Triers of fact to be given leeway in credibility and findings of fact

R. v Govenlock, 2015 ABCA 343:

[3]               Trial judges have considerable leeway in their appreciation of the evidence and the proper inferences to be drawn therefrom, in their assessment of the credibility of witnesses, and in their ultimate assessment of whether the Crown’s case is made out beyond a reasonable doubt: R. v Biniaris, 2000 SCC 15 (CanLII) at paras. 24, 37, [2000] 1 SCR 381. Findings of credibility and of fact by a trial judge are entitled to great deference, and should only be interfered with on appeal if they are unreasonable, or in other words if they display palpable and overriding error: F.H. v McDougall, 2008 SCC 53 (CanLII) at paras. 55, 72, [2008] 3 SCR 41; R. v W.(R.), 1992 CanLII 56 (SCC), [1992] 2 SCR 122 at pp. 131-2, 137 NR 214; Housen v Nikolaisen, 2002 SCC 33 (CanLII) at paras. 10-18, [2002] 2 SCR 235; R. v Cornell, 2009 ABCA 147 (CanLII) at para. 2, 454 AR 362, 6 Alta LR (5th) 203. To decide that a verdict is unreasonable, an appellate court must determine that the verdict is one that a properly instructed jury or a judge could not reasonably have rendered: Biniaris at para. 36.