To enhance the degree of confidence in the financial statements, a qualified external party (an auditor) is engaged to examine the financial statements, including related disclosures produced by management, to give their professional opinion on whether they fairly reflect, in all material respects, the company’s financial performance over a given period(s) (an income statement) and financial position as of a particular date(s) (a balance sheet) in accordance with relevant GAAP. In many cases this is required by law.