No one knows for certain the precise criteria that the IRS uses to select tax returns for audits, but the collective experience of tax professionals has pinpointed those that are almost certain to raise red flags.

• Income numbers that don’t exactly match your W-2 or 1099s – including income from sales proceeds and debt cancellation.
• Major changes in status or reporting from year to the next – especially in reported charitable contribution or any large itemized deduction, such as for a home office. If you have complete documentation of these items, the auditors will likely leave you alone.
• Math errors – the most common auditing trigger. File electronically and you will reduce your chances of a math error by 80%.