Mankiw henviser til en række nyere økonomiske studier, som viser at skattelettelser er langt mere potente end øgede offentlige udgifter. Og mere potent end antaget af Obama administrationen. Her er konklusionerne:
"One piece of evidence comes from Christina D. Romer, the chairwoman of the president’s Council of Economic Advisers. In work with her husband, David H. Romer, written at the University of California, Berkeley, just months before she took her current job, Ms. Romer found that tax policy has a powerful influence on economic activity.
According to the Romers, each dollar of tax cuts has historically raised G.D.P. by about $3 — three times the figure used in the administration report. That is also far greater than most estimates of the effects of government spending.
Other recent work supports the Romers’ findings. In a December 2008 working paper, Andrew Mountford of the University of London and Harald Uhlig of the University of Chicago apply state-of-the-art statistical tools to United States data to compare the effects of deficit-financed spending, deficit-financed tax cuts and tax-financed spending. They report that “deficit-financed tax cuts work best among these three scenarios to improve G.D.P.”
My Harvard colleagues Alberto Alesina and Silvia Ardagna have recently conducted a comprehensive analysis of the issue. In an October study, they looked at large changes in fiscal policy in 21 nations in the Organization for Economic Cooperation and Development. They identified 91 episodes since 1970 in which policy moved to stimulate the economy. They then compared the policy interventions that succeeded — that is, those that were actually followed by robust growth — with those that failed.
The results are striking. Successful stimulus relies almost entirely on cuts in business and income taxes. Failed stimulus relies mostly on increases in government spending.
All these findings suggest that conventional models leave something out. A clue as to what that might be can be found in a 2002 study by Olivier Blanchard and Roberto Perotti. (Mr. Perotti is a professor at Boccini University in Milano, Italy; Mr. Blanchard is now chief economist at the International Monetary Fund.) They report that “both increases in taxes and increases in government spending have a strong negative effect on private investment spending. This effect is difficult to reconcile with Keynesian theory.”
These studies point toward tax policy as the best fiscal tool to combat recession, particularly tax changes that influence incentives to invest, like an investment tax credit. Sending out lump-sum rebates, as was done in spring 2008, makes less sense, as it provides little impetus for spending or production.
LIKE our doctor facing a mysterious illness, economists should remain humble and open-minded when considering how best to fix an ailing economy. A growing body of evidence suggests that traditional Keynesian nostrums might not be the best medicine".'Se artiklen for links til kilderne.