According to the IIA Standards, the chief audit executive (CAE) must ensure that internal audit activities are performed with competence and due professional care. If the internal audit team lacks the necessary knowledge or skills to perform all or part of the work, the CAE must obtain competent advice and assistance. Thus, the CAE's best response to defend the expenditure for an external fraud expert is to refer to the Standards, explaining that the internal audit activity must obtain competent assistance if needed to ensure the investigation is conducted effectively and professionally.

IIA Standard 1210: Proficiency