Aggregate Fluctuations with National and International Returns to Scale*

Abstract

Cyclical movements in aggregate output, factor inputs, and productivity are all positively correlated across countries. This article proposes a model in which positive cross‐country correlations of these variables result from increasing returns to the world‐wide variety of intermediate goods even if technology shocks are purely country‐specific. The model also accounts for the observed positive relationship between bilateral trade volume and international comovements. Positive comovements can also arise with constant returns to variety, but only if technology shocks are themselves strongly correlated. The combination of constant returns and common shocks, however, tends to generate procyclical fluctuations of the trade balance.