While the importance of using data and evidence has been highlighted in international development to enhance the effectiveness of projects and programs, it has not been sufficiently discussed how data and evidence are used effectively. This presentation discusses how a development agency can use data and evidence to improve and expand its development programs, taking the example of the Indian NGO Pratham. In a series of experiments with researchers, Pratham developed and refined their learning agenda to search for a better strategy to improve children’s foundational learning. Pratham has also regularly conducted a nationwide survey on children’s foundational learning. Data from the nationwide survey demonstrated the problem in children’s foundational learning, and evidence from experiments showed an option for an effective strategy to address it. The search, learning, and communication cycle using data and evidence, conceptualized from the case of Pratham, would enhance the effectiveness of development agencies to support educational development better. This presentation further discusses how Pratham collects and uses the assessment and monitoring data in their programs. The case of Pratham indicates several principles for development agencies to use data to better manage their program and improve practices.