An internal auditor gathers a signed contract from the client's legal department, a verbal assurance from the process owner, and a copy of an invoice provided by the vendor being examined. When judging the reliability of this evidence, which principle should the auditor apply first?
- AEvidence obtained from a source independent of the client is generally more reliable than evidence supplied by an interested party. Correct
- BVerbal assurances from a process owner are the most reliable because they come directly from the person accountable for the control.
- CDocumentary evidence is reliable purely because it is written, regardless of who produced or supplied it.
- DThe most recently dated item is the most reliable because it reflects the current state of the process.
Why A is correct: Independence of source is a core determinant of reliability; evidence from a party with no stake in the outcome is less likely to be biased or manipulated.
Why B is wrong: Tempting because the owner is accountable, but oral evidence from an interested internal party is among the least reliable forms and needs corroboration.
Why C is wrong: Form of evidence matters, but written form alone does not confer reliability when the document originates from an interested source such as the vendor.
Why D is wrong: Recency can aid relevance, yet it says nothing about source independence or authenticity, so it is the wrong first test of reliability.