Greg Mankiw, New Keynsians and Dynamic Scoring

Greg Mankiw is one of the more interesting economists around. He is known in the field as one of the leading exponents of “new-Kenysianism.” These are folks who believe that the macroeconomy occasionally suffers from large-scale failure and that government intervention is occasionally necessary to put the economy back on track. Unlike old-Keynsians, however, new-Kenysians are not single-mindedly fixed on aggregate demand shortfalls. Many largely accept the lessons of the “new classical” and “real business cycle” schools of thought and believe that fluctuations in both aggregate demand and aggregate supply determine the economy’s path.
In my mind, the single most important contribution of new-Keynsian analysis was to provide microeconomic theoretical and empirical justification for the notion that occasionally prices and wages do not move as fluidly as might be ideal. This seems far more realistic than the mathematically-precise but unrealistic assumptions which dominated the profession for so long.
One of the most interesting things to note about the new-Keynsians, though, is their ideological diversity. As one might expect, their ranks include a number of old-style Kenysians who prefer that government take an active role in the economy. These are folks like David Romer and Joseph Stiglitz. They also include a number of relatively free-market economists, however. And in this camp, one must surely put Greg Mankiw and the new fed chair Ben Bernanke.
Mankiw, of course, recently served a stint as President Bush’s economic advisor. He has a new blog here which is very readable and very interesting. He also has a forthcoming article with Weinzierl in the Journal of Political Economy. In it, he finds empirical justification for “dynamic scoring,” the old supply-side notion that when you estimate the impact of a tax cut on treasury revenues, you should account for whatever boost the cut will provide the economy. While tax cuts hardly pay for themselves (sorry conservatives), they do find that 17 percent of the revenue loss from a reduction in labor taxes is recouped by the treasury because of greater economic activity. Moreover, fully 50 percent of the revenue loss form a cut in capital taxes is recouped. Personally, I think tax cuts are good for their own-sake, irrespective of their impact on the treasury. Still, this is a powerful refutation for those who say that tax cuts will bankrupt the government.