The proper drafting and approval of the internal audit charter by the appropriate parties (e.g., the board or audit committee) offer the clearest evidence that the internal audit activity has achieved organizational independence. The internal audit charter formally defines the purpose, authority, and responsibility of the internal audit activity, including its independence from management and its direct reporting line to the board or audit committee. This document is foundational for establishing and maintaining the independence of the internal audit function.

IIA Standard 1000: Purpose, Authority, and Responsibility

IIA Standard 1110: Organizational Independence