Microcredit is the most visible innovation in anti-poverty policy in the last half-century, and in three decades it has grown dramatically. With more than 200 million borrowers,1 microcredit has undoubtedly been successful in bringing formal financial services to the poor. Many believe it has done much more, and that by putting money into the hands of poor families (and often women) it has the potential to increase investments in health and education and empower women. Skeptics, however, see microcredit organizations as extremely similar to the old fashioned money-lenders, making their profits based on the inability of the poor to resist the temptation of a new loan. They point to the large number of very small businesses created, with few maturing into larger businesses, and worry that they compete against each other. Until recently there has been very little rigorous evidence to help arbitrate between these very different viewpoints.