What is the Daubert Standard?
What are the guidelines to admit expert testimony as evidence?
What is the difference between Daubert standard vs Frye standard?
We will look at what is the Daubert standard and test used by the courts, look at its legal definition, look at the Daubert case and the Daubert trilogy, understand Daubert motions, the hearing, rulings and more.
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Daubert Standard
The Daubert standard (Daubert rule or Daubert principle) is a rule of evidence allowing the courts to evaluate the admissibility of an expert witness’s testimony in court.
Let’s look at Daubert and what it represents.
What is the Daubert standard
The Daubert standard is a test used by the court to determine whether an expert witness presenting a scientific opinion should be admitted as evidence and whether the expert uses scientific reasoning appropriate for the case at bar.
The Daubert standard is a rule of evidence related to the admissibility of the testimony of an expert witness.
Objective of the Daubert standard
The objective of the Daubert Standard is to prevent parties from introducing “pseudoscientific” evidence or “junk science” in the court of law.
The party introducing the expert evidence has the burden of proof to demonstrate that the expert witness’s testimony is considered as “scientific knowledge” and follows a methodology or technique that is generally accepted in the scientific community.
In the context of a lawsuit and the advancement of legal proceedings, if a party wants to introduce the testimony of an expert witness, the court will evaluate whether the expert testimony meets the Daubert criteria to admit or deny its admissibility.
Definition
According to Cornell Law School’s Legal Information Institute, Daubert standard is defined as:
This is the standard used by a trial judge to assess whether an expert witness’s scientific testimony is based on scientifically valid reasoning that which can properly be applied to the facts at issue
What is notable with this definition is that the Daubert standard is a test or evaluation criteria used by the courts to admit or deny the admissibility of an expert witness’s scientific testimony.
Daubert case
In the Daubert case, the Supreme Court reviewed the Frye test and Rule 702 of the Federal Rule of Evidence to establish guidelines overruling the Frye test.
Particularly, the Supreme Court noted how a trial judge must consider an expert witness’ opinion and methodology to determine if we are in the presence of “scientific knowledge”:
- Can the scientific theory be tested or has it been tested?
- Was the technique subjected to peer review and publication?
- What is the known or possible error rate?
- Are there standards controlling its operation?
- Is there a widespread acceptance of the technique within the scientific community?
Role of a trial judge
Based on the guidelines offered by the Supreme Court in Daubert, to admit a scientific expert’s testimony, a trial judge must:
Daubert trilogy
Following the Daubert v. Merrell Dow case, the Supreme Court of the United States further clarified Daubert standards in two other cases.
This has come to be known as the Daubert trilogy.
In 1997, in the case General Electric Co. v. Joiner, 522 U.S. 136, the Supreme Court indicated that an appellate court may use the abuse of discretion standard to review a trial judge’s decision to admit or reject expert testimony.
Furthermore, the Supreme Court stated that admitting an expert testimony is not dependent on how accurate the expert’s opinion may be but rather the expert’s use of supportive data to reach his or her conclusion.
In General Electric Co. v. Joinder, the court’s guidance is the evaluate an expert witness’s conclusion and assess how it correlates with supportive data
Then in 1999, in the case Kumho Tire Co. v. Carmichael, 526 U.S. 137, the Supreme Court indicated that a trial judge may apply the Daubert standard to non-scientific testimonies as well such as engineers and other non-scientific expert witnesses.
In Kumho, the Supreme Court broadened the scope of the Daubert test to apply to other fields that apply scientific approaches and methodologies in their assessment such as economics and psychology.
This was needed to align divergent views among the circuit courts that the Daubert standard should be applied strictly to the scientific field and no other fields.
In Kumho Tire Co. v. Carmichael, the court broadened the Daubert test to have it apply to other fields outside of pure science
Federal Rules of Evidence
As it was stated by the Supreme Court in the Daubert ruling, Rule 702 of the Federal Rules of Evidence superseded the Frye test.
The language of Rule 702 has been amended over the years and no longer represents what the Supreme Court considered when rendering the Daubert decision.
Proper care should be taken to ensure that the interpretation of Daubert does not conflict with the latest wording used in Rule 702.
As of the writing of this article, Rule 702 states:
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.
Frye test
Before the introduction of the Daubert factors, the courts used the doctrine of relevancy along with the Frye test to admit scientific evidence in Federal courts.
The Frye test was established by the U.S. Supreme Court in 1923 when the courts had to determine the admissibility of polygraphic evidence in the court record.
In Frye, the court came to the conclusion that scientific evidence can be admissible if it has gained acceptance within the scientific community.
In essence, the trial judge is the gatekeeper in evaluating what should be admissible as true scientific evidence versus inadmissible pseudoscience evidence.
Daubert test
The Daubert Standard comes from the 1993 U.S. Supreme Court case Daubert v. Merrell Dow Pharmaceuticals Inc., 509 U.S. 579.
The Daubert test can be summarized with the following questions:
- What is the scientific theory used by the expert?
- Has this theory been tested before?
- Was the theory subject to peer review?
- What is the potential or known error rate of this theory?
- Do the peers and scientific community generally accept this theory?
- Has the expert considered alternative conclusions?
- Did the expert extrapolate a conclusion from an unfounded conclusion?
Daubert motions
A Daubert motion is a type of motion in limine filed in court to attack the admissibility of an expert witness’s testimony.
It can be filed at any time during the proceedings including during trial.
A litigation attorney can present an attack by bringing a:
- Pretrial motion
- A motion in limine
- Following an objection raised in discovery after a deposition
- In the context of a summary judgment
- Post-trial motion
A party can present a motion any time during the proceedings seeking a Daubert judgment.
The best practice is to present the Daubert motion as soon as you anticipate the objection.
Waiting too long or presenting a Daubert motion on the day of the trial can be risky.
Such a strategy should be considered with care.
Daubert hearing
A Daubert hearing is when the parties present their legal positions to the court who is required to render a decision on the admissibility or inadmissibility of an expert witness’s testimony or perform a Daubert analysis.
The Daubert hearing is generally held before the hearing on the merits.
It can also be presented at trial.
Although a party may attempt to attack the admissibility of an expert witness’s testimony on the day of the trial, that strategy must be carefully assessed.
Daubert hearings are held out of the jury’s presence where a judge is asked to decide if an expert witness’s testimony should be presented to the jury or not.
Daubert ruling
For the court to rule on a Daubert motion or when a Daubert challenge is presented, it must evaluate the expert witness’s testimony and determine whether it meets the requirements of Rule 702 and the Daubert guidelines.
As such, the court must:
- Evaluate the qualification of the expert
- Consider the qualification of the evidence
- Evaluate the expert’s scientific method
- Assess how the expert obtained the data on the basis of which a conclusion was made
- Assess the scientific approach or methodology used by the expert
Daubert standard vs Frye standard
The Frye standard stems from the case Frye v. United States, 293 F. 1013 (D.C. Cir. 1923) where the courts established a “general acceptance test” to evaluate the admissibility of scientific evidence.
In the Frye, the court considered that if an expert reaches a conclusion based on a well-recognized scientific principle that has gained general acceptance in its field, the courts may consider that evidence is admissible.
In Daubert, the Supreme Court defined a more flexible standard.
The court indicated that a scientific conclusion does not necessarily need to be based on consensus but rather a scientific knowledge and methodology that is sound, can be tested and with acceptable margins of error.
Frye versus Daubert can be viewed as the general acceptance test versus the scientific knowledge.
Daubert standard FAQ

What are the 5 Daubert standards?
In the Daubert case, five standards were outlined to evaluate the appropriateness of a scientific methodology:
- Is the scientific technique tested or can it be tested?
- Has the scientific methodology been subjected to peer review and publication?
- What are the known or potential margins of error and are they acceptable?
- Are there maintenance standards to control its operation?
- Is the scientific methodology generally accepted in the scientific community?
What is the difference between Daubert and Frye standard?
The main difference between the Frye standard vs Daubert ruling has to do with the scope of the admissibility of scientific evidence.
In Frye, the court has one question to answer:
Is the expert’s opinion generally accepted by the scientific community?
In Daubert, the court does not have one question to answer but has guidelines to assess the expert’s opinion as follows:
1- Is the scientific technique tested or can it be tested?
2- Has the scientific methodology been subjected to peer review and publication?
3- What are the known or potential margins of error and are they acceptable?
4- Are there maintenance standards to control its operation?
5- Is the scientific methodology generally accepted in the scientific community?
In Daubert, the court assesses the appropriateness and soundness of the scientific methodology instead of assessing consensus on the topic within the scientific community.
Daubert v Frye comes down to the evaluation criteria to admit or reject expert testimony.
Which states use the Daubert standard?
Not all states in the United States use the Daubert standard.
Approximately half of the states use the Daubert standard while some use the Frye standard such as in California, Illinois, Pennsylvania and Washington.
The Expert Institute has published a list of states and applicable rule of evidence for each state that is quite helpful in understanding the standard for admissibility of scientific evidence.
Daubert is used by the U.S. Federal Courts replacing the Frye standard.
On May 23, 2019, the Supreme Court of Florida adopted the Daubert standard as the test or criteria to use to admit certain expert testimony.
On August 28, 2020, the Maryland Court of Appeals adopted the Daubert standard as well.
What is the Daubert challenge?
The Daubert challenge is the process of excluding an expert’s testimony that is not reliable.
Keep in mind that the decision of a judge to deny an expert testimony is not binding on other courts.
As a result, if one court excludes an expert witness’s testimony, a party may attempt to introduce the same before another court leading to another Daubert challenge.
In cases where an appellate court excludes an expert witness’s testimony, that decision will be binding on the district courts within the appellate court’s jurisdiction.
The Daubert challenge will be limited at that point in time as the appellate court’s decision will be binding to all applicable district courts.