One of the key principles for auditing, whether it's internal or external, is that the auditor must approach the work with objectivity and an absence of bias. Structurally, the way that is ensured is to make sure that auditors effectively don't examine activities or practices that they are themselves responsible for. As John mentioned, in the internal audit world in the federal government, essentially, internal auditors or chief audit executives are meant to be serving deputy ministers.
Perhaps the most important structural feature that we put in place was ensuring that chief audit executives reported directly to deputy ministers.