Bilingual education: Another look at the research

Sent to the OC Register, Oct 22.
Aaron Smith ("The fight over English-only education highlights the need for school choice." Oct. 21) claims that English learners' test scores "shot up" after bilingual education was dismantled by Prop. 227 in 1998.  But test scores increased for ALL students in California, not just English learners: A new version of the Stanford 9 test was introduced the year before the English-only law was passed. Scores increased each year as students and teachers became more familiar with the test, a well-documented pattern when new standardized tests are introduced. Research has shown no obvious improvement in English language development resulting from the passage of Prop. 227.
Smith also claims that research shows that bilingual education is neither a failure nor a success. But controlled scientific studies have consistently shown that students in bilingual programs outperform students with similar backgrounds in all-English programs on tests of English. In the most recent analysis, Professors Grace and David McField concluded that when both program quality and research quality are considered, the superiority of bilingual education was considerably larger than previously reported.
Stephen Krashen

original article: http://www.ocregister.com/articles/made-733003-ago-voters.html
Well-documented pattern: Linn, R., Graue, E., and Sanders, N. 1990. Comparing state and district test results to national norms: The validity of claims that “everyone is above average.” Educational  Measurement: Issues and Practice 10: 5-14.
No obvious improvement: Parrish, T. et. al. 2006. Effects of the Implementation of  Proposition 227 on the Education   of English Learners, K–12, American Institutes for Research and WestEd.
Controlled scientific studies: McField, G. and McField, D. 2014.  "The consistent outcome of bilingual education programs: A meta-analysis of meta-analyses." In Grace McField (Ed.) The Miseducation of English Learners. Charlotte: Information Age Publishing. pp. 267-299.
Previous meta-analyses of bilingual education research (all conclude that bilingual education is more effective than English immersion)
Greene, J. (1999). A meta-analysis of the Rossell and Baker review of bilingual education research. Bilingual Research Journal, 21 (2,3): 103-122.
Rolstad, K., Mahoney, K., & Glass, G. (2005). The big picture: A meta-analysis of program effectiveness research on English language learners. Educational Policy 19(4): 572-594.
Slavin, R. and Cheung, A. (2005). A synthesis of research of reading instruction for English language learners, Review of Educational Research 75(2): 247-284.
Willig, A. (1985). A meta-analysis of selected studies on the effectiveness of bilingual education. Review of Educational Research 55(3): 269-317.