Just how much additional growth does a stimulus package buy you? (1.65 x stimulus) – 2.1, apparently, where stimulus is a percentage of GDP. (Example – a stimulus measuring 3 per cent of GDP should produce growth that is 2.85 per cent above expectations.)
Policymakers would hope that spending relatively more stimulus would bear some fruit. And so it appears from the Economic Report of the President.

Chart found on p.105. Please note the power of stimulus to explain above-forecast growth is quite low (R² = 0.31), and the data is taken at a very specific snapshot – November forecasts and Q2 results. Results for Q3 results were not statistically significant.
There is a twist, however. Middle-of-the-road stimulus spenders did not receive expected levels of benefit – and they include the US, UK and Canada, well below trendline in the scatterplot. It seems fortune favours the brave.

And country-by-country figures: Read more