Does a failure to mitigate constitute contributory negligence or novus actus interveniens?

However, mitigation is not a causation question and a failure to mitigate is neither contributory negligence nor a novus actus interveniens: see Janiak v. Ippolito, supra, at 167-68. Further, as Wilson J. explained, speaking for the court, contributory negligence deals with pre-accident events and mitigation with post-accident events. Moreover, although the doctrines of mitigation and novus actus interveniens may coincide where the alleged failure to mitigate consists of a discrete event, such as the plaintiff’s refusal to undergo remedial surgery that was in issue in that case, a failure to mitigate does not break the chain of causation and the defendant remains liable for unavoidable losses subsequently incurred by the plaintiff, but not for losses that were reasonably avoidable.