Under the Congressional Budget and Impoundment Control Act of 1974, which created CBO, the agency’s primary duty is to provide budget-related information to the Committees on the Budget of the House and Senate. CBO is also required to assist the House and Senate Committees on Appropriations, the House Committee on Ways and Means, the Senate Committee on Finance, other committees, and Members of Congress. The law further requires CBO to prepare several budget projections each year, produce cost estimates of legislation ordered reported by Congressional committees, and publish studies of budgetary issues.
About CBO's Budget and Economic Information
Budget Projections: CBO’s budget projections give the Congress a baseline against which to measure the effects of proposed changes in tax and spending laws. The projections start with the Congress’s most recent budgetary decisions and show what would happen to the federal budget if no policy changes were made over the projection period. 
Specifically, CBO’s baseline projections assume that discretionary spending will increase at the rate of inflation and that entitlement spending and revenues will continue according to current law.
Economic Projections: CBO produces 10-year forecasts of the economy. For the beginning years of that span, a forecast consists of projections of major macroeconomic variables and their fluctuations over the course of the business cycle. For the later years of the span, the forecast relies on long-term trends in the labor force, productivity, and saving. To construct its forecasts, CBO reviews major econometric models and information from commercial forecasting services. It also consults with and relies on the advice of its expert panel of economic advisers.
Monthly Budget Review: Each month, CBO issues an analysis of federal spending and revenue for the previous month and the fiscal year to date. Those Monthly Budget Reviews, which are based on information from the Treasury Department, help to inform the Congress and the public on the monthly status of outlays, receipts, and the deficit or surplus throughout the fiscal year.
Budget Options: CBO produces volumes that discuss a wide range of options for changes in spending and taxes. The options are derived from many sources and, in keeping with CBO’s mandate to provide objective analysis without making recommendations, each option includes arguments for and against it.
Long-Term Budget Outlook: This report presents illustrative scenarios for federal spending and revenues over the next several decades and describes the implications of those scenarios for the economy.
Panel of Economic Advisers
CBO’s panel of economic advisers is composed of leading economists who serve two-year terms. The panel meets twice a year to review and comment on CBO’s preliminary forecasts of the economy and to enhance the quality of CBO’s work.
Current Projections
Budget Projections
Provides a baseline against which to measure the effects of proposed changes in tax and spending laws. Latest projections published in Analysis of the President’s Budgetary Proposals for Fiscal Year 2011.
August 2010excelpdf
Supplemental data on mandatory spending
Economic Projections
CBO's 10-year forecast for the major macroeconomic variables. Latest projections published in the Budget and Economic Outlook: Fiscal Years 2010 to 2020.
August 2010pdf
Long-Term Budget Outlook
JUNE 2010 executive summaryfull report pdf additional info blog post
Major Reports
The Budget and Economic Outlook: An Update
August 2010pdfadditional infoblog post
An Analysis of the President's Budgetary Proposals for Fiscal Year 2011
March 2010htmlpdfblog post
Budget Options, Volume 2
August 2009pdfblog post
Budget Options, Volume 1: Health Care
December 2008pdfchartsblog post
Monthly Reviews and Historical Data
Historical Budget Data
A compilation of data on the government’s revenues, outlays and deficits or surpluses for the past 40 years. Figures are reported in nominal dollars and as a percentage of gross domestic product.
pdfexcel
Status of Discretionary Appropriations
Estimates of discretionary budget authority and outlays for fiscal years 2010 and 2011.
House and Senate status tables
Spreadsheets for Selected Estimates and Projections
A collection of historical CBO data, arranged by category. These spreadsheets are not continuously updated, but rather are a reflection of CBO’s estimates, assumptions, and projections at the time the associated publication was released.
Related Reports
Estimated Impact of the American Recovery and Reinvestment Act on Employment and Economic Output From April 2010 Through June 2010
August 2010pdfblog post
Report on the Troubled Asset Relief Program--March 2010
March 2010pdfblog post
Background Reading
Glossary of Budget and Economic Terms
A general reference defining budgetary and economic terms
CBO’s Role in the Budget Process
A breakdown of the different types of reports and analysis that CBO provides as part of the budget process