Esther Duflo discusses the fact that in social policy one cannot check the big questions, i.e. whether development assistance as an aggregate is helpful, because there is no counterfactual. She then suggests to focus on smaller questions such as what prevents or incentiveses people from immunizing their kids or whether mosquito bednets should be distributed for free. These questions can be answered by using randomized control trials as in the medical sciences. Thus, she argues, by bringing the experimental method to social policy analysis better decisions as to where allocate funds can be made.