Also known as: Federal Rule of Evidence 703 · FRE 703 · Fed. R. Evid. 703 · Rule 703
Written by attorneys · grounded in primary & secondary sources — see below
A federal rule of evidence that permits an expert witness to base an opinion on facts or data of a type reasonably relied upon by experts in the field even if those facts or data are inadmissible. The expert may not disclose the underlying facts or data to the jury unless the court determines their probative value substantially outweighs their prejudicial effect.
Forrest Falconer, a toxicologist retained by the prosecution, reviewed a blood-alcohol report prepared by an absent analyst. Falconer formed his opinion that the defendant's blood alcohol level exceeded the legal limit after examining the report's raw data and calibration records. At trial the court allowed Falconer to state his conclusion without admitting the report itself because experts in his field routinely rely on such laboratory materials.
Fatima Flores, a forensic geneticist, reviewed a DNA profile report prepared by a nontestifying technician. She compared the profile to a known sample from the defendant and concluded the samples matched. The court permitted her to give that opinion without introducing the underlying report because the data were of a type reasonably relied upon by DNA analysts.
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Felix Franco, a state toxicologist, was asked to testify about a blood sample analyzed by another analyst who did not appear at trial. Franco had no involvement in the testing and offered no independent recalculation of the results. The court excluded his testimony because it would have served merely as a conduit for the absent analyst's findings rather than an independent expert opinion.
Disclosure is permitted only if the court determines that the probative value of the facts or data in helping the jury evaluate the opinion substantially outweighs their prejudicial effect.
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No. The rule expressly allows reliance on facts made known to the expert before or at the hearing provided they are of a type reasonably relied upon by experts in the field.
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Rule 602's personal-knowledge requirement does not apply to expert testimony offered under Rule 703.
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…the hearing,” though such reliance does not constitute admissible evidence of the underlying information. Ill. Rule Evid. 703; Fed. Rule Evid. 703. Both Illinois and Federal Rules bar an expert from disclosing the inadmissible evidence in jury trials but not in bench trials. This is important because Crawford , while departing from…