Photo courtesy NARA
In the Great Depression of the 1930s and '40s, laid-off U.S. workers lined up daily at employment agencies.
On November 26, 2001, it was announced that the United States was officially in a recession, and had been since March. To most Americans, this wasn't all that surprising: Rising unemployment and a weak stock market had been in the news for months.

But the announcement did raise a lot of questions. Who decides when the economy is in recession, and on what grounds? What actually constitutes a recession anyway?

In this article, we'll find out what recessions are, see why they occur, and examine the criteria economists use to identify them. We'll also look at the effects of recession as well as explore some of the ways a country can turn the economy around again.