For years, schools have often grouped English learners (ELs) together in classrooms to provide targeted language instruction and manage limited resources. However, new research questions the effectiveness of this approach.
A recent study published in the Peabody Journal of Education examined outcomes for high school ELs who were placed together in core academic courses. The researchers found that students in these concentrated EL groups had lower rates of graduation and college enrollment compared to those in more mixed classroom settings.
“Many well-intentioned educators are trying to manage logistical complexities of staffing and scheduling,” said Kristin Black, lead author of the study and research scientist at the Institute for Human Development and Social Change at NYU Steinhardt. “We need to learn more about whether there are particular English learners who might be able to benefit from this kind of segregated course environment, but our latest study suggests that school leaders should be much more cautious about this practice.”
The findings add to existing research challenging the practice of grouping ELs together. Another study published in the October 2025 issue of American Education Research Journal tested the effects of teaching elementary school ELs in homogenous versus heterogenous groups. It found no significant differences in academic outcomes for most students.
“Across these two studies and others, our findings challenge the default practice of separating English learners for instruction. While the details depend on student and school characteristics, we found little evidence that grouping English learners separately yields academic benefits for most students,” said NYU Steinhardt Professor Michael Kieffer, lead author of the AERJ study and co-author of the PJE study. “Furthermore, we found troubling evidence that it can have meaningful negative associations with later outcomes.”
In their analysis, Black and her colleagues used data from New York City Public Schools covering 31,303 ELs who started ninth grade between 2013 and 2015. Students were categorized by how long they had been learning English before ninth grade: newcomer (1-3 years), developing (4-6 years), or long-term (7 or more years). High schools were classified based on whether their EL population was above or below 50%. The team then measured how concentrations of EL students affected graduation rates after four and six years as well as college enrollment immediately after graduation or within two-and-a-half years.
The results showed that higher concentrations of EL students in courses were linked with a reduced likelihood of graduating high school or enrolling in college—regardless of prior English learning experience or overall percentage of ELs at a given school. Specifically, students in high-concentration EL courses were 10-15% less likely to graduate within four years, 6-11% less likely within six years, 12-13% less likely to enroll in college immediately after graduation, and 9-13% less likely to enroll within two-and-a-half years.
In an elementary school context, Kieffer’s team randomly assigned fourth- and fifth-grade ELs into either all-EL groups or mixed groups with non-EL peers. Both received identical language instruction over twelve weeks from the same teachers. The researchers assessed performance across language skills, reading comprehension, and argumentative writing while also observing instructional practices.
Overall results did not show statistically significant differences between group types for average student achievement. Heterogeneous groups provided some advantages for students with stronger English skills; homogeneous groups benefited those with lower proficiency levels.
“When we observed heterogeneous groups, we saw teachers using more open-ended questions and promoting richer discourse, suggesting the benefits of these groups for most students,” said Kieffer. “At the same time, the subset of students at earlier levels in their English learning did benefit from being grouped homogeneously. This may be because teachers provided more targeted language instruction appropriate to their particular levels when teaching homogeneous groups. Nonetheless, these results suggest grouping English learners together should be done sparingly and strategically.”
“English learners have a right to be integrated into the life of their school, and an important part of that experience is taking courses with English-proficient peers,” said Black. “These findings should push us to rethink what is often a default practice of scheduling English learners into separate classrooms.”
Both studies received funding from the Institute of Education Sciences at the US Department of Education.
