What impact will a failure to report income have on the credibility of a witness?

The impact a failure to report income has on the credibility of a witness like the plaintiff is a case-specific inquiry. That inquiry must take account of factors that are more encompassing and more subtle than the failure to report income in isolation. A witness who has acted dishonestly in the past is not necessarily a dishonest witness. In some cases, particularly when combined with other factors, the persistent failure of a witness to declare all sources of income on their tax return will result in an adverse finding with respect to the credibility of that witness: see Rhodes v. Biggar, 2010 BCSC 762 at paras. 59-63; Vardabasso v. Sundholm-Millar, [1994] B.C.J. No. 408 at paras. 38-46.