10.3886/ICPSR05520.v1 Wallace, Michael Singer, J. David Inter-university Consortium for Political and Social Research 1984 intergovernmental organizations international affairs international agreements international cooperation international organizations memberships organizations 1984-05-03 1992-02-16 1816 1964 aggregate data, and administrative records data 5520 1 This data collection describes the membership status of 148 nations in 237 inter-governmental organizations (IGO) that were extant in the 30 five-year periods from 1815-1967. Each nation is coded at five-year intervals for membership types, such as full or associate membership in the particular IGO, and membership or nonmembership in the international system.