The court decided that Dunsmuir received procedural fairness because of the hearing before the adjudicator and maintained the eight-month decision.

The Court of Appeal decided that reasonableness was the correct standard and that the adjudicator was unreasonable because the employer dismissed the employee at pleasure, and the common law rules did not require any more procedural fairness than Dunsmuir had received.

The Court began by canvassing the recent history of administrative law decisions on the standard of review, including Canadian Union of Public Employees, Local 963 v New Brunswick Liquor Corp, Crevier v Quebec (AG), Canada (Director of Investigation and Research) v Southam Inc and Pushpanathan v Canada (Minister of Citizenship and Immigration).

The Court noted the general unworkability of the current state of the judicial review of administrative decisions in Canada.

In response, the Court decided to dispense with having three standards of review: correctness, reasonableness (simpliciter), and patent unreasonableness.

Firstly, courts must ascertain whether the jurisprudence has already determined in a satisfactory manner the degree of deference to be accorded with regard to a particular category of question.

When applying the correctness standard, a reviewing court will not show deference to the decision maker’s reasoning process; it will rather undertake its own analysis of the question.

[9] The presumption of reasonableness in administrative review suggested by Binnie J in Dunsmuir did not find majority support at the time but has since been accepted by the Supreme Court in other cases.

[10] That presumption of reasonableness has since led to a more deferent view being taken by courts in Canada in reviewing administrative decisions.