Mitt Romney says the country can afford his $5 trillion tax cut plan, and that half a dozen studies prove he’s right.

The GOP candidate insists the lost revenue from the tax cuts can be made up through the elimination of tax breaks for upper-income earners. This claim was first questioned by the Tax Policy Center, which said the tax tradeoff won’t balance out, and that Congress would have to raise taxes on lower-income Americans—by an average of $2,000—to fill the hole.

Now, The Washington Post has chimed in, reporting that the “six studies” Romney is using don’t add up.

Furthermore, only two of the six “studies” are really studies at all. Three are online articles and one is an op-ed that appeared in the Wall Street Journal.

One of the actual studies, Growth, Distribution, and Tax Reform: Thoughts on the Romney Proposal by Harvey S. Rosen of Princeton, factors in economic growth of 3% to 7% annually and assumes that deductions will be eliminated for families making $100,000 to $200,000 a year, a group that both Romney and his running mate, Paul Ryan, have shied away from punishing in their calculations.

And the author of one study, Martin Feldstein, an advisor to the Romney campaign, said that it was “impossible to calculate the exact effects of the future reforms since Gov. Romney hasn't specified what he would do.”

-Noel Brinkerhoff, David Wallechinsky

To Learn More:

The Truth about Romney’s ‘Six Studies’ (by Suzy Khimm, Washington Post)

Ryan Says Six Studies Say the Math Works in Romney Tax Plan (PolitiFact.com)

The Romney Campaign’s Job Math Is Just as Bad as Its Tax Math (by Ezra Klein, Washington Post)

The Romney Plan (Tax Policy Center)

Believe in America: Mitt Romney’s Plan for Jobs and Economic Growth (Romney for President, Inc.) (pdf)