A revenue audit is a two-part process that examines the figures and information on a company tax return against those found in its business records. In general, auditors check the returns of income over a one year period. However, they may review records for prior years too in case they notice any discrepancies. Most companies, big and small, are subject to an audit at some points. Auditors can focus on one or more areas, such as your financial statements, compliance, tax information, or business operations. Basically, their role is to investiagte an existing report, system or entity. During the revenue audit , for exmaple, a company tax return will be compared to its tax records. This can be done through substantive tests, completeness tests, cutoff tests and other procedures.