Major shifts in the economy are rarely forecast and often not fully recognised until they have been under way for some time. So judgments about the US economy have to be tentative. What can be said is that for the first time in five years a resumption of growth significantly above the economy’s potential now appears a substantial possibility. As winter turned to spring in 2010 and 2011, many observers thought they detected evidence that the economy had decisively turned, only to be disappointed a few months later. Several considerations suggest that this time may be different.
Summers, Lawrence H. "How to Ensure Stimulus Today, Austerity Tomorrow." Financial Times, March 25, 2012.