Countries have better abilities and stronger incentives to engage in militarized conflicts the larger and more powerful they are. The article applies Zipf's notion of a ``gravity model'' to the risk of interstate conflict and argues that the empirical relationship between size and distance and...

The gravity model of trade states that the volume of trade between two countries is proportional to the product of the sizes of the two countries and the inverse of the distance between them. The gravity model, however, was initially suggested for other types of social interactions, and it also...

Two studies question whether economic interdependence promotes peace, arguing that previous research has not adequately considered the endogeneity of trade. Using simultaneous equations to capture the reciprocal effects, they report that trade does not reduce conflict, though conflict reduces...