Gravity with Granularity

Organised by

• Department of Economics

Abstract:

This paper demonstrates that the estimation of gravity equations of trade flows suffers from an omitted variable bias when firms are granular and behave oligopolistically. We show how to correct for this bias in the estimation of both firm- and industry-level gravity. Using French and Chinese export data, we find that the oligopoly bias leads to a substantial underestimation of the effects of distance on trade flows. In a calibrated version of the model, the welfare gains from a trade liberalization are found to be almost twice as large under oligopoly as under monopolistic competition.