Bias - Intervention by Decision-Maker. R. v. Chambers
In R. v. Chambers (Ont CA, 2023) the Court of Appeal considered possible 'bias' (though that terms wasn't used) of a criminal trial judge:
 This is not a case involving the sort of actions by a trial judge during the course of a trial that typically attract appellate intervention on the basis of trial fairness. For example, the trial judge did not align himself with the case for the Crown, preclude the appellant from presenting his case, or invite the jury to disbelieve the appellant or his defence: see R. v. Murray, 2017 ONCA 393, 138 O.R. (3d) 500, at paras. 91-97. The trial judge’s actions occurred in the absence of the jury, permitting the expert to base his evidence on the actual baseboard rather than pictures of it. The trial judge’s actions occurred without objection from trial counsel. The circumstances were unusual, but in our view the strong presumption that a trial judge has not improperly intervened during a trial has not been displaced: R. v. Hamilton, 2011 ONCA 399, 271 C.C.C. (3d) 208, at para. 29, leave to appeal refused,  S.C.C.A. No. 547; Murray, at para. 95. We are not satisfied that the trial was rendered unfair by the manner in which the expert evidence was handled.. Nathalie Xian Yi Yan v. College of Traditional Chinese Medicine Practitioners and Acupuncturists of Ontario
In Nathalie Xian Yi Yan v. College of Traditional Chinese Medicine Practitioners and Acupuncturists of Ontario (Div Court, 2022) the Divisional Court considered whether the tribunal member was biased by their active involvement in the evidence phase of the hearing:
 Second, Ms. Yan suggests that the Panel Chair inappropriately took a more active role in the proceedings. Ms. Yan argues, for example, that the Panel Chair allowed independent legal counsel and College’s counsel to take “lots of time” during cross-examination and to “constantly interrupt the Appellant’s legal representative” during cross-examination.
 The Court of Appeal in Chippewas of Mnjikaning First Nation v Chiefs of Ontario, 2010 ONCA 47 at paras 230-231, 233, 24 set out for trial judges the following regarding interventions during a trial:
A determination of whether a trial judge’s interventions give rise to a reasonable apprehension of unfairness is a fact-specific inquiry and must be assessed in relation to the facts and circumstances of a particular trial. The test is an objective one. Thus, the trial record must be assessed in its totality and the interventions complained of must be evaluated cumulatively rather than as isolated occurrences, from the perspective of a reasonable observer throughout the trial … Pursuant to the Statutory Powers Procedure Act, RSO 1990, c S.22, s 25.0.1, Discipline Committees have the power to control their processes during a proceeding. And there is no evidence before this Court to suggest that the Panel Chair acted inappropriately in her role during the proceedings.
An examination of whether a trial judge has unduly intervened in a trial must begin with the recognition that there are many proper reasons why a trial judge may intervene by making comments, giving directions or asking questions during the course of a trial. A trial judge has an inherent authority to control the court’s process and, in exercising that authority, a trial judge will often be required to intervene in the proceedings. …
The reasons a trial judge may properly intervene include the need to focus the evidence on the matters in issue, to clarify evidence, to avoid irrelevant or repetitive evidence, to dispense with proof of obvious or agreed matters and to ensure that the way a witness is answering or not answering questions does not unduly hamper the progress of the trial. ...