Gaps in test scores narrow when students who have not mastered English are not isolated in low-achieving schools, according to a new report from the Pew Center for English-Language learning.

The report released June 26 noted that students designated as English language learners (ELL) tend to go to public schools with low standardized test scores – schools where other groups are also struggling. These schools generally have high student-teacher ratios, high student enrollments and high student poverty rates, the report said.

The report focused on public schools in Arizona, California, Florida, New York and Texas, states that educated about 70 percent of the nation’s students enrolled in English language learning (ELL) programs.

As defined in the report, “English language learner (ELL) students are designated by public schools as students who cannot excel in an English language classroom. Designation procedures vary across states and school districts but often include a test of the student’s English reading and writing skills as well as listening and speaking abilities.”

“The continued growth of the ELL student population will present large challenges for some public schools and school districts in meeting requirements of the No Child Left Behind Act,” the report said. “NCLB mandates that all groups of students, including ELLs, meet state proficiency standards in mathematics and reading by 2014. Recent results from national and state assessments indicate that ELL students are among the groups least likely to meet state proficiency standards. One of the fastest-growing groups of students is also one of the lowest-achieving student groups in both mathematics and reading.”

Previous studies have found that ELL students are much less likely than other students to score at or above proficient levels in both mathematics and reading/language arts.

Pew Hispanic center said this report builds on previous studies “by illustrating that the educational isolation of ELL students is associated with the math proficiency gap between English language learners and other students.”