflict with the language of amended Rule 702 are no longer good precedent.
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. Florida passed a bill to adopt the "Daubert" standard as the law governing expert witness testimony, which took effect on July 1, 2013. 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.
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. 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. 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. The appellate court noted that in cases that rely heavily on expert testimony, a district court should set a discovery 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.
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. 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),
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 "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.
According to a 2002 RAND study, post Daubert, the percentage of expert testimony by scientists that was excluded from the courtroom significantly rose. This rise likely contributed to a doubling in successful motions for summary judgment in which 90% were against plaintiffs. Beyond this study, there is little empirical evidence of the impact of "Daubert". However, some critics argue that "Daubert" has disrupted the balance between plaintiffs and defendants, "The exclusion of expert testimony affects plaintiffs far more than defendants because plaintiffs may then not be able to meet their required burden of proof. Furthermore, there is little point in plaintiffs going to the expense of "Daubert" motions to exclude defendant's experts until they know if their case will proceed. So if more experts are now being excluded, then "Daubert" has undoubtedly shifted the balance between plaintiffs and defendants and made it more difficult for plaintiffs to litigate successfully." Similarly, "Daubert" hearings can be subject to various abuses by attorneys attempting to bolster a weak case. These tactics can range from simply attempting to delay the case to driving up the costs of the litigation forcing settlement.
A different pattern has emerged in criminal cases. In criminal cases, the prosecution has the burden of proof and uses a host of forensic science methods as evidence to prove their case; but "Daubert" motions are rarely made by criminal defendants and when they do, they lose a majority of the challenges. Some critics of the use of unreliable science in court argue that "Daubert" has had beneficial effects in civil litigation, but fails to address the underlying pathologies of the forensic science system that leads to dubious verdicts in criminal cases.
Some commentators believe that "Daubert" caused judges to become—in the phrase used in Chief Justice William Rehnquist's dissent in "Daubert"—amateur scientists, many lacking the scientific literacy to effectively fulfill their role as gatekeeper of scientific evidence. Although "science for judges" forums have emerged in the wake of "Daubert" in order to educate judges in a variety of scientific fields, many are still skeptical about the usefulness of the "Daubert" standard in discerning valid science. The responsibility to assess scientific relevance has shifted from highly trained expert witnesses to judges deficient in science education. The "Daubert" ruling furthermore admits the possible introduction of non-peer reviewed data and conclusions. This increasingly shifts the burden of scientific judgement onto judges who have not had an education which would enable them to properly evaluate such data.
Pursuant to Rule 104(a), in "Daubert" the U.S. Supreme Court suggested that the following factors be considered:
The Supreme Court explicitly cautioned that the "Daubert" list should not be regarded by judges as "a definitive checklist or test..." Yet in practice, judges have judged the admissibility of scientific evidence using the ""Daubert" factors" as a checklist; for example, the trial court judge in "Kumho" admitted to erroneously treating the factors as mandatory.
Pronunciation of "Daubert".
Daubert has been pronounced (), () and (). Yale Law School's "Pronouncing Dictionary of the Supreme Court of the United States" gives (audio) and quotes Jason Daubert himself. On the other hand, Daubert's lawyer, Michael H. Gottesman, while noting "the family's name is not dough-bear", reports that "the folks who brought this case to the Supreme Court pronounce their name 'Dow-burt'."
International influence.
The Canadian Supreme Court expressly discussed the "Daubert" standard in R. v. J.-L.J., [2000]. In J.-L.J., the court took a look at the development of U.S. law in this regard, noting the U.S. Supreme Court's rejection of the "Frye" standard and its replacement with the "Daubert" standard. While the court did note that: ""Daubert" must be read in light of the specific text of the Federal Rules of Evidence, which differs from our own procedures," the court also stated in the same sentence that "the U.S. Supreme Court did list a number of factors that could be helpful in evaluating the soundness of novel science." The court then incorporated elements from the "Daubert" standard in their decision regarding the Quebec Court of Appeal ruling while ultimately rejecting the lower court's decision and reinstating the defendant's conviction.
Additionally, in 2005, the United Kingdom House of Commons Science and Technology Select Committee recommended the creation of a Forensic Science Advisory Council to regulate forensic evidence in the UK and observed that: The absence of an agreed protocol for the validation of scientific techniques prior to their being admitted in court is entirely unsatisfactory. Judges are not well-placed to determine scientific validity without input from scientists. We recommend that one of the first tasks of the Forensic Science Advisory Council be to develop a "gate-keeping" test for expert evidence. This should be done in partnership with judges, scientists and other key players in the criminal justice system, and should build on the US "Daubert" test.
The Law Commission for England and Wales proposed a consultation paper (No.190) to adopt a criterion like the "Daubert" standard to help reform the law of evidence in regards to the admissibility of scientific evidence.