The document discusses three randomized controlled trials that evaluated the use of mobile phones in adult education programs in Niger and the United States. In Niger, one trial provided mobile phones to students in an adult literacy program to test if the phones could serve as an educational tool by allowing students to practice reading, writing, and math skills on their own. A second trial in Niger used mobile phones to monitor literacy teachers' attendance and improve accountability. The third trial in the US examined if mobile phones could serve as a substitute for in-person teachers for certain types of learning. The document provides context on the adult education interventions in Niger and discusses the goals and research questions of using mobile phones in education.