Some of my favorite assumptions behind the White House's estimate of 3.5 millions jobs being saved or created:
For every two jobs directly created by the stimulus spending, a third job will be indirectly created. The 2-to-1 ratio is rough and varies considerably by sector. A tax cut has only one-quarter of the value of a spending increase of the same size, in terms of expanding the economy. Every dollar spent on unemployment benefits is worth $1.63 of quick economic expansion. Food stamps boost the economy even more.
What planet are these people living on?!