In Business Insider, Chris Waller writes about some schools and districts that have changed their bell schedules so that teenagers start school later.

He notes:

To date, schools in 45 states have adopted a policy similar to Solebury’s. Each falls in line with the prevailing best practices proposed by organizations like the American Medical Association and the American Academy of Pediatrics.

The trend also reflects a change in attitude among administrators, who are now accepting the fact that obstacles like rejiggering athletics and transportation aren’t impossibilities. 

In the Summer 2012 issue of Education Next, Finley Edwards examined the impact of school start times on student achievement in “Do Schools Begin Too Early?”

He used data from Wake County, North Carolina, to study how start times affect the performance of middle school students on standardized tests. He wrote:

I find that delaying school start times by one hour, from roughly 7:30 to 8:30, increases standardized test scores by at least 2 percentile points in math and 1 percentile point in reading. The effect is largest for students with below-average test scores, suggesting that later start times would narrow gaps in student achievement.

— Education Next