Update on Recession Ending in July 2009
"The NBER has not yet determined the end of the recession that began in December 2007. The date 2009-07-01 has been substituted in graphs as an estimate. This estimate is based on a statistical model for dating business cycle turning points developed by Marcelle Chauvet and Jeremy Piger (A Comparison of the Real-Time Performance of Business Cycle Dating Methods, Journal of Business and Economic Statistics, 2008, 26, 42-49). For more information, see http://www.uoregon.edu/~jpiger/us_recession_probs.htm."
The graph above shows the Chauvet and Piger recession probabilities back to January 2010 (data here). By July 2009, the recession probability had decreased to 15%, from 77.3% in June 2009, and that huge drop signalled the end of the last recession. Since August of last year, the recession probabilities have been in single-digits and falling, to only 2.8% for January 2010 (most recent month).
My UM-Flint colleague Chris Douglas also points out that the Minneapolis Fed is also using July 2009 as its estimate of the end of the recession.