Global price dispersion: are prices converging or diverging?

This paper documents significant time-variation in the degree of global price convergence over the last two decades. In particular, there appears to be a general U-shaped pattern with price dispersion first falling and then rising in recent years, a pattern which is remarkably robust across country groupings and commodity groups. This time-variation is difficult to explain in terms of the standard gravity equation variables common in the literature, as these tend not to vary much over time or have not risen in recent years. However, regression analysis indicates that this time-varying pattern coincides well with oil price fluctuations, which are clearly time-varying and have risen substantially since the late 1990s. As a result, this paper offers new evidence on the role of transportation costs in driving international price dispersion.