The NBER determined that the U.S. economy peaked in March 2001, and has been in recession since.
The NBER examines four variables:
manufacturing and trade sales
In this current recession these four indicators are pointing in different directions. This is not a usual recession--where all of the major indicators show that a business cycle peak has been reached within a very few months of each other.
Sales reached a peak in August of 2000.
Industrial production has been declining since September 2000.
Employment has been declining since March 2001.
And incomes continue to rise.
This time, therefore, any dating of the business cycle peak and the recession is exceptionally hazardous.
Indeed, the failure of the major indicators to show their standard business cycle-peak pattern raises questions about whether "business cycle theory" provides a good way to understand what is going on.