A think tank is an organisation supported by donations, endowments or fees, wherein supposedly smart people "think" about new policies and write papers about them. Some of these papers end up becoming "op-ed" pieces, others become documents presented to politicians in order to influence policy. Some of them are serious research organisations with high academic standards, while others are little more than propaganda outlets.
 Types of think tanks
Non-governmental policy research institutes first started appearing in the US and several other Western countries around the start of the 20th century. They used to be firmly rooted in a progressive ethos, providing scientific foundations for policymaking. With the development of modern mass democracy, institutes that are labeled as "think tanks" nowadays fulfil a variety of roles, some of them a far cry from the original spirit, but all still connected to the field of public policy. Some of the most common forms of think tanks, as identified by James McGann, are the following:
- Policymakers - obtain their funding by doing contract research, often directly for government agencies. They usually have extensive ties to the bureaucracy, leading to an influence on policy no matter which party is in control.
- Partisans - either official research arms of political movements and parties, or at least closely affiliated. They care less about the accuracy and academic quality of their research and mostly try to influence public debates by providing their allies with talking points.
- Scholars - see themselves as nonpartisan academics and function as "universities without students". Have a strong clout in academic circles, but are less connected to policymakers. Many of the most traditional think tanks fall in this category.
- Activists - sort of similiar to partisans, but target citizens directly and try to organize popular movements in pursuit of their goals. They're often strongly associated with a single issue and focus their capabilities on it.
These categories cover most of the institutes that are active in Western societies. While Western think tanks are often part of civil society and work in pluralist, democratic systems, the same thing usually does not hold true in other parts of the world. Asia in particular has seen a boom in think tank development in recent decades, but the institutes established in countries like China are often directly controlled and funded by the state.
Donald Abelson has come up with a similar taxonomy based on the historical evolution of think tanks. He refers to the earliest think tanks as being based on the model of "a university without students" in which totally independent scholars could conduct policy research. The 1970s and '80s saw the rise of "advocacy think tanks," dedicated to producing partisan spin. Finally, there came "vanity think tanks," in which a rich donor set up a think tank for the purposes of self-promotion or as a pressure group to work on one issue.
 In the United States
- RAND Corporation (national security)
- Center for Strategic and International Studies (defense policy)
- National Bureau of Economic Research (Economics)
 Partisans and propagandists
- American Enterprise Institute (AEI) (neoconservative)
- Cato Institute (libertarian)
- Center for American Progress (progressive)
- Competitive Enterprise Institute (CEI) (libertarian, astroturfing, denialism)
- Foundation for Economic Education (FEE) (libertarian, Austrian economics)
- Heartland Institute (libertarian, denialist)
- Heritage Foundation (conservative)
- Hoover Institution (conservative)
- Independent Institute (libertarian, conspiracy theories, denialism)
- Institute for Social Research (communist)
- Ludwig von Mises Institute (LvMI) (libertarian, Austrian economics)
- Project for a New American Century (neoconservative) - defunct
- Brookings Institution (foreign policy, nonpartisan)
- Council on Foreign Relations (IR, national security, and alleged headquarters of the North American Union)
- Carnegie Endowment for International Peace (foreign and security policy)
 Activists and issue advocates
- Americans for Prosperity (AFP) (neoconservative, Teabag
- Center for Immigration Studies (xenophobic)
- Discovery Institute (Creationism, religious fundamentalism)
- Esalen Institute (New Age woo)
- International Center for Research on Women (feminist)
- Institute for Creation Research (Creationism)
- Institute for Noetic Sciences (Parapsychology)
- Tellus Institute (environmentalist)
 "Vanity" think tanks
- Center for Security Policy (Frank Gaffney's self-promotion vehicle)
- Cornwall Alliance (E. Calvin Beisner's denialist outlet)
- Science and Environmental Policy Project (S. Fred Singer's pet denialist project)
 See also
- Battle Tanks: How Think Tanks Shape the Public Agenda
- Bunkum Awards in Education
- Wiley Miller on think tanks
- Under the Influence, joint report on think tanks by NPR and The Economist
- Science by Think Tank by Massimo Pigliucci
- James McGann: The Global "Go-To" Think Tanks 2008 (PDF)
- Martin Thunert. Conservative Think Tanks in the United States and Canada. In Conservative Parties and Right-Wing Politics in North America, Opladen: Leske und Budrich 2003, 229-254.
- ↑ James G. McGann and Richard Sabatini (2011): Global Think Tanks: Policy Networks and Governance, Abingdon: Routledge.
- ↑ Think tanks must think more about issues of national interest, not self-interest, LSE Impact blog
- ↑ The name is a portmanteau of "Research and Development" (specifically of the old Douglas Aircraft Company, of which the RAND Corporation is an offshoot). Its name is not a reference to Ayn Rand, it's just an ironic coincidence.