The Congressional Budget Office, along with staff of the Joint Committee on Taxation (JCT), has analyzed the budgetary impacts of the proposal in the President's budget for fiscal year 2012 to increase Internal Revenue Service (IRS) appropriations by $13 billion over the next decade to fund initiatives to enhance tax compliance. The Administration estimated that the proposal would increase revenues by $56 billion over the 2012-2021 period. Using information from the President's budget and additional information provided by the IRS, CBO and JCT estimate that the proposed increase in IRS appropriations would increase revenues above CBO's baseline projection by about $42 billion over the 2012-2021 period. For Congressional scorekeeping purposes, those additional revenues would not be counted as an offset to such spending pursuant to Congressional scorekeeping guidelines. This document provides details about the proposal, the estimated effects on revenues, and the Congressional scorekeeping rules regarding the estimated increases in revenues.