The authority of the internal audit activity is best demonstrated through its ability to determine the scope of internal audit services. This authority, granted by the board and senior management, ensures that internal auditors have the freedom to assess and address risks appropriately across the organization without undue influence, reflecting a key element of internal audit's role in organizational governance.

IIA Standard 1110 - Organizational Independence, which emphasizes the authority of the internal audit activity to define its own scope as a critical aspect of its independence and authority.