Prior to 2007, several economists noted that the volatility of output growth and output inflation had declined dramatically since the mid 1980s and that only two minor recessions had occurred in the U.S. A debate started to explain the causes of the long period of stability. Some authors argued that structural changes had occurred in the economy while others emphasized the role of improved monetary policy. Stock and Watson (2002, 2005) provide a summary of the debate and named the period the “Great Moderation,” a name later endorsed in a speech by then Vice-Chairman Bernanke (2004). Stock and Watson concluded that most of the stability of the Great Moderation was attributable to unexplained factors instead of improvements in the structure of the economy or in monetary policy; luck was the main cause of the Great Moderation.