The IRS Oversight Board has released its 2011 Annual Report to Congress:

The level of service on IRS toll-free telephones during FY2011 was 70%, a drop of four percentage points over the 74% achieved in FY 2010, and below the 80% level the Board considers acceptable for good taxpayer service.  

IRS enforcement contacts, such as written notices, correspondence examinations, or field examinations, were lower than FY2010. Most of the decline is due to reduced math error notices, which were higher the previous fiscal year because of the First Time Homebuyers Credit. The overall exam coverage rate for individual taxpayers was generally flat, although the rate of examinations for taxpayers with incomes over $1 million continued to grow. Corporate exams increased as well.

The report also addressed two longer-term, strategic issues: the tax gap and the IRS’ information technology (IT) systems. The report said that the IRS made notable progress with its IT program. However, the tax gap – annual uncollected tax revenue – continues to be a serious problem that requires attention. The IRS released an updated estimate of the tax gap in January 2012 based on tax year 2006 returns. The gross and net tax gap rose as a result of the overall growth in the US economy through 2006, but the overall voluntary compliance rates remained approximately the same, at 83%.