guidance to same-sex married couples filing income taxes at the state level, where local laws recognizing same-sex marriage can vary considerably. Every year, the Tax Foundation calculates and announces Tax Freedom Days in the United States. These studies have been criticized by the Center on Budget and Policy Priorities (CBPP), a progressive think tank, and in turn the Tax Foundation has responded to or criticized CBPP reports. However, the two groups have worked together on analysis of the marriage penalty in the US federal income tax. Reception In a column for The New York Times blog The Upshot, Josh Barro, a former Tax Foundation employee, criticized the group's approach to scoring the Rubio-Lee tax plan as producing "implausibly rosy results". The Tax Foundation published a response to these criticisms, stating that their model results were "in line with analysis done by other mainstream economists for similar tax changes". In opinion editorials for the New York Times, economist Paul Krugman has characterized the Tax Foundation as "not a reliable source" while criticizing a report by the Tax Foundation comparing corporate tax rates in the United States to those in other countries. Krugman has also accused the Tax Foundation of "deliberate fraud" in connection with a report it issued concerning the American Jobs Act. The Tax Foundation has published various responses to Krugman's criticisms. See also Americans For Fair Taxation Americans for Tax Reform Citizens for Tax Justice Council on State Taxation Institute on Taxation and Economic Policy National Taxpayers Union Tax Policy Center Tax Justice Network References External links Organizational Profile – National Center for Charitable Statistics (Urban Institute) Nonpartisan organizations in the United States Political and economic think tanks in the United States Think tanks based in Washington, D.C. Tax reform in the United States Non-profit organizations based in Washington, D.C. Organizations established in 1937 1937 establishments in the United States 501(c)(3) organizations