O Estímulo Econômico de Obama Funcionou?

Ezra Klein do Washington Post faz uma resenha de 9 estudos sobre o estímulo do governo Obama:
Of the nine studies I’ve found, six find that the stimulus had a significant, positive effect on employment and growth, and three find that the effect was either quite small or impossible to detect. Five studies use econometric ”experiments,” which attempt to, as Barro encourages, sort out the effect of the stimulus from other factors using empirical data. Four use modeling instead.