What is the test for making a decision in a civil matter?

In answering these questions, our task is not to decide the issue ourselves according to our own yardstick or determine what the correct decision would have been. Our role is rather to approach the reasons provided by the Commissioner with “respectful attention”, with a view to understanding the chain of analysis and ensuring that the decision falls within a range of possible, acceptable outcomes that are defensible in respect of the facts and the law that constrain the Commissioner (Vavilov at paras. 83-86; see also Dunsmuir v. New-Brunswick, 2008 SCC 9, [2008] 1 S.C.R. 190, at para. 47).