When will a defendant be able to cross-examine an expert's opinion on the basis of hearsay evidence?

Except as provided by law, hearsay evidence is inadmissible. (Evid.Code, 1200, subds. (a), (b).) Nonetheless, hearsay evidence may be admissible under an exception enumerated in the evidence code, other statutes or decisional law. (People v. Otto (2001) 26 Cal.4th 200, 207, 109 Cal.Rptr.2d 327, 26 P.3d 1061.)

Here, well-established decisional law gives parties wide latitude when cross-examining an expert witness to test the credibility of the expert. (People v. Coleman,supra, 38 Cal.3d at p. 90, 211 Cal.Rptr. 102, 695 P.2d 189.) Additionally, expert witnesses may be questioned during cross-examination regarding the basis of their opinion. (Evid.Code, 721, subd. (a).) Thus, the trial court erred by sustaining defendants' hearsay objections. We conclude, however, that any error in excluding the evidence did not result in a miscarriage of justice.