Stimulus spending actually harms the economy. This is pretty well known. Econ 101, as Kevitivity might say.
Let's take a look at the inputs to GDP.
GDP = C + I + G + X - M
Or, in plainer terms, GDP is equal to total Cuts in government services for the period, plus top percentile Income, plus Government paydown of debt, plus taX cuts, minus total Mouths on the government teat, i.e. welfare recipients.
You can see that stimulus spending affects several of these inputs. It decreases C because it raises rather than cuts government services, that's a negative. It has little to no effect on top percentile income. It decreases G by causing a rise in government debt rather than a paydown, another negative. And it increases M, the number of people on welfare, a third negative since that's subtracted. It can potentially increase X if it's in the form of a tax cut.
You can see that the only acceptable form of stimulus is a tax cut on the highest earners combined with a cut on government spending, as that increases C, I, and X. Though it also decreases G, which is why a tax cut stimulus isn't always effective.
And thus we see that Obamacare's "stimulus" richly deserves the scare quotes: it actively harms GDP, and all it really stimulates is popular sentiment against deserving job creators, by promoting class warfare.
Plus most of the "stimulus" went to Solyndra.