Citerank: (9) 231226Obamacare inclusionThe revenue baseline is inflated. The TPC included in its baseline Obamacare taxes which Romney has not pledged to offset. This point is conceded by some defenders of the TPC analysis such as Josh Barro (see citation).13EF597B, 231236Life insurance concessionsSome TPC defenders are prepared to concede this one could be back on the table.1198CE71, 231238Savings overstated13EF597B, 231460A different planA tax proposal which deemed income above $100,000 high is a different proposition from the one Romney has actually advanced which aims to shield earners below the $200,000 threshold.13EF597B, 231564Assumes acrrued gains taxed on deathBarro says Dubay gets it wrong on the revenue gain from moving to a carry-over basis. This is because the OMB estimate that Dubay relies on presumes gains would be taxed on an accruals basis immediately upon death, as stated in a footnote (see citation).13EF597B, 231567Revenue baseline understatedAccording to one critic Rosen failed to include in his estimate of the revenue that would need to be generated from base-broadening allowance for Romney's proposals to repeal the Estate Tax and Alternative Minimum Tax.1198CE71, 231568Micro-behavioral offsetsOne of the authors of the TPC analysis argues that Rosen expects taxpayers to adjust their behavior to rate cuts, but fails to do so in a symmetrical fashion for reduced tax concessions. These would offset revenue gains from the former.1198CE71, 232174Micro-behavioral offsetsOne of the authors of the TPC analysis argues that Rosen expects taxpayers to adjust their behavior to rate cuts, but fails to do so in a symmetrical fashion for reduced tax concessions. These would offset revenue gains from the former.1198CE71, 233432Broadening effectsThe authors state they have not included in their model any estimation of the effects of base broadening - since these have not been specified by Romney. But this presumes they have no bearing on incentives. One of the TPC authors raised this in response to Rosen (see citation below)13EF597B

This is for two reasons. First, TPC's thought experiment -- eliminate as many deductions as possible at the top while holding those below $200,000 harmless from tax increases -- was not only exceedingly generous in granting Romney's assumptions. It was impossibly generous. Under the terms analyzed by the TPC study, a taxpayer earning $199,999 would face a drastically higher tax bill for earning $1 more in income. That doesn't happen in the real world.

Instead you would need to phase in restrictions in deductions on the wealthy, which would reduce the amount of revenue those restrictions generated. Harvard Professor Martin Feldstein, in one of the analyses cited by the Romney campaign, makes a rough estimate that a phase-in would cost about $15 billion. My back-of-the-envelope calculations roughly match that.