Tax evasion in the United States unlawful gains as income when filing annual tax returns (see e.g., "James v. United States") although such income is typically not reported. Suspected lawbreakers, most famously Al Capone, have been successfully prosecuted for tax evasion when there was insufficient evidence to try them for their non-tax related crimes. Reporting illegal income as earned legitimately may be illegal money laundering. In the United States, the IRS estimate of the 2001 tax gap was $345 billion. For 2006, the tax gap is estimated to be $450 billion. A more recent study estimates the 2008 tax gap in the range of $450 to
Tax evasion in the United States based on total positive income. Using line items from the auditor's checksheet, discriminant analysis, and a scoring mechanism, each return was awarded a score, known as a "Z-score". Higher Z-scores were associated by IRS personnel with a higher risk of tax evasion. However, the Discriminant Index Function (DIF) system did not provide examiners with specific problematic variables or reasons for the high score and so each filing had to be manually examined by an auditor. The IRS may carry out investigations to determine the correctness of any tax return and collect necessary income tax, including requiring the taxpayer to provide