Also known as: reliable method · reliable methodology · reliable methodologies
Written by attorneys · grounded in primary & secondary sources — see below
A standard governing the admissibility of expert testimony that requires the expert's opinion to rest on principles and methods shown to be reliable through testing, peer review, or other indicia of scientific validity. The court performs a gatekeeping function to ensure the methods produce trustworthy results before the opinion reaches the jury. An analytical gap between the data and the proffered conclusion may render the methods unreliable.
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Rina Rahman sued Regal Apparel after a fabric defect allegedly caused severe burns. Her expert reviewed limited lab samples and concluded the manufacturing process caused the flaw. The district court excluded the opinion because the expert's leap from the small sample set to a broad manufacturing defect created an impermissible analytical gap. The appellate court affirmed, holding the exclusion fell within the trial judge's discretion.
Ryan Roberts sued Rocky Mountain Mining after a tire failure on a company truck caused his injuries. The defense offered a self-taught tire analyst who used an untested visual-inspection protocol developed in-house. The court held a Daubert hearing and excluded the testimony because the analyst's methods lacked external validation and produced results too speculative for the facts at issue. The ruling stood on appeal.
The proponent must demonstrate that the expert's principles and methods are reliable and were reliably applied to the facts. Courts consider factors such as testing, peer review, known error rates, and general acceptance, though the inquiry remains flexible. Experience alone does not automatically satisfy the requirement if the underlying methods lack sufficient validation.
No. A witness may qualify through knowledge, skill, experience, training, or education even without degrees or active practice. The focus remains on whether the methods themselves are reliable and properly applied. Concerns about credentials or recency of hands-on work affect weight rather than admissibility.
An impermissible gap exists when the expert's conclusions are not supported by sufficient facts or the methodology used. Courts may exclude testimony if the leap from limited testing or informal data to broad real-world claims lacks adequate foundation. The trial judge's determination on this point receives abuse-of-discretion review on appeal.
The same gatekeeping obligation extends to all expert testimony based on technical or specialized knowledge. Courts retain discretion to consider Daubert factors or other appropriate indicia of reliability tailored to the field. The absence of peer review or published standards does not automatically disqualify the methods if other validation supports reliability.