A recent judgment of the Supreme Court of Canada illustrates the continued relevance of the patent unreasonableness standard for judicial review, where prescribed by legislation, even though the standard no longer applies at common law.

The patent unreasonableness standard for judicial review was abolished in the common law by the Supreme Court of Canada in its well-known judgment of Dunsmuir v New Brunswick.[1] The reasons for discarding patent unreasonableness included the difficulty in distinguishing the standard from the reasonableness simpliciter standard in it practical application, and the unpalatability of requiring parties “to accept an irrational decision simply because, on a deferential standard, the irrationality of the decision is not clear enough.”[2]

The Supreme Court’s judgment in Dunsmuir left some uncertainty about whether the patent unreasonableness standard, where provided for in legislation, survived as an independent standard of review. A number of statutes across Canada, enacted prior to the judgment in Dunsmuir, continue to prescribe a standard of patent unreasonableness for the judicial review of tribunal decisions. For instance, in British Columbia, the Administrative Tribunals Act states that the decision of an expert tribunal, in certain cases, could only be overturned if it was patently unreasonable.[3] A number of enabling statutes in Alberta[4] and Ontario[5] also set a standard of review of patent unreasonableness.

The uncertainty led to lower courts having to address the argument that, in light of Dunsmuir, the courts had to apply a reasonableness simpliciter standard to judicial review, even where legislation indicated that a patent unreasonableness standard ought to apply. This argument was rejected by the Alberta Court of Queen’s Bench when considering section 47.1(3) of the Traffic Safety Act in Juneja v Alberta (Registrar of Motor Vehicle Services).[6] While acknowledging the concern highlighted in Dunsmuir about the difficulty in distinguishing between reasonableness simpliciter and patent unreasonableness, the Court was not persuaded that there was no difference between the two standards. The reviewing court was obligated to give effect to the standard of review intended by the legislature for the tribunal whose decision was being reviewed.

Subsequently, Justice Binnie commented in obiter on the continued relevance of the patent unreasonableness standard in the Supreme Court of Canada’s judgment in Canada (Citizenship and Immigration) v Khosa.[7] Taking British Columbia’s Administrative Tribunals Act as an example of a judicial review statute which prescribed a patent unreasonableness standard, Justice Binnie noted that “[d]espite Dunsmuir, patent unreasonableness will live on in British Columbia.” However, Justice Binnie continued to say that, “the content of the expression, and the precise degree of deference it commands … will necessarily continue to be calibrated according to general principles of administrative law.”

Although intended to provide clarity, Justice Binnie’s comments were cited in subsequent cases as indicating that the standard of patent unreasonableness would evolve in accordance with changes to the standard of reasonableness simpliciter, at common law, post-Dunsmuir. This argument was rejected by the BC Court of Appeal in a 2014 judgment.[8] The Court concluded that the standard of patent unreasonableness was a distinct standard, which was free to evolve independently in accordance with principles of judicial interpretation.[9] The present content of patent unreasonableness was defined by reference to the Supreme Court of Canada’s judgment in Ryan v Law Society of New Brunswick.[10] In that case, the Court noted that the distinction between reasonableness simpliciter and patent unreasonableness was rooted in the immediacy or obviousness of the defect.[11] A patently unreasonableness decision was a “clearly irrational” or one which was “so flawed that no amount of curial deference could justify letting it stand.”[12]

In its recent judgment in British Columbia (Workers’ Compensation Appeal Tribunal) v Fraser Health Authority, the Supreme Court declined to judicially review a decision of the Workers Compensation Appeal Tribunal, and concluded that the decision was not patently unreasonable.[13] The Tribunal had found that the breast cancers of 7 lab technicians working in a single hospital were occupational diseases. The Court noted that the applicable standard of review was patent unreasonableness, which required curial deference. While there was no expert medical evidence confirming that the breast cancers were linked to exposure to workplace conditions, it was open to the Tribunal to consider other, circumstantial evidence, in determining whether an illness was an occupational disease.[14]

The judgment in Fraser Health Authority and the prior jurisprudence indicate that the standard of patent unreasonableness applies to the judicial review of tribunal decisions, where specified in legislation. The degree of deference required by this standard of review, and the indicators of a patently unreasonableness decision, have been specified in a number of judgments, including Ryan Estate. The standard is free to evolve in the jurisprudence. However, it is clearly distinct and more deferential than the standard of reasonableness simpliciter.