- ESL placement in high-immigrant concentration schools appears to improve immigrant achievement.
- In high immigrant concentration schools, second-generation students derive the greatest benefit from ESL placement.
- The effect of ESL placement depends not only on the school context and individual generational status but also on the interaction between the two.
- Some negative estimated effects of ESL placement might be due to the social and institutional marginalization of students into certain courses, especially in low-immigrant-concentration schools.