CBO finds that during the past 40 years, federal spending for 10 of the major means-tested programs and tax credits for low-income households more than tripled as a share of GDP. In 2012, such spending totaled $588 billion, one-sixth of all federal outlays. Over the next decade, spending on those programs will continue to rise under current law, CBO projects, driven mainly by growth in Medicaid and other means-tested health care programs.

The report was written by Will Carrington, Molly Dahl, and Justin Falk, with assistance from other CBO staff.