What are the principles applicable to a motion such as this?

In Schick v. Boehringer, I set out the following general principles applicable to the issues on a motion such as this, at paras. 13-15: First, evidence tendered on a motion for certification of a class proceeding must meet the usual criteria for admissibility… Second, opinion evidence can only be tendered through the evidence of a properly qualified expert … This principle has been applied on certification motions… Third, the plaintiff, who bears the burden of proof, is required to put his/her full case forward in the first instance. The defendant is entitled to know the case that he/she must meet and it is impermissible for the plaintiff to split the case - either by using reply to introduce new evidence that could or should have been made as part of the case in chief or by simply reasserting the merits of his/her case.[References omitted].