Not surprisingly, the long expansion has raised questions about the whole notion of the business cycle. Extended periods of expansion always lead a few commentators to speculate that the conventional business cycle is dead. With two record-setting expansions in a row, and the current one still going, it is to be expected that the notion of regular business cycles is again being questioned. These changes reflect real changes in the U.S. economy, changes in our ability to measure economic developments, and changes in economic theory. The NBER is a private, non-profit research organization whose research affiliates include many of the world's most influential economists.
Recessions are, therefore, macroeconomic in nature.
A severe decline in an important industry or sector of the economy may involve great hardships for the workers and firms in that industry, but a recession is more than that. It is a period in which many sectors of the economy experience declines. Recessions are sometimes said to occur if total output declines for two consecutive quarters. Business cycle peaks and troughs cannot be identified immediately when they occur for two reasons. First, recessions and expansions are, by definition, recurring periods of either decline or growth.