Assumes full employment
Diamond's study assumes the Romney tax plan is implemented under conditions of full employment. This is obviously not realistic now or for the immediate future, leading in an over-estimation of the growth-induced boost to tax revenue [UNABLE TO LOCATE THIS IN DIAMOND PAPER]
There is no apparent reference to the full employment assumption in the Diamond paper. Dylan Mathews makes the claim in the cited article, where he thanks Alan Auerbach of the University of California, Berkeley, for pointing it out.