Is a Recession Simply a Decline in GDP? What Does That Mean?
According to the National Bureau of Economic Research (NBER), the institution that dates the peaks and troughs of the business cycles:
A recession is a significant decline in economic activity spread across the economy, lasting more than a few months, normally visible in real GDP [gross domestic product], real income, employment, industrial production, and wholesale-retail sales. A recession begins just after the economy reaches a peak of activity and ends as the economy reaches its trough.