Since the depths of the financial crisis in 2008-2009, most financial indicators have stabilized. However, the real parts of the economies in the industrialized world continue to lag. In this 2013 speech, I suggested that an older idea of 'secular stagnation' may help explain the disappointing recent economic performance.
Summers, Lawrence H. "Have We Entered An Age Of Secular Stagnation?" IMF Economic Review 63.1 (May 2015): 277-280.