With funding from the Robert Wood Johnson Foundation, Child Trends is working with the Children’s National Health System, Boston Children’s Hospital, and Temple University, to conduct a multi-phase, multi-year evaluation of the impact of school start time changes in a diverse suburban school district. The current project focuses on collecting baseline survey data from students in grades 7 to 12, as well as their parents. Sleep actigraphy and daily diaries are also being collected from a random subsample of the participants. Potential outcomes include changes in sleep duration and quality, BMI, depression, academic achievement, and school climate.