The U.S. Government Accountability Office is responsible for, among other things,assisting the Congress in its oversight of the federal government, including agencies’ stewardship of public funds. To use public funds effectively, the government must employ effective management practices and processes, including the measurement of government program performance. Toward these objectives, in March 2009, we published the GAO Cost Estimating and Assessment Guide as a consistent methodology based on best practices that can be used across the federal government to develop, manage, and evaluate capital program cost estimates. The methodology outlined in the Cost Estimating and Assessment Guide is a compilation of best practices that federal cost estimating organizations and industry use to develop and maintain reliable cost estimates throughout the life of an acquisition program.