Traditionally, an expert was not allowed to offer an opinion on an ultimate issue to be decided by the jury. See, e.g., Washington v. United States, 390 F.2d 444 (D.C. Cir. 1967). Expert testimony regarding ultimate issues, however, is now admissible under Utah Rule of Evidence 704. This rule follows Federal Rule of Evidence 704 verbatim. This rule reads: 'Testimony in the form of an opinion or inference otherwise admissible is not objectionable because it embraces an ultimate issue to be decided by the trier of fact.' Utah R. Evid. 704. See also Gaw v. State, 798 P.2d 1130 (Utah App. 1990) (noting that Utah Rule of Evidence 704 allows an expert to express opinion concerning ultimate issue in the case); 11 J. Moore & H. Bendix, Moore's Federal Practice § 704.10, at VII-64 (1989) ('Under rule 704, testimony of both lay and expert witnesses in the form of an opinion or inference otherwise admissible is not objectionable because it 'embraces an ultimate issue to be decided by the trier of fact.'').
The trial court's exclusion of this testimony, however, can be affirmed on the ground that it was a legal conclusion. Although Rule 704 abolishes ...