This study is a randomized controlled trial that assessed the impact of Early College High Schools on students' high school graduation, college enrollment, and college degree attainment, as well as students' high school experiences using extant data and survey data. The study included 10 Early Colleges that enrolled students in Grades 9 to 12 in 2005 through 2011 and used a lottery for admissions, and 2,458 students who participated in those admission lotteries. The study time frame covered Grade 9 through 2 years post high school for all students and 4 years post high school for the oldest student cohort. It found that Early Colleges had positive impacts on college enrollment and college completion as well as students' high school experiences.