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A factor considered by courts when assessing the reliability of expert scientific testimony under Federal Rule of Evidence 702. Courts evaluate the known or potential rate at which a methodology produces incorrect results as one indicator of whether the underlying principles and methods are trustworthy.
Sources & Authorities
How it applies
Common Examples
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AI Diagnostic Tool Reliability
In a federal medical malpractice action, patient Maria Ortiz sues Metro General Hospital. The hospital offers Dr. Lin, a neurologist, to testify that Maria's stroke was unavoidable, relying heavily on an emerging AI diagnostic program. Few validation studies exist, and its error rate and standards remain unclear. Maria objects. The judge must scrutinize the program's error rate along with testing, peer review, and acceptance before deciding whether Dr. Lin's testimony rests on a reliable foundation.
Unconventional Subgroup Analysis
In federal court, the partnership Apex Patients sues CardioPharm Inc. over an anti-cholesterol drug. Apex offers Dr. Vega, a biostatistician, who reanalyzed clinical trial data using an unconventional, selectively chosen subgroup method that was not pre-specified, peer reviewed, generally accepted, or tested for error rate. CardioPharm moves to exclude her causation testimony as unreliable. The court grants the motion because the absence of any known error rate signals that the methodology lacks a reliable foundation.
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Cases
Casebooks
Kumho Tire Co. v. Carmichael526 U.S. 137 (1999)
Polygraph Evidence Challenge
A military defendant offers polygraph results to show he did not commit the charged offense. The government objects, citing studies showing significant error rates in criminal investigations. The court excludes the evidence after determining that the documented error rates prevent the technique from meeting the reliability threshold required for admission.
United States v. Scheffer523 U.S. 303 (1998)
Forensic Economist Event Study
Oakbridge Investors sues Apex Capital in federal court for securities fraud. Investors offer Dr. Rivera, a forensic economist, who used a novel event study with alternative market indices and no documented error rate to estimate class-wide damages. Apex moves to exclude her testimony. The judge's primary inquiry focuses on whether the lack of a known error rate renders the methodology unreliable for admission.
Neder v. United States527 U.S. 1, 18-19, 119 S.Ct. 1827, 144 L.Ed.2d 35 (1999)
Common questions
Frequently Asked
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How does a court use error rate when deciding whether to admit expert testimony?+
Courts treat error rate as one nonexclusive factor in the flexible reliability inquiry under Federal Rule of Evidence 702. A high or unknown error rate indicates that the methodology may not rest on a trustworthy foundation, supporting exclusion even if the expert is qualified.
Supporting sources
Does the absence of a documented error rate automatically require exclusion of expert testimony?+
No. The lack of a documented error rate is relevant but not dispositive by itself. Courts weigh it alongside testing, peer review, standards, and general acceptance to decide whether the methodology is sufficiently reliable.
Supporting sources
Can an expert's credentials overcome a high error rate in the underlying method?+
No. Credentials alone do not guarantee admissibility. The court must still examine whether the principles and methods are reliable, and a high error rate in the technique itself can render the testimony inadmissible regardless of the expert's qualifications.
Supporting sources
What role does error rate play when the Daubert factors are applied to non-scientific expert testimony?+
The same flexible reliability analysis applies. Courts may consider error rate even for technical or specialized knowledge, though they retain discretion to use other appropriate indicia of reliability tailored to the field.
Supporting sources
526 U.S. 137 (1999)Evidence
…to the task at hand." Id. , at 597. The Court also discussed certain more specific factors, such as testing, peer review, error rates, and "acceptability" in the relevant scientific community, some or all of which might prove helpful in determining the reliability of a particular scientific "theory or technique." Id. ,…