In a recent lecture at the Center for Effective Philanthropy, Esther Duflo makes the point that aid is a relatively small proportion of all the money being spent on the poor in the world. She makes the case for thinking of spending by private donors and donor governments as like venture capitalism - an investment in finding what out works. Each dollar can then be multiplied substantially if what works can then be taken up by governments on a very large scale.

http://www.youtube.com/watch?v=oe2r_CaGhso