Research validating sheltered instruction
According to the Urban Institute, two-thirds of ELL students nationally come from low-income families.
Consequently, an ELL student who does poorly on state achievement tests can potentially affect a school's adequate yearly progress standing in as many as three categories: Limited English Proficiency, low income, and racial/ethnic.
Writing in the February 2006 issue of Principal Leadership, she reports on one elementary school where "chronically underachieving students made consistent and significant yearly gains on standardized tests when the SIOP model was implemented to a high degree by all teachers." Eighty-six percent of the third-graders who were enrolled in the school during the three years that SIOP was implemented scored at or above grade level on state assessments. Journal of Education for Students Placed At Risk, 10(4), 363-385. B., Merickel, A., Pérez, M., Linquanti, R., Socias, M., Spain, A., et al. Effects of the implementation of Proposition 227 on the education of English learners, K-12: Findings from a five-year evaluation. Educational attainment: Better than meets the eye, but large challenges remain [Fact sheet]. After 20 years of program evaluation research involving almost two dozen large and small school districts in urban, suburban, and rural settings in 15 states, Collier and Thomas (2004) write passionately about the "astounding effectiveness" of dual-language immersion.