Overton Blog

Spotlight on think tanks: what is the picture in the US?

We wanted to find out what the think tank landscape looked like around the world. So, in this series we’ll use the Overton data to understand how think tanks are influencing policy, one country at a time.

There are 11,175 think tanks globally, according to the 2020 Global Go To Think Tank Index Report.

Think tanks can broadly be defined as an organisation that engages in research and advocacy on a particular topic. They have an important role in policymaking, and often act as the ‘knowledge brokers’ between university researchers and governments or other decision makers.

In this blog post, we’re exploring the picture in the US.

At the time of writing there are 464,906 documents from 254 think tank sources in the US in the Overton database.

These cover a wide range of issues but the most frequently referenced Sustainable Development Goals are:

The think tanks cited most by US policy makers are:

The US has the largest number of think tanks of any country, so unsurprisingly all of the most cited are homegrown organisations. 

NBER has more than double the number of citations as any other source, and is also heavily cited in other countries. This perhaps reflects the universality of issues like economics. A think tank like the Kaiser Family Foundation which looks at healthcare is unlikely to be heavily cited by other governments, as the US healthcare landscape is so specific. 

It’s interesting to note that while Brookings, Urban and RAND are multi-issue think tanks - which would publish on a range of topics from which the government could draw evidence - NBER and the Kaiser Family Foundation (KFF) are single issue organisations. This reflects how established and influential both these think tanks are in their respective areas, and also the amount of policy produced on these topics. Arguably the economy and healthcare are the primary policy issues in most countries, so it makes sense that think tanks focusing solely on these areas would nevertheless be cited extensively.

Again, there is a link between the most heavily cited institutions and the most prolific, though interestingly the most productive think tank in the US is not among the top five most referenced in government policy.

The think tanks producing the most publications in the US are:

Let’s take a look at some of the most cited think tanks in the US:


NBER is a think tank which conducts and disseminates economic research. It produces economic working papers, and is also known for providing start and end dates for recessions in the United States.

Their publications are referenced widely across the world - we’ve found 62,819 policy docs in the app citing them - primarily by IGOs (in which their cited in 17,555 documents) followed by source in the USA (15,834) and Germany (9,143).

Their publications are referenced in 4,648 documents from the German think tank IZA Institute of Labour Economics, followed by the World Bank (in which their work is referenced in 4,522 policy documents) the OECD (3,756) and the International Monetary Fund (3,018). Their documents on the other hand cite research from the University of Chicago, MIT and Berkeley most frequently. 

NBER’s most cited work is Trade Policy and Economic Growth: A Skeptic's Guide to Cross-National Evidence, which explores whether countries with lower policy-induced barriers to international trade grow faster. It’s been referenced in 571 other policy documents across 34 countries since its publication in 1999, including this recent document from Brussels based think tank Bruegel “A new measure of aggregate trade restrictions: cyclical drivers and macro effects”.

Brookings Institution

The Brookings Institution is a Washington based think tank whose mission is to “conduct in-depth research that leads to new ideas for solving problems facing society at the local, national and global level”. Its research focuses on a number of areas within the social sciences, including economics, governance, foreign policy, global development and climate.

Their publications are cited all over the world, though primarily in the US (with 10,920 policy docs referencing Brookings). They’re also extensively referenced by IGOs (3,787) and in policy from the UK (1,322).

Brookings are particularly influential with the World Bank, having been cited in 803 of their policy documents; the OECD who cite them in 658 documents; the House of Representatives Committees (of which there are twenty) also reference them extensively (613 policy documents) as does fellow think tank RAND Corporation (583). Interestingly, the research institutions they rely on most heavily in their own publications are broadly the same as NBER’s most cited - MIT, the University of Chicago and Berkely are also the top three more cited universities in Brookings publications.

Empirics of Growth: An Update where they try and understand the characteristics and determinants of economic growth. Cited in 203 other policy documents, including this World Bank paper Global Productivity : Trends, Drivers, and Policies (which is also extensively referenced, appearing in 104 other policy docs)

Urban Institute

The Urban Institute does research on economic and social policy issues to "open minds, shape decisions, and offer solutions". They are a multi-issue research institute and their current projects range from racial equity in education to housing stability. 

They are most cited most often in the US, appearing in 7834 policy documents, though also frequently cited in policy from IGOs (522 documents) and from UK sources (112). In terms of specific organisations, their work is very influential with OPRE (where they appear in 525 policy documents), ASPE (appearing in 407 documents) and the House of Representatives Committees 393 (of which there are twenty). Interestingly, all these bodies are government affiliated, suggesting that they are particularly influential in government circles. 

The Urban Institute’s research references Columbia University, University of Chicago, University of Michigan–Ann Arbor most often. It’s notable that all the most heavily cited think tanks in our list rely heavily on the University of Chicago in their own research. It’s not an Ivy League school, so would not be considered the most ‘elite’ and yet is very prestigious and well regarded.

Their most cited work is Where Are the Unbanked and Underbanked in New York City? which is cited in 76 other policy documents. This publication provides information on the banking status of New York residents, specifically those who operate outside the formal financial sector. This brief is referenced extensively in policy from the City of New York, including in their Social Indicators Report.


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