Appellate Court Splits On Evidentiary Threshold For Certification

Evidence is required to establish "some basis in fact" for the procedural preconditions to certification. This requires certification judges tread the fine line between screening out inappropriate class proceedings and impermissibly weighing of the merits of the claim based on evidence at the certification stage. The Alberta Court of Appeal's recent decision in Warner v. Smith & Nephew Inc. (Justice Slatter dissenting) illustrates the continuing evolution of the evidentiary threshold required for certification.    

Competing Expert Reports on Causation

The plaintiff in Warner alleged a hip resurfacing system caused toxic levels of metal ions in the blood and applied for certification of a class action against the manufacturer. Each party filed an expert report opining on, among other things, causation of metal ions in the blood. The plaintiff's proposed expert concluded that there was a "great deal of uncertainty as to what the presence of serum metal ions actually