ISAE 3402 - Assurance Reports on Controls at a Service Organisation 3402.35: ISAE 3402 paragraph 35: Using the Work of the Internal Audit Function

That adequacy is judged on whether the work was done by internal auditors with adequate training and proficiency, was properly supervised, reviewed and documented, rests on adequate evidence for reasonable conclusions, reached conclusions appropriate in the circumstances with reports consistent with the work, and resolved properly the exceptions and unusual matters it disclosed.