Data, data, data . . . Economists know it well, especially when it comes to monitoring macroeconomic conditions—the basis for making informed economic and policy decisions. Handling large and complex data sets was a challenge that macroeconomists engaged in real-time analysis faced long before...

This paper shows that the explanation of the decline in the volatility of GDP growth since the mid 1980s is not the decline in the volatility of exogenous shocks but rather a change in their propagation mechanism. (JEL: E32, E37, C32, C53) (c) 2008 by the European Economic Association.