[Note: Subsequent to this post the Supreme Court granted review. See, "Review Granted in People v. Archuleta," posted Apr. 11, 2012.]
The introduction of testimonial hearsay as a basis for an expert opinion is permissible, but the trial court should carefully consider whether the evidence should be excluded as more prejudicial than probative, said the Fourth District Court of Appeal in People v. Archuleta (Dec. 29, 2011, E049095), __ Cal.App.4th __ [2011 DJDAR 18637].
A gang expert testified that the defendant was a high-ranking member of a criminal street gang, based in part on statements made to investigators by another alleged gang member after that member had been arrested in an earlier case. The statements were "testimonial" and were inadmissible for the truth of the matters asserted under Crawford v. Washington (2004) 541 U.S. 36. But the statements were not admitted for their truth, but as a basis for the expert's opinion.
The court acknowledged that "it is often difficult if not practically or logically imposible for juries to disregard the truth of hearsay evidence when offered as basis evidence to expert opinion." On the one hand, the jury is instructed that it must decide whether the information on which the expert relied was true and accurate, but on the other hand it is told that it may not consider the information for its truth. But the appellate court concluded that it was bound by Supreme Court precedent establishing the legal distinction between the use of hearsay as substantive evidence and its use by expert witnesses.
In this case, the court was troubled by the fact that the basis evidence was testimonial evidence, which is of suspect reliability. After noting that all hearsay evidence offered as a basis for expert testimony is subject to analysis under Evidence Code §352, it stated that "had defense counsel challenged the admissibility of the statement under ... section 352, the fact it was testimonial and of suspect reliability would have constituted sufficient grounds for substantially redacting it or excluding it altogether." In this case counsel did not object on this ground and, even if he had, the error was harmless.
The court offered "guidelines for trial courts to follow" when there is an objection under §352. First, the court should carefully consider excluding the basis evidence entirely, given that the jury may not appreciate exactly how it is to use the evidence in its deliberations. A limiting instruction may be inadequate and, said the court, "it is especially doubtful that a limiting instruction will cure any prejudice resulting from the admission of a testimonial statement used as basis evidence." Second, the court must balance the expert's need to explain the basis of the opinion, the jury's need for information to evaluate the expert's opinion, the proponent's need to support the opinion, and the risk of prejudicial use of unreliable hearsay.