It has been widely reported that a 10-page Tax Policy Center (TPC) study released July 2011 is where Romney got his 47% figure from.
Says The Hill:
The most recent study by the Center, in 2011, found that 46 percent of taxpayers would not be eligible to pay the federal individual income tax either because of their low income or owing to specific tax breaks.
But in 2009, it estimated that threshold was set at 47 percent.Due to much misunderstanding of the report, the TPC issued a blog post on July 27, 2011 to clarify a few points.
TPC is a partnership of the liberal Urban Institute and Brookings Institution.
The authors of that study are Rachel Johnson, James Nunns, Jeffrey Rohaly, Eric Toder, and Roberton Williams.
Here is what the Center on Budget and Policy Priorities (CBBP) has to say about the TPC study.
Here is what Media Matters has to say about how Republicans have portrayed TPC. Also, here is a previous Think Tank Watch post on TPCs analysis of Romney's tax plan and push-back from American Enterprise Institute (AEI) and others.
Here is a piece that William Gale and Donald Marron wrote for the Washington Post titled "5 Myths about the 47 Percent."
Funders of TPC include: AARP, American Bar Association, Amgen, Ford Foundation, The Bill and Melinda Gates Foundation, New York University School of Law, and The Rockefeller Foundation. A more complete list of TPC funders can be found here.
Donald Marron, a former George W. Bush economic official, is the Director of TPC. That said, TPC has plenty of Democrats, including "Affiliated Staff" Alice Rivlin, the former Director of the OMB in the Clinton Administration.