A think tank, policy institute, or research institute is an organisation that performs research and advocacy concerning topics such as social policy, political strategy, economics, military, technology, and culture. Most policy institutes are non-profit organisations, which some countries such as the United States and Canada provide with tax exempt status. Other think tanks are funded by governments, advocacy groups, or businesses, or derive revenue from consulting or research work related to their projects.
The following article lists global policy institutes according to continental categories, and then sub-categories by country within those areas. These listings are not comprehensive, given that more than 6,800 think tanks exist worldwide.
According to University of Southern California historian Jacob Soll, the term "think tank" is modern, but "it can be traced to the humanist academies and scholarly networks of the 16th and 17th centuries." Soll notes that "in Europe, the origins of think tanks go back to the 800s, when emperors and kings began arguing with the Catholic Church about taxes. A tradition of hiring teams of independent lawyers to advise monarchs about their financial and political prerogatives against the church spans from Charlemagne all the way to the 17th century, when the kings of France were still arguing about whether they had the right to appoint bishops and receive a cut of their income." He also writes, independent "research teams became common in the late 16th and early 17th centuries, when states often depended on independent scholars and their expertise."
Several major current think tanks date to the 19th century. For instance, the Institute for Defence and Security Studies (RUSI) was founded in 1831 in London, and the Fabian Society in Britain dates from 1884. The oldest American think tank, the Carnegie Endowment for International Peace, was founded in Washington, D.C. in 1910 by philanthropist Andrew Carnegie. Carnegie charged trustees to use the fund to "hasten the abolition of international war, the foulest blot upon our civilization." The Brookings Institution was founded shortly thereafter in 1916 by Robert S. Brookings and was conceived as a bipartisan "research center modeled on academic institutions and focused on addressing the questions of the federal government."