Assessing legitimacy of informal intergovernmental organizations in the context of changing multilateralism

Abstract This article seeks to contribute to the literature by investigating the legitimacy of informal intergovernmental organizations (IIGOs) based on the six identified criteria and by understanding the impact of 94 active IIGOs on diverse issue areas within the realm of multilateralism. It introduces an innovative framework grounded in six specified legitimacy criteria derived from six hypotheses: 1) IIGOs' selected policy areas (economic, political, security or social affairs); 2) bureaucratic structure; 3) economic development level of member states; 4) geographical distribution of members between the global North and the global South; 5) pursuance of proactive diplomacy within formal intergovernmental organizations; and 6) the capacity of IIGOs for norm creation and diffusion. In our study, we aim to uncover the extent to which IIGOs exhibit high, moderate or low levels of legitimacy based on the six legitimacy criteria. Contrary to the prevailing belief that IIGOs, owing to their informal and flexible nature, do not require strong bureaucracies, our research unveils that more than 40 per cent of the IIGOs assessed exhibit a high level of institutionalization. Our research reveals that the robust bureaucratic structures of IIGOs positively influence their legitimacy scores, and that the overall legitimacy of an IIGO necessitates a high level of both sociological legitimacy and normative legitimacy.