Article VII — Opinions and Expert Testimony
Rule 702: Testimony by Expert Witnesses
What is Testimony by Expert Witnesses?
Rule 702 is the gateway for expert testimony. It establishes who qualifies as an expert and what standards their testimony must meet. Following the landmark Daubert decision, the trial judge acts as a gatekeeper to ensure that expert testimony is both relevant and reliable before it reaches the jury.
Source: Fed. R. Evid. 702
Rule Text
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 proponent demonstrates to the court that it is more likely than not that: 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; the testimony is based on sufficient facts or data; the testimony is the product of reliable principles and methods; and the expert's opinion reflects a reliable application of the principles and methods to the facts of the case.
Plain English Explanation
Rule 702 is the gateway for expert testimony. It establishes who qualifies as an expert and what standards their testimony must meet. Following the landmark Daubert decision, the trial judge acts as a gatekeeper to ensure that expert testimony is both relevant and reliable before it reaches the jury.
An expert can be qualified through any combination of knowledge, skill, experience, training, or education — formal academic credentials are not required. A mechanic with decades of hands-on experience may qualify as an expert on engine failure without an engineering degree. Once qualified, the expert must satisfy four reliability requirements: (1) their knowledge must help the jury, (2) the testimony must be based on sufficient facts or data, (3) it must be the product of reliable principles and methods, and (4) the expert must have reliably applied those methods to the facts of the case.
The 2023 amendment clarified the standard of proof by adding 'more likely than not' language, making explicit that the proponent bears the burden of establishing admissibility by a preponderance of the evidence. Courts consider factors like whether the theory can be tested, whether it has been peer reviewed, the known error rate, and whether it is generally accepted in the relevant field — the Daubert factors — though these are not exclusive or mandatory.
Key Points
- 1Experts may be qualified by knowledge, skill, experience, training, or education — formal credentials are not required
- 2The trial judge serves as gatekeeper for expert testimony reliability (Daubert)
- 3Four requirements: helpfulness, sufficient facts/data, reliable methods, reliable application of methods to facts
- 4Daubert factors: testability, peer review, error rate, general acceptance — flexible and non-exhaustive
- 5The proponent must show admissibility by a preponderance of the evidence (2023 amendment)
Common Exam Issues
- Applying the Daubert reliability framework — is the expert's methodology sound?
- Distinguishing between qualifications to testify as an expert and the reliability of the expert's specific opinion
- Whether experience alone qualifies someone as an expert or whether methodology must also be demonstrated
- The difference between Daubert (federal) and Frye (some states) standards for expert testimony
Landmark Cases
- Daubert v. Merrell Dow Pharmaceuticals, Inc.
- General Electric Co. v. Joiner
- Kumho Tire Co. v. Carmichael
Article VII — Opinions and Expert Testimony
This rule is part of Article VII — Opinions and Expert Testimony of the Federal Rules of Evidence.
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