The following definition served as a basis for discussions during the first book project on the governance of international institutions:
“We understand the term “international institutions” broadly, comprising various formal and informal entities. In many cases international public authority is vested in an institution that qualifies as an international organization with international legal personality. However, the research on global governance reveals that there are other institutions exercising public authority as well. Some treaty regimes, for example CITES, or informal institutions, such as certain committees within the remit of the OECD, or the G8, are creatures of states which wield considerable political clout and whose acts raise concerns of legitimacy. These are institutions in the sense of organizational sociology, though they might not have legal personality akin to an international organization. Moreover, even in policy areas where there is a competent formal organization, public authority can be exercised through more or less informal bodies associated with it, but legally external to it, such as networks of domestic administrators. This broad concept of international institutions is based on the empirical insight that many of the more informal and more difficult to characterize organizations operate largely as the less legalized brethrens of formal organizations.”