According to the Philly Fed's Survey of Professional Forecasters -- 51 of 'em -- the current recession started in April and will last through June 2008:
Thirty-five panelists say their forecasts reflect the influence of a new fiscal stimulus package. The size of the stimulus package is estimated at $211 billion. Out of this amount, the forecasters predict that $69 billion will go toward government consumption and gross investment, $54 billion will go toward transfer payments, and $71 billion will be used for tax cuts. According to the forecasters, the stimulus package will begin to affect real GDP growth in the first quarter of 2009. The panelists think the stimulus package will add 0.6 percentage point to the annual-average over annual-average growth in real GDP in 2009 and 0.4 percentage point in 2010.
How much are these short-term forecasts worth? This next chart suggests not much: