Esther Duflo, a development economist, pioneered the use of randomised evaluations to understand and fight global poverty. She is the youngest ever winner of the Nobel Prize in Economics, awarded for the substantive and methodological contributions of her scholarship and also her efforts to build a movement of evidence-based policy making for global poverty issues, a movement which has seen large shifts in how donors and governments design, implement and evaluate policies. Her research often involves iterative testing, partnership building and policy innovation as she helps guide an intervention from idea to implementation at scale. No question of relevance to global poverty is outside Esther’s domain; her scope is limited only by the feasibility of generating credible evidence to guide policy change.