On the Sources of the Great Moderation

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 re‡ected in both conditional and unconditional second moments as well as in the impulse responses to identi…ed shocks. That evidence points to structural change, as opposed to just good luck, as an explanation for the Great Moderation. We use a simple macro model to suggest some of the immediate sources which are likely to be behind the observed changes.