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Credibility vs. Reliability

By Brian Sunohara

In Paddy-Cannon et al v. Attorney General of Canada et al, 2019 ONSC 5665, the court went over the differences between credibility and reliability. A credible witness may not be a reliable witness.

Credibility has to do with a witness’s veracity. Reliability has to do with the accuracy of the witness’s testimony. Accuracy engages consideration of the witness’s ability to accurately observe, recall, and recount events in issue.

Any witness whose evidence on an issue is not credible cannot give reliable evidence on the same point. Credibility, on the other hand, is not a proxy for reliability: a credible witness may give unreliable evidence.

Even if a witness appears to be sincere, truthful, and honest, and even if the witness believes what he or she is saying, it does not necessarily follow that his or her evidence is reliable. Credibility alone, in this sense, is not enough.

Moreover, an abundance of detail in the recounting of an event does not necessarily imply an accurate memory.

Justice Corkery noted that memory is fallible. The ability of a witness to give reliable evidence may be affected by the passage of time. Further, life experiences can colour and distort the memory of what occurred.

A trier of fact must pay particular attention to serious inconsistencies in a witness’s evidence, as well as to significant inconsistencies between present testimony and prior accounts. Such inconsistencies may disclose unreliability. There must be a rigorous analysis of whatever independent, extrinsic evidence exists.

In conclusion, a witness who appears to be honest, confident and convincing is not necessarily an accurate witness.