International subsystems, 1649-1963

There are three distinct sets of data related to this study of the structure of the international system and its consequences for national war behavior. In one set, twenty-one subsystems constitute the unit of observation, with variables recording the number of members, the number of wars, alliances, and polarity of each subsystem. In a second set of 457 cases, each member of each subsystem is the unit observed, and national characteristics are reported. A third set reports the war behavior of each of the twenty-one subsystems, with one record for each war as reported in four major studies of war participation: Lewis F. Richardson, Statistics of Deadly Quarrels, Quincy Wright, A Study of War, Pitrim Sorokin, Social and Cultural Dynamics, and J. David Singer and Melvin Small, Wages of War.