"The remarkable decline in macroeconomic volatility experienced by the U.S. economy since the mid-80s (the so-called Great Moderation) has been accompanied by large changes in the patterns of comovements among output, hours and labor productivity. Those changes are reflected in both conditional...

"We construct a utility-based model of fluctuations, with nominal rigidities and unemployment, and draw its implications for the unemployment-inflation tradeoff and for the conduct of monetary policy.We proceed in two steps. We first leave nominal rigidities aside. We show that, under a standard...