From Senate Republican Policy Committee:

CBO says stimulus bad for the economy: CBO on Wednesday released an analysis that estimates the impact the Senate’s $1.3 trillion bill will have on the American economy. Ahem: “In the longer run, the legislation would result in a slight decrease in gross domestic product (GDP) compared with CBO’s baseline economic forecast.” In the short run, it will create between 1.3 and 3.9 million jobs and add 1.2 to 3.6 percentage points to GDP, but “the effects of the legislation would diminish rapidly after 2010” and in the long run it will lower aggregate output (GDP) by 0.1 percent to 0.3 percent.
Note this is nominal output, so if there is any inflation whatsoever over the next ten years (and as George Mellon points out in the Wall Street Journal it is hard to imagine there won’t be) the economy could be significantly worse off after ten years of massive deficits due to the effects of massive government borrowing “crowding out” private investment. CBO: “Including the effects of both crowding out of private investment (which would reduce output in the long run) and possibly productive government investment (which could increase output), CBO estimates that by 2019 the Senate legislation would reduce GDP by 0.1 percent to 0.3 percent on net.”