State v. Rimmasch
In State v. Rimmasch, 775 P.2d 388, 392 (Utah 1989) the Court held that "rule 608(a)(1) bars admission of an expert's testimony as to the truthfulness of a witness on a particular occasion." Id.
In that case the Court concluded the expert's testimony, setting forth the reasons why she thought the daughter was telling the truth, "elicited a direct opinion on the daughter's truthfulness at the time she made her allegations of abuse." Id. at 393.
That case precludes a witness from being an oath-helper; in other words, from testifying as to the truthfulness of another witness's testimony.
The Court rejected exclusive use of the general acceptance test set forth in Frye v. United States, 54 U.S. App. D.C. 46, 54 App. D.C. 46, 293 F. 1013 (D.C. Cir. 1923).
Instead, the Court adopted the reasoning of Phillips v. Jackson, 615 P.2d 1228 (Utah 1980), approving inherent reliability rather than general acceptance as "the touchstone of admissibility." Rimmasch, 775 P.2d at 396.
Although "'a showing of general acceptance would generally be sufficient' to show inherent reliability and to justify the admission of scientific evidence," general acceptance was no longer the "sine qua non of admission." Id. at 396-97.
In the absence of general acceptance, other proofs of reliability could also suffice. The Court expressed confidence that "the more flexible test articulated in Phillips seems fully capable of performing the necessary screening function without unduly impeding the flow of reliable scientific evidence to the fact finder." Id. 775 P.2d at 397 n.6.
Rimmasch also set the limits of its own application. Historically, "where expert testimony is based upon novel scientific principles or techniques, courts have long imposed additional tests of admissibility" beyond the standard rules of evidence. Id. at 396.
Thus, "'however the test is formulated . . . a foundation establishing the reliability of new scientific evidence must be established for it to be admissible.'" Id. at 397