More hours in the school day for teachers as well as students can lead to improved academic achievement, according to a new report that studies 17 schools across the nation that give teachers more time for collaboration and professional development.

The average American teacher spends less than 20 percent of school time outside the classroom – about seven hours per week – according to “Rethinking Teacher Time,” a report released Wednesday by the National Center on Time and Learning, a nonprofit group based in Boston that promotes expanding the regular school day.

Time for collaboration and professional development is more important than ever with the introduction of the Common Core state standards because teachers are “on the frontiers of both unpacking and applying the new standards,” according to the researchers. “Teachers are becoming the experts, and they can both learn from and with one another,” the researchers said. The report emphasizes that the extra time must be focused on school goals and involve peer-to-peer learning.

The schools in the study were chosen because they allowed teachers twice the average amount of school time outside the classroom, their students’ academic achievement was higher than neighboring schools, at least half of their students were from low-income families, and they had “demonstrated significant growth in student performance outcomes since they began an expanded learning schedule.”

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