The Tax Gap
 

Find resources on this page pertaining to the tax gap — the difference between the amount of tax that taxpayers should pay and the amount that is paid voluntarily and on time. The tax gap can also be thought of as the sum of non-compliance with the tax law. This page provides links to facts sheets that will help you and your clients close the gap.

http://www.irs.gov/newsroom/article/0,,id=158619,00.html