What is the test for abuse of expert testimony in a criminal case?

her testimony quoting, paraphrasing or summarizing the calls, he has made no showing that a different result is reasonably probable had the tapes themselves been played for the jury. (People v. Watson (1956) 46 Cal.2d 818, 836-837.)

2. Detective Jara's testimony as an expert witness

Defendant next asserts that the trial court erred in allowing Detective Jara to offer her opinion on the meaning of jailhouse calls and on the conduct of gang members generally because she was not an expert witness and because her testimony was in any event "unnecessary" because "the jury could have drawn its own inferences and conclusions" about the calls. We review challenges to expert testimony for an abuse of discretion. (People v. Montes (2014) 58 Cal.4th 809, 861.)