“Reasons serve three main functions: they communicate to the affected parties why the decision was made, they provide accountability, and they permit effective appellate review. They also focus the decision-maker, to help ensure fair and accurate decision-making. See R. v. R.E.M., 2008 SCC 51 ¶ 11, 12; see also R. v. Sheppard, 2002 SCC 26 ¶ 15, 24.
At ¶35, 43, 44 of R. v. R.E.M., the Supreme Court summarized three principles that guide appellate courts when considering what is required of a trier in terms of reasons. First, appellate courts should take a functional, substantive approach to the sufficiency of reasons. They are to read the reasons as a whole, in the context of the evidence and arguments at trial, and with an appreciation for the purposes or functions for which they are delivered.
Second, the basis for the decision must be “intelligible”, meaning capable of being made out, and logically connected to its basis. The trier need not set out his or her process in arriving at the decision in detail, nor must he or she necessarily provide detailed recitations of the evidence or the law. Rather, the reasons must show, when read in context of the record and the submissions, that the trier has “seized the substance of the matter”. The degree of detail in any particular case may vary with the circumstances.
Third, to determine whether the logical connection exists, the appellate court should look to the evidence, the submissions and the history of the trial to determine the “live issues” as they emerged during the trial.
An appellate court must start from a stance of deference towards the trier’s perception of the facts. It must ask itself whether the reasons in context explains the basis for the decision. If the evidence is contradictory, it should ask itself whether the trier recognized and dealt with the contradictions. It should do so similarly with difficult or novel questions of law. The critical question to ask is whether the reasons, considered in the context of the evidentiary record, the live issues as they emerged at trial and the submissions of counsel, deprive the appellant of the right to meaningful appellate review? If the appellate court concludes that the trier, on the record as a whole, did not deal with the substance of a critical issue, then it may conclude that the deficiency constitutes an error in law. See R. v. R.E.M. ¶ 52-57.
See also Canada (Minister of Citizenship and Immigration) v. Vavilov, 2019 SCC 65 ¶ 79-91.”