What is the standard of review in judicial review?

The standard of review is reasonableness. As was observed in Dunsmuir v. New Brunswick, [2008] 1 S. C. R. 290, there may be number of different decisions or outcomes that are reasonable, depending on the context and all the circumstances of the case. The court stated "A court conducting a review for reasonableness inquires into the qualities that make a decision reasonable, referring both to the process of articulating the reasons and to outcomes. In judicial review, reasonableness is concerned mostly with the existence of justification, transparency and intelligibility within the decision-making process. But it is also concerned with whether the decision falls within a range of possible, acceptable outcomes which are defensible in respect of the facts and law." (at para. 47) [emphasis added]