In independent investigations, especially those involving sensitive allegations, the concept of credibility often becomes the cornerstone of decision-making. But what does credibility really mean?

1. What Is Credibility?

Credibility refers to the believability of a person — whether their testimony or account is perceived as honest, sincere, and trustworthy. It’s not about whether the facts are accurate (that’s reliability), but whether the person seems truthful in how they present those facts.

2. How Is Credibility Assessed?

Investigators and decision-makers typically consider:

- Consistency: Are their statements consistent across time and context?

- Plausibility: Does their story make sense given the known facts?

- Motive: Do they have a reason to lie or exaggerate?

- Corroboration: Is their account supported by other evidence?

- Demeanor: Does the person appear calm, evasive, defensive, or confident?

3. What the Courts Say

One of the most influential Canadian cases on credibility is Faryna v Chorny (1952). In this case, Mr. Faryna and Mr. Chorny gave conflicting oral testimony about an alleged agreement to sell land, with no supporting documents or witnesses. The trial judge had to decide whose version of events was more believable. On appeal, the BC Court of Appeal emphasized that credibility should not be assessed solely based on a witness’s demeanor. Instead, the court held that decision-makers must consider whether the testimony aligns with the “preponderance of probabilities which a practical and informed person would readily recognize as reasonable in that place and in those conditions.” This case laid the foundation for a more holistic, context-sensitive approach to credibility — one that prioritizes logic, coherence, and plausibility over mere performance on the stand.

Another helpful case is R. v Morrissey, where the Ontario Court of Appeal distinguished between credibility and reliability.  The court noted that a witness may be entirely honest (credible) but still mistaken (unreliable): “The evidence of a credible, that is, honest witness, may, however, still be unreliable”. This distinction is especially important in investigations where memory, perception, or timing are in dispute.

4. Why It Matters

In cases where physical evidence is limited or absent — such as harassment or misconduct claims — credibility can be the deciding factor. But it’s also subjective and prone to bias, which is why investigators must approach it with care, structure, and transparency.

Understanding credibility as a distinct concept from reliability helps ensure fairer, more defensible findings. It also allows investigators to explain their reasoning clearly, especially when the evidence is contested.