LAUSR

Informal intergovernmental organizations (IIGOs) such as the Proliferation Security Initiative and G20 increasingly play a central role in governing international relations. IIGOs are based on recurrent meetings among high-level state representatives but are not legalized through a treaty and have no permanent secretariat. They allow states to organize internationally without sacrificing autonomy to a supranational entity. We present the IIGO 2.0 dataset, the most comprehensive compilation of these institutions to date, and illustrate the significance of IIGOs through several key empirical findings. First, while the creation of formal IGOs (FIGOs) has plateaued, states are increasingly creating IIGOs to address critical global issues. Second, states disproportionately use IIGOs for high politics issue areas including peace, security, and political agenda-setting which challenges conventional wisdom that IGOs (intergovernmental organizations) are less relevant in the security realm. Third, IIGOs are remarkably durable. Although states could readily formalize or abandon IIGOs, they generally organize cooperation informally for long periods. Finally, IIGOs are typically smaller than FIGOs and this design choice is increasingly used by states of all levels of development, power, and region. The availability of the IIGO 2.0 dataset will promote further analysis on the growing diversity of international institutions.