Question: political orientation of think tanks and policy orgs

Hi, yep I'm a student -- library and info studies no less -- but am stumped on this one and figure you can help. Is there a site where one can get reliable information about the political orientation of various think tanks and generically-names groups and organizations? Right now I'm particularly interested in the National Bureau of Economic
. I've been to their "About" page and know I can do indiv. research on some of the Board members and so on, but I'm looking for a shortcut ... a more comprehensive list of orgs that can be searched on...

Here's a list of these kinds of sources, but are any of them better than the others?

any info or insight you can provide is much appreciated.