The Commonality Test in Class Action Certification: The Battleground of Screening Merits and Fair Process
Bibliographic record
Abstract
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.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.073 | 0.184 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.002 |
| Bibliometrics | 0.004 | 0.002 |
| Science and technology studies | 0.010 | 0.069 |
| Scholarly communication | 0.018 | 0.034 |
| Open science | 0.005 | 0.012 |
| Research integrity | 0.023 | 0.022 |
| Insufficient payload (model declined to judge) | 0.009 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".