In this poster presentation, the authors examine the impact of Chicago School Readiness Project (CSRP) on students' academic achievement in elementary school. First, they provide upper- and lower-bound estimates of the impact of CSRP on students' academic achievement, taking into account their subsequent nonrandom selection into higher versus lower quality school settings. Second, they test whether estimates of treatment impact vary as a function of key child (e.g., behavioral and poverty-related risk) and school characteristics (e.g., lower school quality in more highly disadvantaged neighborhoods). Third, taking a comprehensive view of children's development, and controlling for treatment status, they examine the extent to which classroom, family, and child characteristics, including more adaptive approaches to learning (e.g., on task behavior), shapes students' academic achievement. (Contains 2 tables.)