In selecting specific tax returns for audits, the IRS does its own form of data drilling. It has established various categories such as High Income/High Wealth Taxpayers (HIHW), High Income Non Filers (HINF), and Discriminant Index Function (DIF).

As the IRS examination documentation states, DIF is a mathematical technique used to score income tax returns for examination potential……Each return measured under DIF receives a DIF score. Generally the higher the score, the greater the audit potential. DIF score information is treated as confidential, and is not disclosed to taxpayers.

The IRS “dirty dozen” tax scams for 2013, includes identity theft, Phishing (internet fake emails and websites), hiding income offshore, impersonation of Charitable Organizations, and misuse of trusts.