Cause and Effect: The Evidentiary Threshold Required to Certify a Product Liability Class Action

The British Columbia Court of Appeal recently clarified the evidentiary threshold that plaintiffs must satisfy at the certification stage in the context of product liability class actions in Charlton v. Abbott Laboratories, Ltd. This case applies recent jurisprudence addressing the certification requirements, which was addressed in a recent blog post comparing the role of evidence at certification in Canada and the United States.

The Court in Charlton confirmed that plaintiffs alleging that a product causes adverse effects or injury must adduce some evidence of a workable methodology to demonstrate that the product in question was capable of causing adverse effects on a class-wide basis. In so ruling, the Court affirmed that the principles articulated by the Supreme Court of Canada in the three consumer class action certification appeals known as the Indirect Purchaser Trilogy (discussed in an Osler Update entitled “Canada’s Supreme Court Reshapes Consumer Class Actions and Clarifies the Test for Certification Across Canada”) apply in the product liability context. For more details on the Court’s reasons in Charlton, the expert evidence filed in support of the application for certification and the implications of the decision, please refer to our recent Osler Update.


The plaintiffs commenced a class action against Abbott Laboratories, Ltd. and Apotex, Inc. on behalf of all individuals in Canada who were prescribed a drug containing sibutramine, on the basis that ingestion of sibutramine allegedly caused or contributed to adverse cardiovascular health, including heart attacks, strokes, increased blood pressure, increased heart rate, and irregular heartbeat. The product monograph indicated that drugs containing sibutramine should not be prescribed to patients with a history of cardiovascular disease. The expert evidence filed in support of the plaintiffs’ application for certification disclosed some evidence to support a causal relationship between drugs containing sibutramine and cardiovascular disease in individuals with a pre-existing history of cardiovascular disease, but no studies or reports were cited regarding evidence of a causal relationship between drugs containing sibutramine and individuals with no pre-existing history of cardiovascular disease. Notably, some of the members of the class reported suffering from cardiovascular events like heart attacks or strokes after being prescribed sibutramine, while others had not. Furthermore, it was unclear from the evidence how many class members (if any) had a pre-existing history of cardiovascular illness.

The B.C. Supreme Court certified the class. Abbott and Apotex appealed the certification decision on the basis of the failure of the plaintiffs to lead evidence of a methodology for establishing general causation on a class-wide basis.

B.C.C.A.  Overturns Certification Due to an Absence of Proof of Class-Wide Causation

On review of the evidence presented by both sides, the Court found that “while there is no dispute that those with pre-existing cardiopulmonary disease are at a statistically increased risk of adverse cardiac events, this is not a case where the experts disagree on the extent of the risk, but rather, a case where the experts are uncertain whether there is a risk to the class as a whole and cannot describe a methodology for addressing that question.”

The Court concluded that the plaintiff had to failed to demonstrate  evidence of a workable  methodology for demonstrating class-wide causation.

In reaching this conclusion, the Court cited a recent Alberta Court of Appeal decision, Andriuk v. Merrill Lynch, which also applied the evidentiary threshold from the Indirect Purchaser Trilogy in an application to certify a financial services class action. The court in Andriuk held that the failure to adduce evidence of a methodology to establish causation on a class-wide basis was not fatal at the cause of action stage of the certification analysis, but raised “insurmountable obstacles” to certification of the common issues of loss and causation.

All of the common issues initially certified by the trial judge hinged on finding that the plaintiffs had met the evidentiary threshold of “some basis in fact” of class-wide causation. In the absence of such evidence, the common issues could not be certified. The B.C. Court of Appeal overturned the findings of the certification judge, and decertified the class.