A new report from the Lexington Institute, Immersion Not Submersion, Vol. III
, concludes that an emphasis on English-only teaching methods mandated by Proposition 227 is responsible for notable improvements among California’s English Language Learners, and that these methods can even overcome the effects of poverty, larger class sizes, and lower per-pupil funding. This review finds these claims to be without merit. The Lexington Institute’s report suffers from poorly sampled data, inaccurate descriptions of district-level policies, failure to account for alternative explanations for observed changes in district testing data, and lack of any serious analysis of the data presented. The report also fails to acknowledge or address recently published research studies whose conclusions are dramatically different from those presented in the report. The report is not useful for guiding educational policy or practice.