Improving Internal Audit's Performance

D.

The correct answer is C. An external quality assessment review would provide the most useful input to IS audit management when developing an action plan for improving internal audit's performance.

An external quality assessment review involves an independent third-party assessment of the internal audit function's effectiveness, efficiency, and compliance with applicable standards and regulations. This type of review provides an objective evaluation of the internal audit function's performance and identifies areas for improvement.

Feedback from departments that have participated in IS audits (option A) would provide valuable information, but it may not be comprehensive or representative of the entire organization. It may also be biased or subjective, depending on the department's experience with the audit.

Industry benchmarking analysis (option B) would provide useful information on how other organizations perform their internal audits, but it may not be directly applicable to the organization being assessed. Internal audit functions vary by industry, size, and complexity, and each organization may have different goals and objectives for its internal audit function.

Results from a training improvement initiative overseen by executive management (option D) would provide some useful information, but it would only address the specific training initiative and may not provide a comprehensive assessment of the internal audit function's overall performance.

In summary, an external quality assessment review is the most comprehensive and objective method of evaluating the internal audit function's performance and identifying areas for improvement. Therefore, it would provide the most useful input to IS audit management when developing an action plan for improving internal audit's performance.