What is the test for admitting expert testimony in a medical malpractice case?

" 'Expert opinion testimony is admissible only if it is "[r]elated to a subject that is sufficiently beyond common experience that the opinion of an expert would assist the trier of fact." ' [Citation.] 'When expert opinion is offered, much must be left to the trial court's discretion.' [Citation.] 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. [Citation.]" (People v. McDowell (2012) 54 Cal.4th 395, 425-426.)

b. Admissibility of CSAAS Evidence