Reading and Language Outcomes of a Five-Year Randomized Evaluation of Transitional Bilingual Education
This study followed a group of LEP immigrant school children over a five-year period in an effort to determine whether English immersion or bilingual education produced stronger educational outcomes. No significant differences could be found, leading the researchers to conclude "that what matters most...is the quality of instruction not the language of instruction. Schools may choose to teach English language learners in either their native language or in English for many reasons, including cultural, economic, or political rationales. Yet the claims that this choice is crucial for ultimate learning of English or Spanish reading are not supported by the data from this experiment."
Slavin, Robert E., Nancy Madden, Margarita Calderón, Anne Chamberlain, Megan Hennessy. 2010. Reading and Language Outcomes of a Five-Year Randomized Evaluation of Transitional Bilingual Education. Baltimore, MD: Johns Hopkins University and the Success for All Foundation.