The Commonality Test in Class Action Certification: The Battleground of Screening Merits and Fair Process

The class action certification test requires “claims that … raise common issues.” The common law jurisdictions in Canada have become divided as to the evidentiary basis in fact required to establish that requirement. Some have recently held that the plaintiff must adduce some basis in fact that: (a) the proposed issues are common to the class; and (b) the proposed issues exist. Others have required evidence of commonality only, having identified incongruencies in principle in requiring evidence of the existence of issues proposed to be common to the class. This article takes a closer look at what it means to superimpose an evidentiary burden of existence on the commonality inquiry. The article reviews a sample of certified common issues, concluding that the existence inquiry is at its core a screening of the substance and merits of the common elements of the claim. In some cases, that merits screening is procedurally harmless. However, that screening often becomes incompatible with other certification caselaw that has adopted a rigid exclusionary approach to pre-certification discovery and an exacting test of evidence admissibility. The end result, when these lines of authority operate together, is a compromise in fair process: a process that demands evidence, and only evidence that would be admissible at trial, that it denies discovery of, even in cases where the evidence is solely in the possession and control of the defendant. This article calls for a holistic, rather than a piecemeal, approach to these elements of certification so that merits screenings — if they are desirable and permitted — are conducted openly and with fair and proportionate procedural safeguards.