What is the legal test for judicial review?

The first step in a judicial review application is to determine the appropriate standard of review. There are two standards of review: reasonableness and correctness: Dunsmuir v. New Brunswick, 2008 SCC 9, [2008] 1 S.C.R. 190. The reasonableness standard is a deferential one, while the correctness standard allows the reviewing court to substitute its own decision for that of the tribunal below. Where the nature of the question considered by the decision maker is a question of fact, discretion, mixed law and fact or an interpretation of the tribunal’s “home statute”, the reasonableness standard will most likely apply. A privative clause and the specialized expertise of the decision maker will also indicate that the standard of review is reasonableness. Where the question is a true jurisdictional question, a constitutional question, or a general question of “central importance to the legal system…and outside…the specialized area of expertise” of the decision-maker, a correctness standard will apply: Dunsmuir at 55‑64.