Two Harvard Kennedy School research centers have been recognized as among the best think tanks in the world.

The Belfer Center for Science and International Affairs is ranked number one and the Center for International Development (CID) as the third best university-related think tank in the 2011 Global Go To Think Tanks Index, released on Jan. 19 by the Think Tanks and Civil Societies Program at the University of Pennsylvania.

“We are very pleased that the Penn survey has acknowledged the impact of the Belfer Center and other university-based think tanks,” said Graham Allison, director of Harvard Kennedy School’s Belfer Center for Science and International Affairs. “And we are especially proud to be recognized for engaging policy makers effectively in our core areas of security and international relations.”

The rankings are the culmination of an eight-month process involving almost 800 expert panelists, 150 journalists and scholars, and 120 academic institutions.

More than 30 distinct rankings are included in the 2011 report, including those based on region, area of research, and special achievement.

The Belfer Center takes the top spot in the university-affiliated think tank rankings. It is also ranked 25th among all think tanks in the United States and 17th on the list of security and international affairs think tanks globally. CID is ranked third on the university-related list. It is also rated 19th among all U.S. think tanks and fourth on the list of international development think tanks.

The report’s author, James G. McGann, director of the Think Tanks and Civil Societies Program in the University of Pennsylvania’s International Relations Program, notes the critically important role that think tanks play in the 21st century.