What is the test for an expert opinion in a criminal case?

"California law permits a person with 'special knowledge, skill, experience, training, or education' in a particular field to qualify as an expert witness (Evid. Code, 720) and to give testimony in the form of an opinion (id., 801). Under Evidence Code section 801, expert opinion testimony is admissible only if the subject matter of the testimony is 'sufficiently beyond common experience that the opinion of an expert would assist the trier of fact.' (Id., subd. (a).) The subject matter of the culture and habits of criminal street gangs . . . meets this criterion." (People v. Gardeley (1996) 14 Cal.4th 605, 617; see also id. at p. 619 [expert opinion that described attack would be "gang-

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related activity"].) The prosecution may use hypothetical questions that track the evidence, even if only "thinly disguised," to establish that the crime was gang related. (People v. Vang (2011) 52 Cal.4th 1038, 1045.)

"[A]lthough expert testimony is generally inadmissible on topics 'so common' that jurors of ordinary knowledge and education could reach a conclusion as intelligently as the expert, an expert may testify on a subject about which jurors are not completely ignorant. [Citations.] In determining the admissibility of expert testimony, 'the pertinent question is whether, even if jurors have some knowledge of the subject matter, expert opinion testimony would assist the jury.' [Citations.]" (People v. Lindberg (2008) 45 Cal.4th 1, 45.)

"When expert opinion is offered, much must be left to the trial court's discretion." (People v. Carpenter (1997) 15 Cal.4th 312, 403.) "The trial court has broad discretion in deciding whether to admit or exclude expert testimony [citation], and its decision as to whether expert testimony meets the standard for admissibility is subject to review for abuse of discretion. [Citations.]" (People v. McDowell (2012) 54 Cal.4th 395, 426)

C. Analysis