Association for Public Policy Analysis & Management

Dual language classrooms provide English language learners (ELLs) an opportunity to receive instruction in their native language in hopes of easing the transition to English fluency, and provide an opportunity for native English speakers to receive instruction in a second language. For ELLs, learning in their native language could improve achievement by helping them build a stronger foundation in core subjects, but could also have a negative impact through delayed growth in English skills. For native English speakers, communication barriers could hurt achievement, but many argue that mental stimulation from speaking two languages leads to greater cognitive growth. Empirical testing for the effect of dual language education on academic achievement is necessary to inform the debate on the practice of dual language education, and to inform policymakers and practitioners on practices for assimilating students with non-English dominant languages.

I examine dual language education and student achievement using school choice lotteries from Charlotte-Mecklenburg School District. This paper adds to the literature on estimating causal effects of dual language education on student achievement by exploiting quasi-random assignment from oversubscribed admissions lotteries. I focus on students who applied through the district's school choice lottery for their kindergarten year, and specified a dual language school as their first choice. I use assignment to a dual language school through the lottery as an instrument for dual language school attendance to identify the local average treatment effect of dual language schooling on standardized math and reading exam scores. This paper also adds to the literature on the causal effect of dual language education on reclassification out of LEP status for language minority students.

I find local average treatment effects on math and reading exam scores of more than 0.06 standard deviations per year for participants who were eligible for English second language (ESL) services or designated limited English proficient (LEP). There is also some evidence that attending a dual language school led to a lower probability of having limited English proficient status starting in third grade. For applicants who were not eligible for ESL services or designated as LEP, attending a dual language school resulted in higher end of grade exam scores of about 0.09 and 0.05 standard deviations per year in math and reading, respectively.