A think tank is a research institute or organization employed to solve complex problems or predict or plan future developments, as in military, political, or social areas.
An IGO is an organization composed primarily of sovereign states, or of other intergovernmental organizations. IGOs are established by treaty or other agreement that acts as a charter creating the group.
A non-governmental organization (NGO) is any nonprofit, voluntary citizens' group which is organized on a local, national, or international level. Task-oriented and driven by people with a common interest, NGOs perform a variety of service and humanitarian functions, bring citizen concerns to governments, advocate and monitor policies, and encourage political participation through provision of information.
