Which statement about the failure of an auditor to detect material misstatements is always true?

• A. The auditor's failure is evidence of inadequate planning: performance or judgment.
• B. The auditor did not comply with Philippine Standards on Auditing.
• C. The auditor has the burden of defending the quality of his audit.
• D. Such a failure is an indication of absence of the auditor's professional competence and due care.

Answer: (C)

Defending the quality of the audit is a fundamental expectation because audits are performed under established standards, and the auditor must justify that the work meets those standards. Even when material misstatements are not detected, this does not automatically prove inadequate planning or performance, noncompliance with standards, or lack of competence or due care. Audits face inherent limits, such as sampling risk and estimation uncertainty, which can allow misstatements to go undetected despite proper procedures. Therefore, the statement that the auditor bears the burden of defending the quality of the audit is the most consistently true principle.