Most mismatches on individual returns are ignored by the Service. It has an automated program that matches data on third-party information returns such as Forms 1099 and 1098 with income and deduction amounts reported on individual income tax returns. Although there are about 25 million mismatches each year, IRS refers for notice only those with significant discrepancies. The agency is tight-lipped as to the level of mismatch that’s considered significant. But it issues just 4 million to 5 million CP2000 notices of such discrepancies annually.