The Geometry of the Distance Coefficient in Gravity Equations in International Trade
Review of International Economics
Published online on July 20, 2016
Abstract
Gravity equations in trade imply that trade flows are proportional to the size of a country and inversely proportional to distance. This paper develops the analogy of gravity in physics with gravity in trade and provides geometric intuition for a large class of mathematical processes in two‐dimensional space for which these relationships would be expected. This model implies that distances between countries in empirical gravity estimations should be measured as weighted harmonic means of pairwise distances of local economic activity.