From the Website: "Think Tank Search searches the websites of institutions that generate public policy research, analysis, and activity. These sites are affiliated with universities, governments, advocacy groups, foundations, and non-governmental organizations. Inclusion is based upon the relevancy of subject area to HKS [Harvard Kennedy School] coursework and scholarship, the availability of the think tank's research in full-text on the website, and the think tank's reputation and influence upon policy making. The list represents a mixture of partisan and non-partisan think tanks."
Harvard Kennedy School Library & Knowledge Services
Harvard Library Research Guides: https://guides.library.harvard.edu/