What is the test for giving deference to a decision by an adjudicator in a judicial review?

It is also worth remembering the purpose of judicial review as stated in Dunsmuir itself at para. 28 – to “ensure the legality, the reasonableness and the fairness of the administrative process and its outcomes.” As Voith J. recently observed in Mackenzie v. British Columbia (Superintendent of Motor Vehicles) 2017 BCSC 2392: … Dunsmuir emphasized both the importance of giving deference to administrative decisions and the important role that judicial review serves. A great many subsequent authorities have developed and supported the deference side of this equation. Courts are not meant to parse reasons. Courts should not expect reasons from administrative decision makers that are similar, in structure or content, to what a court would issue. Both the reasons of an adjudicator and the outcomes of a decision should be viewed holistically to support the decision. A reviewing judge should endeavour to supplement the reasons of the decision made before subverting them. At the same time there has to be some meaningful content to the other side of the equation – that being the supervisory role that courts perform on judicial review. That role should not be cosmetic and it should not be a mere rubber stamping of the decision on review. The role is important because it provides ongoing guidance to tribunals and to adjudicators about what is acceptable and what is not. It also ensures that petitioners are afforded a meaningful right of appeal or review. [At paras. 61–2; emphasis added.]