This report is part of the Independent Evaluation Group’s (IEG) impact evaluation series. These studies fit under the category of “rigorous, but relevant” evaluations, seeking to use a variety of data sources, both to demonstrate impact and deliver policy relevant conclusions. This study is the first of the impact evaluations to combine evidence from a number of different countries; it uses data from a range of sources, both existing studies and re-analyses of existing survey data. Although the report touches on aspects of sector performance, it does not claim to be a comprehensive sector review.