If a company has an effective internal audit department,
◦ the internal auditors can express an opinion on the fairness of the financial statements.
◦ their work cannot be used by the external auditors per PCAOB Standard 5.
◦ it can reduce external audit costs by providing direct assistance to the external auditors.
◦ the internal auditors must be CPAs in order for the external auditors to rely on their work.