Glossary

CBO score

The Congressional Budget Office's nonpartisan estimate of how a bill would change federal spending, revenue and deficits.

Also called: CBO estimate, cost estimate, scoring

A CBO score is the official estimate the Congressional Budget Office produces of the budgetary effects of legislation. CBO is a nonpartisan agency of Congress, created by the Congressional Budget Act of 1974, and its director is chosen by congressional leaders rather than the president.

For most bills reported by committees, CBO publishes a cost estimate covering the next ten years, showing changes to spending and revenue year by year. It follows rules set by law and by budget resolutions, which require it to use "static" assumptions about the overall economy, though it accounts for how people change their behavior in response to a policy. Estimates of tax legislation come with the Joint Committee on Taxation. CBO also reports on health coverage effects and publishes long-term budget outlooks.

CBO's score matters because budget rules such as PAYGO and the byrd rule key off it. Members from both parties cite it when it supports their case and criticize it when it does not. Conservatives sometimes argue it underestimates economic growth from tax cuts and prefer dynamic scoring; critics of dynamic approaches say it relies on optimistic assumptions. CBO estimates remain uncertain.

Last reviewed November 8, 2026

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Related terms

Dynamic scoring A budget-estimating method that accounts for how a policy would change overall economic growth, and thus revenues. Budget reconciliation A fast-track budget process that lets the Senate pass certain tax and spending legislation by simple majority, without a filibuster. PAYGO A budget rule requiring that new mandatory spending or tax cuts be offset by spending cuts or tax increases. Budget deficit The amount by which federal spending exceeds revenue in a given year, financed by borrowing. Byrd rule A Senate rule that strips from reconciliation bills any provision that is extraneous to the budget or increases deficits beyond the budget window.