What is the test for a plaintiff to be certified as a plaintiff in a medical malpractice case?

The representative plaintiff must come forward with sufficient evidence to support certification, and the opposing party may respond with evidence of its own to challenge certification: Hollick v. Toronto (City), supra at para. 22.

The purpose of a certification motion is to determine how the litigation is to proceed and not to address the merits of the plaintiff's claim; there is to be no preliminary review of the merits of the claim: Hollick v. Toronto (City), supra at paras. 28 and 29. However, the plaintiff must show “some-basis-in-fact” for each of the certification criteria other than the requirement that the pleadings disclose a cause of action: Hollick v. Toronto (City), supra at paras. 16-26.