We estimate a dynamic two-country model in which economic fluctuations are driven by a worldwide supply shock, country-specific supply shocks, and relative fiscal, money, and preference shocks. Identification is achieved using only long-run restrictions, based on a theoretical model. The main results, are: (i) supply shocks, particularly country-specific ones, are very important in generating international business cycles, (ii) although the post-1973 flexible-exchange-rate period has been inherently more volatile, there are no differences in transmission properties of economic disturbances across exchange-rate regimes for the endogenous variables we focus on.

The volatility of U.S. real GDP growth since 1984 has been markedlylowerthanoverthepreviousquartercentury.Weutilizefrequency-domain and VAR methods to distinguish among competing explanations for this reduction: improvements in monetary policy, better business practices, and a fortuitous reduction in exogenous disturbances. We find that reduced innovation variances account for much of the decline in aggregate output volatility, suggesting that good luck is the most likely explanation. Good practices and good policy appear to have played a more important role in explaining the post-1984 decline in the volatility of consumer price inflation.