The IRS does check each and every tax return that is filed. If there are any discrepancies, you will be notified through the mail.

Does the IRS audit every tax return?

The IRS audits less than 1% of all tax returns. However, this doesn't tell the whole story. There are several factors that can make your chances of an audit more or less likely, such as your income and whether or not you claim certain "red flag" deductions.

Do all tax returns get reviewed?

All tax returns are compared with statistical norms, and those with anomalies undergo three layers of review by personnel. Audits then occur either by mail or in meetings at taxpayers' places of business. They can be unpleasant and are sometimes unavoidable.