R. v. Milliken, 2015 ONCA 897:
 A misapprehension of the evidence will constitute a miscarriage of justice if the trial judge was mistaken as to the substance of material parts of the evidence, and those errors played an essential part in the reasoning process: R. v. Morrissey(1995), 97 C.C.C. (3d) 193 (Ont. C.A.), at p. 221. The misapprehension must go to the substance rather than to the detail and must be material rather than peripheral to the reasoning of the trial judge: R. v. Lohrer, 2004 SCC 80,  3 S.C.R. 732, at para. 2. The errors must play an essential part in the reasoning process resulting in a conviction.
Of the Law Societies of Upper Canada and Nunavut