What is the impact of the exclusion of expert testimony in a medical malpractice case?

different impression of [his] credibility." " ( Dement , supra , 53 Cal.4th at p. 52, 133 Cal.Rptr.3d 496, 264 P.3d 292 ; accord, People v. Smith (2015) 61 Cal.4th 18, 59-60, 186 Cal.Rptr.3d 550, 347 P.3d 530 [explaining that there was no error when the court excluded certain expert testimony after it "issue[d] a narrow ruling" that still permitted testimony "in some areas"].)