All decisions rendered by trial courts must be supported by reasons capable of appellate review. This rule creates a minimum standard that requires trial courts to render intelligible decisions.

The Supreme Court of Canada expressed the standard in R. v Sheppard, para. 28:

It is neither necessary nor appropriate to limit circumstances in which an appellate court may consider itself unable to exercise appellate review in a meaningful way. The mandate of the appellate court is to determine the correctness of the trial decision, and a functional test requires that the trial judge’s reasons be sufficient for that purpose. The appeal court itself is in the best position to make that determination. The threshold is clearly reached, as here, where the appeal court considers itself unable to determine whether the decision is vitiated by error. Relevant factors in this case are that (i) there are significant inconsistencies or conflicts in the evidence which are not addressed in the reasons for judgment, (ii) the confused and contradictory evidence relates to a key issue on the appeal, and (iii) the record does not otherwise explain the trial judge’s decision in a satisfactory manner. Other cases, of course, will present different factors. The simple underlying rule is that if, in the opinion of the appeal court, the deficiencies in the reasons prevent meaningful appellate review of the correctness of the decision, then an error of law has been committed.