What is the standard of review for a decision of an administrative tribunal?

Dr. Q, [Dr. Q v. College of Physicians and Surgeons of British Columbia, 2003 SCC 19] confirmed that when determining the standard of review for the decision of an administrative tribunal, the intention of the legislature governs (subject to the constitutional role of the courts remaining paramount—i.e., upholding the rule of law). Where little or no deference is directed by the legislature, the tribunal’s decision must be correct. Where considerable deference is directed, the test of patent unreasonableness applies. No single factor is determinative of that test. A decision of a specialized tribunal empowered by a policy-laden statute, where the nature of the question falls squarely within its relative expertise and where that decision is protected by a full privative clause, demonstrates circumstances calling for the patent unreasonableness standard. By its nature, the application of patent unreasonableness will be rare. A definition of patently unreasonable is difficult, but it may be said that the result must almost border on the absurd. Between correctness and patent unreasonableness, where the legislature intends some deference to be given to the tribunal’s decision, the appropriate standard will be reasonableness. In every case, the ultimate determination of the applicable standard of review requires a weighing of all pertinent factors…