Arianna Legovini is the Director of the Development Impact (DIME) department at the World Bank. She created the DIME model to transform the way data and impact evaluation evidence is generated and channeled into policy action. The approach increases the returns to development projects by wide margins. The model is based on an iterative process of evidence-informed adaptive change. In the DIME model, demand for data and impact evaluation research is created by putting clients first, releasing their financial and technical constraints, building capacities, and generating contextually relevant and highly influential evidence. She forged alliances with senior management and donors on knowledge priorities and case selection, raising $220M in IE research financing, to help shape the design of $22 billion in development finance. She restructured the production of impact evaluation research from piecemeal to programmatic to optimize economies of scale, introducing specialized administrative, review and data services to increase technical quality. Instituting strict procedures for research technical standards, ethics, transparency, reproducibility and data privacy and security, made DIME a global leader in research quality and credibility, through the provision of open-source tools and training for the global research community. She attracted exceptional talent to her team, aligning incentives to spur innovation, teamwork and high impact public goods, and fostering diversity and equal representation of women, and their intellectual contribution, to research. She serves as a senior adviser to a score of multilateral and bilateral agencies and collaborates with more than 300 institutions around the world.