The Washington Post Business Section's Wonkblog gives readers tips for holiday giving this year, and focuses on organizations like IPA and J-PAL that add value by increasing the public and policy-maker's understanding of what works.  As they say:

If one of the essential features of good charities is their use of good, randomized experiments to back up their methods, then it follows that groups like IPA are needed to conduct those experiments, either in conjunction with charities or on their own. So giving to IPA is a good way to indirectly promote effective charitable work by other organizations.