The National Bureau of Economic Research, the non-partisan group of economists that determines economic cycles, today officially announced that the United States began a recession in December 2007. The official announcement always arrives in a belated manner because the nature of the data only permits economists to analyze and recognize a recession after it has begun. This may seem like just a semantic technicality, since most people already acknowledge that the United States is in a recessionary period. However, the NBER is the group that makes the designation official. Therefore, there can no longer be any debate about whether it is a fact. It is a fact!
Here is a story on Forbes about the announcement.