The open secret of the economics profession is that its practitioners don’t have a theory for why expansions die. Or rather they have several theories, each of which contradicts the others and none of which is fully supported by the data. Because economists don’t know why recessions start, they can’t predict when one will start.
The likelihood is that the U.S. economic expansion that began in June 2009 will reach its 10th birthday this summer and roll right on, becoming the longest U.S. period of uninterrupted growth since at least 1854