A think tank or policy/research institute performs research and sometimes advocacy for topics such as social and political policy.. Think-tank funding often comes from a combination of donations from individuals and organizations/foundations, with many also accepting government grants. They publish articles, studies, reports, and sometimes draft legislation on particular policy issues. The most influential Think Tanks are listed below.
NGOs (non-governmental organizations) are influential in global issues because they often focus on social, economic, and political activities at both the community and national levels. They are usually value-based organizations that tackle issues such as: conditions of the poor, environmental protection, basic social services, and community development.
NGO examples: Amnesty International, CARE International, and Human Rights Watch.
IGOs (inter-governmental organizations) are primarily made up of sovereign states or other intergovernmental organizations that work together on issues of common interest. They are established by treaty or other charter agreement. They usually work closley with NGOs.
IGO examples: United Nations, European Union, World Bank, NATO, Organization of American States, and League of Nations.
These are generally accepted classifications. However, perception of political bias is a moving target. It is most often influenced by the study's subject, author(s), and funding. The court of public opinion never renders a permanent verdict; instead, it prefers to sway with the political winds.