The University of Pennsylvania is about to release its annual index of the world's top think tanks. The release will take place January 17, 2013 at the World Bank (morning) and the United Nations University (afternoon).
The report will be released by Dr. James McGann, Assistant Director of the International Relations Program, and Director of the Think Tanks and Civil Societies Program, at the University of Pennsylvania.
Here is a flyer from the World Bank about the event.
The latest report ranks 6,500 think tanks. Here are the 2011 rankings which were released January 2012.