Measuring space: A minimum-distance database and applications to international studies

In this overview of a new database and approach to measuring distance among historical and contemporary independent nation-states, we review the utili ty of space to theory and empirical research in international studies. We i dentify weaknesses in existing empirical data on distances and contiguity a mong nations. Categorical data on distance treat proximity as an either-or issue and do not permit identifying degree of proximity among states. Conti nuous measures of distances between midpoints, such as capital cities, ofte n overstate the actual distances between state borders and suffer for large states and irregular territories. We outline a new alternative approach, b ased on measuring the minimum distance for pairs of politics in the interna tional system, which remedies some of these shortcomings. The current imple mentation of the minimum-distance database includes the minimum distances f or all politics within 950 km of each other from 1875 to the present. We de monstrate the enhanced flexibility of the new minimum-distance approach rel ative to existing alternatives. Moreover, we illustrate how variables const ructed from distance measures, combined with spatial statistical techniques , can contribute substantively to international relations and cross-nationa l comparative research. We demonstrate the importance of dependence among g eographical neighbors by examining the link between levels of economic weal th and prospects for democracy in the context of regional interdependence a mong states.