The Congressional Budget Office CBO

Until 1974 Congress had no budget numbers of its own and depended on figures from the President's Office of Management and Budget. Richard Nixon's impoundment of billions in appropriated funds brought the dependence to a head, and Congress answered with the Congressional Budget and Impoundment Control Act of July 12, 1974, which created the budget committees, a new budget process, and the Congressional Budget Office. CBO opened on February 24, 1975, under Alice Rivlin, who insisted from the start that it would make projections and estimates but never recommendations.

CBO's best-known product is the cost estimate. Nearly every bill reported by a committee receives one, estimating how it would change spending and revenue over ten years, and those estimates, known as scores, decide whether bills comply with budget rules and often whether they pass. The office also publishes the budget baseline, its projection of spending, revenue, deficits, and debt if current law stays unchanged, along with long-term budget outlooks, analyses of the President's budget, and reports on topics from Social Security solvency to the costs of the nuclear arsenal. Revenue estimates for tax bills come from its partner, the Joint Committee on Taxation.

The Director is appointed jointly by the Speaker of the House and the president pro tempore of the Senate on the recommendation of the budget committees, for a four-year term. CBO has about 275 employees, most of them economists and policy analysts, and by long practice it hires without regard to political affiliation. Directors have been appointed by both parties, and several have served under majorities of the other party.

Because a CBO score can sink a bill, the office is periodically attacked by whichever party dislikes its numbers. Its estimates of how many people would lose coverage under repeal of the Affordable Care Act, its estimate that the 2025 budget law would add more than three trillion dollars to deficits over a decade, and its analyses of tariff revenue all drew sharp criticism from the party in power. Defenders across the spectrum argue that CBO's value lies precisely in giving both parties the same set of numbers, and its record of accuracy compares favorably with private forecasters.