The New York Times writes there is no official definition of a recession, and no official body to announce when one starts or ends. Still, recessions are often described as two or more quarters of a declining gross domestic product (GDP).
The National Bureau of Economic Research, a private, non-partisan group based in Cambridge, Mass., does not define a recession based on declining GDP.
“Rather, a recession is a significant decline in economic activity spread across the economy, lasting more than a few months, normally visible in real GDP, real income, employment, industrial production, and wholesale-retail sales.” – National Bureau of Economic Research
The NBER says the latest recession began December 1, 2007 and ended in June 2009.