Officially, the recession started in 2007.  But at the Freakonomics blog, Justin Wolfers asks us to consider whether it may have started a bit earlier.  And he shows us this:

Wolfers:

The blue line is the usual measure of GDP, which is obtained by adding up total spending. When you read the newspapers, this is the number they report. But the Fed’s Jeremy Nailewaik has convincingly shown that red line—which is the sum of all income—is the more reliable measure.  In theory the two lines should be identical—one person’s spending is another’s income—but in practice, the measurements differ. I’ve also plotted the peak, trough, and latest reading of each measure.

Focus on the red line, and you’ll see that the recession began in the final quarter of 2006, not the end of 2007. The red line also fell by more, and over a longer period. And today, GDP remains below its levels nearly five years ago. The economy had already run out of steam halfway through Bush’s second term. That’s why I say we are halfway to a lost decade.

And he gets more granular in the analysis.  Read We’re Halfway to a Lost Decade here.