Conversable Economist: The Potential GDP Perspective on Business Cycles
A few themes jump out from looking at the data in this way:
1) If the Great Recession is measured according to how far the economy had fallen below potential GDP, it is actually quite similar to the effects of the double-dip recession in the early 1980s.
2) If the Great Recession is measured by the size of the drop, relative to potential GDP, it is about 9 percentage points of GDP (from an actual GDP 1 percent above potential GDP to an actual GDP that is 8 percent below potential GDP). The total size of this drop isn't all that different--although the timing is different--from the years around the double-dip recession of the 1980s, the years around the recession of 1973-75, and the recession of 1969-1970.
3) The recovery from the early 1980s recessions was V-shaped, while the recovery from the Great Recession is more gradual. But this change isn't new. The recoveries from all the recessions before the early 1980s were reasonably V-shapes, and the recoveries after the 1990-91 and 2001 recessions were more U-shaped, as well.
Here is the Graph he references: