Does a trier of fact have to consider standard of care before determining whether there has been a breach of the standard or otherwise?

I agree with my colleague, at paras. 59 to 63, that typically, it makes sense for the trier of fact to consider causation only after finding a breach of the standard of care: see, for example, Bafaro v. Dowd, 2010 ONCA 188, 260 O.A.C. 70, at paras. 35-36. Determining standard of care before causation ensures that the trial judge does not wrongly reason backwards from the fact of the injury to determine that the standard of care has been breached. However, I also agree with my colleague’s observation that at times the court will need to determine “what happened” (that is, the factual cause of the plaintiff’s injury) in order to resolve whether the standard of care has been breached. Determining factual (and not “but-for”) causation is sometimes necessary before a conclusion can be reached on whether there has been a breach of the standard of care.