The IRS audits less than 1% of all returns filed each tax year. Some audits result from random selection, while others arise from related examinationsâfor example, a partnership audit triggering audits of the partners. Computer screening also flags statistically unusual returns for audit.IRS auditors review all selected returns. You won't even realize an auditor reviewed the return if they agree with it in full. Otherwise, the auditor forwards the return to an examination group.The IRS conducts three types of audits. Correspondence audits occur entirely through the mail, and often involve sending the IRS documentation for just a few line items on the return. More complex issues might result in an office audit at the local IRS office. For the most complex or serious issues, the IRS will come to your home, business, or accountant during a field audit. The IRS does far more correspondence audits than any other type, especially for small businesses.You will always receive a notice in the mail when the IRS initiates an audit. The IRS will never contact you by phone or email to start an audit, though many phone scammers impersonate IRS employees.Audits end in one of three ways: no change, agreed, or disagreed. No change means the IRS accepts the return as you filed it. In an agreed conclusion, the IRS proposes changes to your return, and you accept them. Disagreed conclusionsâwhere the IRS proposes changes and you do not accept themâcan lead to mediation, an appeal, and eventually disputing the changes in court.