What is the current state of the law on the authority of expert testimony in medical malpractice?

In Mazur v. Lucas, 2010 BCCA 473 at para. 40, the court summarized the leading authorities and concluded that an expert witness may properly rely on a variety of source including, but not limited to, “his own intellectual resources, observations or tests, as well as his review of other experts' observations and opinions, research and treatises, information from others” and hearsay, and that the correct response is not to withdraw this evidence but, rather, to address the issue of weight in an appropriate self-instruction or instruction to the jury. On the issue of determining weight, the court commented at para. 40: The weight the trier of fact ultimately places on the opinion of the expert may depend on the degree to which the underlying assumptions have been proven by other admissible evidence. The weight of the expert opinion may also depend on the reliability of the hearsay, where that hearsay is not proven by other admissible evidence. Where the hearsay evidence (such as the opinion of other physicians) is an accepted means of decision making within that expert's expertise, the hearsay may have greater reliability.