This study used an age-cutoff regression discontinuity design to examine the impact of a well-resourced Early Reading First prekindergarten program designed to foster the language and literacy development of 4-year-old children from low-income homes. A special challenge for the application of the language-rich curriculum and professional development package implemented in this study was the presence of a large proportion of ELL children in essentially English-speaking classrooms. We, therefore, sought to determine whether the program was effective for improving English language and literacy outcomes for English-language learners as well as native English speakers. There were large and significant differences between treatment and control groups on literacy outcomes for all students. On the literacy tasks, ELL students in the treatment groups performed nearly as well or better than non-ELL students at the beginning of kindergarten, and reached national norms on standardized tests. There were also significant program impacts on some language outcomes for all students. ELL students who received the intervention significantly outperformed ELL students in the control groups on English receptive and expressive vocabulary. On the more complex oral comprehension skills, preschool did not have a significant impact for ELL students. Intervention effects on receptive vocabulary and oral comprehension for native speakers were found only for the third cohort and were not found for expressive vocabulary. These results provide evidence that, given material supports, coaching, professional development, and the use of a language and literacy-focused curriculum, prekindergarten classrooms can enable low-SES children from diverse language backgrounds to enter kindergarten with literacy skills at or near national norms and can significantly impact some language skills. While non-native speakers of English continued to score lower on language measures than their native-speaking peers, results show that 1 year of preschool can put all children on a positive trajectory for long-term success in school.
Early Childhood Education