By accepting a role as an engagement supervisor on a highly specialized and technical engagement for which she did not have the expertise, the internal auditor violated the fundamental principle of competency as outlined in The IIA's Code of Ethics. The principle of competency requires internal auditors to perform audit services with the necessary knowledge, skills, and experience. Accepting an assignment without the required expertise undermines the quality and reliability of the audit work.
References:
* The IIA Code of Ethics: "Internal auditors shall engage only in those services for which they have the necessary knowledge, skills, and experience."
* The IIA Standards: Standard 1210 - Proficiency: "Internal auditors must possess the knowledge, skills, and other competencies needed to perform their individual responsibilities."

According to the IIA's guidance on risk management, the internal audit activity is not responsible for managing risks directly but plays a key role in evaluating the effectiveness of risk management processes. One way internal auditors contribute is by using established risk management or control frameworks to assist in identifying and assessing risks during their audits. This enables auditors to provide valuable insights and recommendations regarding risk management practices in the organization.References: The Institute of Internal Auditors (IIA) - Guidance on Risk Management

In situations where the internal audit activity lacks specific financial accounting knowledge for certain audit projects, implementing a guest auditor program is a strategic approach. This program allows the organization to bring in external experts or auditors with specialized knowledge on a temporary basis to address the specific needs of the audit. This approach provides the required expertise without the long-term commitment of a full-time hire, ensuring flexibility and immediate enhancement of the audit team's capabilities.
References:
* The IIA Standards: Standard 1210 - Proficiency: "Internal auditors must possess the knowledge, skills, and other competencies needed to perform their individual responsibilities."
* IIA Practice Guide: "Guest Auditor Programs": Discusses the benefits of bringing in external experts for specialized audit needs.

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.References: 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.

The primary responsibility of the internal audit activity within a risk and control framework is to verify that management has met its responsibility for implementing effective controls. This aligns with the IIA's definition of the internal audit function's role, which is to provide independent and objective assurance that an organization's risk management, governance, and internal control processes are operating effectively.References: The Institute of Internal Auditors (IIA) - International Standards for the Professional Practice of Internal Auditing.