What is the case law on "pragmatic and functional approach" in medical malpractice cases?

In Dr. Q v. College of Physicians and Surgeons, supra, the Chief Justice discusses the primacy of the pragmatic and functional approach commencing at p. 235. After reviewing the existing law, she states her belief that it will be helpful to re-articulate the focus of the factors involved and update the considerations relevant to each. She emphasizes that “consideration of the four factors should enable the reviewing judge to address the core issues in determining the degree of deference” (para. 26).