English-language learners assigned to dual-language-immersion classrooms in the Portland, Ore., school district were more likely to be classified as English proficient by 6th grade when compared to peers enrolled in traditional classes, a new study by the RAND Corp. found.
The research team also determined that the district’s dual-language students significantly outperformed their ELL who were not in dual-language classes peers on English-reading skills—by nearly a school year worth of learning by the end of middle school.
Those are two of the key findings of a four-year, randomized trial of the district’s dual-language program by RAND, along with the the American Councils for International Education, and Portland schools.
Researchers compared students who were randomly assigned to the immersion programs to those who had applied unsuccessfully for the lottery. That allowed researchers to run a randomized trial of about 1,600 students who started kindergarten between the fall of 2004 and fall of 2010.
The study included programs that represented four different partner languages: Spanish, Japanese, Mandarin Chinese, and Russian. The random-assignment process allowed the study to estimate effects caused by access to these programs and not by the characteristics or preferences of families who chose dual-language instruction.
The students who participated in the immersion programs scored significantly higher on the Oregon Assessment of Knowledge and Skills in reading; by the equivalent of seven months of learning by the end of 5th grade and by nine months of learning by the end of 8th grade. The research team found no benefit, but also no negative effect, on immersion students’ scores in math or science. Education Week’s Inside School Research blog first reported on the preliminary conclusions of the RAND study two years ago.
The findings are consistent with other research that touts the benefits of dual-language instruction. That body of research includes a 2015 Rice University study that determined that English-learners in the Houston schools have more success learning English when they’re enrolled in dual-language programs that include native-English speakers in the classroom.
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