Also known as: expert evidences · expert testimony · expert witness evidence
Written by attorneys · grounded in primary & secondary sources — see below
Testimony or other evidence presented by a witness possessing specialized knowledge, skill, experience, training, or education. The testimony assists the trier of fact to understand the evidence or to determine a fact in issue when the subject matter lies beyond common experience. Courts serve as gatekeepers to ensure the testimony is both relevant and reliable before it reaches the jury.
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Eugene Ellsworth, a forensic accountant, reviewed thousands of transaction records prepared by others and formed an opinion on whether Empire Logistics had overstated revenues. At trial Eugene testified about his conclusions without first establishing that he personally observed any of the underlying transactions. The court admitted the testimony because the personal-knowledge requirement does not apply to expert evidence under Rule 703.
Emily Ellis sued Everlasting Insurance after her policy claim was denied on the ground that a fire was intentionally set. She offered an arson investigator who concluded the fire was accidental based on a novel burn-pattern theory never tested in peer-reviewed studies. The district court excluded the testimony after finding the methodology unreliable under the Daubert factors.
Edith Eberhardt claimed that a defective brake design caused her car accident. Her engineering expert relied on general industry data but never connected the data to the specific brake model at issue. The court excluded the opinion, concluding that the analytical gap between the data and the proffered conclusion was too great.
Elliot Edmonds, an HVAC technician, sued Elite Dynamics for injuries allegedly caused by a faulty ventilation system. He offered an engineer whose opinion rested on specialized technical knowledge rather than hard science. The court applied the Daubert reliability analysis to the engineering testimony and admitted the evidence after finding the methodology sufficiently reliable.
Elise Everly offered a psychologist who used a novel lie-detection technique to support her claim of repressed memory. The court applied the Frye test and excluded the testimony because the technique had not gained general acceptance in the relevant scientific community.
Esther Eisenberg was prosecuted for animal-cruelty videos. The government sought to introduce expert evidence that viewers of such videos were statistically more likely to commit violence. The court excluded the testimony because it rested on an impermissible inference about the defendant's own conduct.
Federal courts apply Federal Rule of Evidence 702 and the Daubert framework. The court acts as gatekeeper to ensure the testimony is both relevant and reliable. Reliability is assessed flexibly by considering factors such as testing, peer review, error rate, standards, and general acceptance.
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No. Rule 602 expressly states that its personal-knowledge requirement does not apply to a witness's expert testimony under Rule 703. An expert may base an opinion on facts or data that the expert has not personally observed, provided those facts or data are of a type reasonably relied upon by experts in the field.
…restriction, not the group for whom the law is irrelevant." Ante , at 894. Looking at this group, the Court inquires, based on expert testimony, empirical studies, and common sense, whether "in a large fraction of the cases in which [the restriction] is relevant, it will operate as a substantial obstacle to a woman's choice to…
…before us. Daubert v. Merrell Dow Pharmaceuticals, Inc. , 951 F.2d 1128, 1131 (9th Cir.1992). The standard for admissibility of expert testimony
…all other factors aside, the price paid to the minority was grossly inadequate, and thus unfair. To this end, plaintiff offered expert testimony in support of his position that $26 was the minimum price that Signal should have been required to pay in return for the right to acquire 100 per cent ownership of UOP. The defendants, on…
…2d, at 1155. "[T]he [trial] court heard extensive testimony
…which only testimony on the issue of guilt is inadmissible. Finally, we agree with the district court’s exclusion of Stevens’s
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Appellate courts review a district court's decision to admit or exclude expert testimony for abuse of discretion. The trial court enjoys wide latitude in performing its gatekeeping function under Daubert and its progeny.
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No. The Daubert framework applies to all expert testimony, including testimony based on technical or other specialized knowledge. Courts may consider the Daubert factors or any other appropriate indicia of reliability when evaluating engineering, technical, or other non-scientific expertise.
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A court may exclude the defendant's expert evidence on mental disease, defect, or other mental condition bearing on guilt or capital punishment if the defendant fails to give the required notice or fails to submit to a court-ordered examination.
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