While there is increasing evidence that enhancing the communication between schools and parents significantly improves students’ performance, less is known about what mechanisms drive those effects. Is it because communication primarily alleviates the moral hazard problem between parents and children, by providing parents with information about attendance and grades? Or is it because because parents have limited attention, and communication makes parenting “top of mind”? We randomly assign communication interventions at the school and student levels, within a sample of Brazilian public schools, in order to estimate the impacts of each of those mechanisms on parental engagement and students’ outcomes. Our design also allows investigating how different mechanisms interact. Results are forthcoming.