Two-way dual language (DL) classrooms enroll students of two different language backgrounds and teach curriculum in both languages. I estimate the effect of attending a dual language school on student achievement using school choice lotteries from Charlotte Mecklenburg School District, finding local average treatment effects of 0.04 and 0.05 standard deviations per year in math and reading, respectively. Attending a DL school increased test scores for English learners (ELs) and for non-ELs by a similar magnitude. The positive effects of winning the lottery to attend a DL school are substantially larger than the average effect of assignment to other magnet schools, and several peer and school characteristics are ruled out as explanations for the increased test scores. There is no statistically significant evidence that attending a dual language school changed the probability of having EL status throughout elementary school.

中文翻译：

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双语教学与学生成就

双向双向语言（DL）教室招收具有两种不同语言背景的学生，并以两种语言教授课程。我使用夏洛特·梅克伦堡学区的择校彩票来评估就读双语言学校对学生成绩的影响，发现每年在数学和阅读方面的本地平均治疗效果分别为0.04和0.05标准差。进入DL学校，英语学习者（EL）和非英语学习者的考试成绩提高了相似的程度。赢得彩票以进入DL学校的积极影响远远大于分配给其他磁铁学校的平均影响，并且排除了一些同龄人和学校的特征作为增加考试分数的解释。