What is the current state of the law on credibility of witnesses?

In Ouellette v. Uddin[1] Shelston J. provided a useful summary for guiding a court’s assessment of witness credibility, (a) assessing credibility is, in every respect, a holistic undertaking incapable of precise formulation; (b) the trial judge need not believe or disbelieve a witness’s testimony in its entirety; (c) the trial judge may believe none, part or all of a witness’s evidence, and may attach different weight to different parts of a witness’s evidence; and (d) the trial judge can assess credibility by considering different factors that include internal and external consistency of witness testimony with the testimony of other witnesses and the documentary evidence, motive, self-interest, clarity and logic of narrative, witness presentation (distinguishing candour from evasive or strategic testimony) and, to a lesser degree, witness demeanour. This list is not exhaustive.