Still, given the wide socioeconomic gaps and educational disparities across the United States, many schools, charter networks, and districts have turned to extended learning time as a pragmatic reform. States like Massachusetts have spearheaded pilot programs for longer school days and have seen strong results. In 2013, D.C. Public Schools implemented extended hours for eight of its struggling schools and saw some of its largest gains in math and reading since 2008.

Although many disadvantaged schools are considering a longer day, there are a lot of unanswered questions: How does this affect students? How can districts cover the increased costs? And perhaps most importantly, does this extra time in the classroom actually make low-income students more competitive with their peers?

The teachers I spoke with said extended school days can work, but only if the extra time is used effectively. If the hours at school seem wasted, students, families, and teachers don’t get invested—their buy-in is crucial.

Peter Smith* directs a Philadelphia high school that extends its day—but only by a half an hour for students. Hours run from 8:00 a.m. to 3:17 p.m. After school, teachers are required to stay for office hours from 3:17 p.m. to 4:00 p.m. While teachers are in school for an hour and 15 minutes longer than other teachers in the district, they actually teach less than they would in a traditional public school.

“Teachers are totally on board,” Smith says. “Teachers love having that designated time [after school] to be with students, and it does free up their time during the other parts of the school day, and parents love it—especially at the high school level.”

Extended school days can also provide structured planning time for teachers. Without this built-in time, teachers end up working additional hours after school and on the weekends, clocking in as much time as they would if the day were extended—if not more.

Andrew Davis* was a teacher at a charter school in Memphis that extended its day. In his original teaching schedule, he was given two hours a day to plan and collaborate with other teachers. “[It] was great,” he says, “but since I taught two grade levels, it was definitely needed anyways.”

His school originally had an academic day that lasted from 7:30 a.m. to 5:00 p.m., and students would stay late if they had extracurricular activities. Davis would arrive early and stay late to coach cross-country, typically clocking in a 13- or 14-hour day.

“It was exhausting,” he says of those first two years. But, the school was “able to offer longer class periods, build in restroom breaks and student celebrations, and provide teachers with time for meetings and planning time inside the school day so that we had less out-of-school-time meetings.”

Despite being able to provide extra time for teacher planning and class periods, the 10-and-a-half-hour day wore on both teachers and students, creating teacher burnout and student behavior issues. Since then, the school day has been shortened and now ends at 4:00 p.m. “When we shifted to the shorter school day, along with other changes, we saw much more positive student response to the school and a greater school culture with less behavior issues in the school,” he says.