States and districts are starting to flag schools where subgroups of students are underperforming under the Every Student Succeeds Act. But advocates are concerned that they might miss some schools that need serious help because of the way their ESSA plans are designed.

So is that happening? It appears to be. But, so far, it’s in a very small subset of states, an analysis by the Alliance for Excellent Education, a research and advocacy organization that works to ensure students graduate from high school prepared for college and the workforce.

According to the Alliance, Arkansas and Connecticut might be missing some schools where subgroups of students—English-language learners, students in special education, racial minorities, and disadvantaged students—are performing as poorly as the students in the worst schools in the state. And it’s unclear if Michigan, Virginia, and Wisconsin are in the same boat.

Here’s why: ESSA requires states to flag schools for “comprehensive support and intervention” (the bottom 5 percent of schools in the state, plus where fewer than two-thirds of students graduate) and “additional targeted support and intervention” (those where at least one subgroup of vulnerable students is struggling as much as the bottom 5 percent). States also must flag another category of schools where subgroups aren’t performing well for “targeted support and intervention,” but they have much more leeway on how to define what that means.

Some states decided to pick their “additional targeted support” schools, from among their “targeted support schools.” That’s kosher under ESSA. The problem: In at least a couple states, the definition of “targeted support” means fewer schools will be flagged because the state’s definition of “targeted support” is narrower than the definition of “additional targeted support.”

That’s problematic, because students in those schools will miss out on extra help from the state and district, write Lindsay Dworkin is director of policy development and state government relations and Anne Hyslop is assistant director of policy development and government relations in a blog post.

“A central value underlying ESSA is that every student should have the opportunity to succeed,” they write. “A key way the law advances that goal is requiring improvement efforts in schools when even one subgroup of students is struggling, even if the overall student population does not.”