In Miller v Merck Frosst Canada Ltd. the
British Columbia Court of Appeal addressed what it described as its
"two most important, recent, and somewhat contrasting
decisions": Stanway, where the class was certified;
and Charlton, where it was not. At issue in both decisions
was the threshold at the certification stage for evidence of a
methodology to prove causation. The Court in Miller
concluded that Stanway and Charlton are not in
fact at odds with each other. Rather, the type of evidence (whether
expert or not) required to overcome "the common issue
methodology hurdle" must be considered on a case-by-case
The plaintiffs commenced a class action against Merck relating
to the drugs Propecia and Proscar. Propecia is used to treat male
pattern baldness and Proscar is used to treat prostate problems;
both contain finasteride. The plaintiffs alleged that Merck was
negligent in failing to warn consumers of the risk that sexual
dysfunction, which is one of the potential side effects of
finasteride, may persist even after treatment is discontinued. The
action was certified in April 2014, with one of the common issues
being whether either drug could cause sexual dysfunction that
persists after treatment is stopped. On appeal, Merck argued that
the plaintiffs had failed to demonstrate a plausible methodology to
Meaning of "Methodology"
The requirement of a methodology to establish common issues has
received varied treatment in Canadian courts. The Supreme Court of
Canada considered the issue in Pro-Sys Consultants Ltd. v Microsoft
, stating that there must be an actual, not just theoretical,
methodology through which the common issues may be proven. In its
analysis the Court in Miller found that Microsoft
appeared to have a "more onerous methodology" requirement
because it involved "notoriously complex" indirect
purchaser claims, as well as a "massive and diffuse"
The Court then considered the Alberta Court of Appeal decision
in Andriuk v Merrill Lynch Canada Inc.,
(which we previously reported on). In that
case, the Court decided that, depending on the nature of the case,
expert evidence is not necessarily required to establish a
methodology to prove causation on a class wide basis, but that some
evidence of the existence of a methodology was necessary.
Finally, the Court considered the decisions of the British
Columbia Court of Appeal in Stanway v Wyeth Canada Inc. and Charlton v Abbott Industries Ltd. In
Stanway, the court was not persuaded that the plaintiff
had to establish the methodology by which the causation issue would
be determined at the certification stage. However, the evidence in
Stanway included a "gold standard" study proving
the causal connection, while Miller had no such
In Charlton, discussed in a previous post on this blog, the Court
emphasized that while a class action should not be certified if
there is no methodology for addressing the common issue, some
evidence of a methodology to prove causation would be sufficient.
In that case, the plaintiffs had to prove general harm. There was
no consensus among the experts as to the existence of a risk to the
class as a whole, nor was there a consensus as to a methodology to
prove that risk. This differed from Miller, where general
harm was assumed.
In concluding, the Court noted the informational disadvantage of
the plaintiffs at the certification hearing stage. In light of
this, they suggested that evidence of some of the Bradford-Hill
criteria, which are a framework of factors commonly used by
scientists to assess proof of causation, may be enough to satisfy a
court of the validity of an inference of causation.
In Miller the Court found that: an expert opining that
a causal link was "biologically plausible", product
labelling changes made by Merck, and evidence of the Bradford-Hill
criteria was enough to meet the methodology requirement on common
issues. This decision highlights the fact that the requirement for
a methodology to prove the common issues is highly dependent on the
specific facts of each case.
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guide to the subject matter. Specialist advice should be sought
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In Irwin v. Alberta Veterinary Medical Association, 2015 ABCA 396, the Alberta Court of Appeal found that the "ABVMA" failed to afford procedural fairness to a veterinarian undergoing an incapacity assessment.
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