In a 5-2 decision released today, the Supreme Court of Ohio ruled that trial courts must “conduct a rigorous analysis, which may include probing the merits of plaintiffs’ claims, to ensure that the prerequisites of Civ.R. 23 are satisfied.” The Supreme Court of Ohio reversed the Sixth District Court of Appeals decision in Stammco v. United Telephone Company of Ohio and reinstated the trial court’s order that rejected plaintiffs’ amended class definition, holding that “[e]ven though the trial court’s consideration of the merits here was improper, its order denying certification of the class was correct because plaintiffs’ proposed amended class does not satisfy the prerequisites of Civ.R. 23.” 

You can find the full decision here