It's the first day of school at Hall Fletcher Elementary in Asheville, N.C. Principal Gordon Grant stands outside in a white suit and bow tie, greeting students. The kids arrive sporting fresh haircuts and new shoes. One even wears a tutu.

But the biggest change on this first day of school may be the least obvious. It's July, and students are returning after just five weeks of break. This public school is beginning a three-year experiment, running on a year-round schedule for the first time. The students will get the same number of school days as others in the district, just distributed differently: five weeks in the summer, three-week breaks in September and March, plus a winter holiday vacation.

A primary motivation for the change is to make sure kids don't fall behind academically over the long summer break — a phenomenon known as the "summer slide." About 80 percent of the students at this school are eligible for free and reduced lunch, and Grant says, "children who don't have really good enriching opportunities provided for them in the summer move back academically."

Tamera Owen is the grandmother of two students at Hall Fletcher, a kindergartner and a second-grader, and she says she can see them "retaining things that they learned."

Karl Alexander is a sociology professor at Johns Hopkins University. He studies learning gaps between students at different income levels. He says a gap widens during the summer break, when "school is out of the picture" and students are dependent on the resources of their families and communities. Asheville City Schools has seen this pattern first-hand, after giving students tests before and after summer vacation.

According to a recent report from the Congressional Research Service, 3,700 public schools in the United States operate year-round. That's about 4 percent of the nation's schools. They are most common in the South. While research on student achievement in year-round schools is spotty and inconclusive, some studies have shown a small, positive effect.

Paul von Hippel studies educational inequality at the University of Texas at Austin, and he says the benefits of year-round school seem to even out over time: "Students learn more in the summer," but, on the other hand, "they're learning less in the school year."

This isn't the first time Hall Fletcher has tried to shift to a year-round schedule, also known as a "balanced schedule." They experimented with the idea back in the '90s.

"After three years they dropped it because of the mismatch of the balanced school year calendar with the regular school year calendar," says Principal Grant. "I think we've done a better job of matching those calendars this year."

This story comes to us from member station WCQS in Asheville, N.C.

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