Research from the University of Minnesota has helped to awaken a nationwide movement to start school later so students can get more sleep.
The most recent report, released last month, linked high school start times of 8:30 a.m. or later to a host of desirable results, including more sleep for students, better academic performance, reduced tardiness rates, and even reductions in teenagers' car crashes in the areas surrounding schools.
"I've been contacted by more than 300 school districts who want to have information about the start-time research," said Kyla Wahlstrom, the study's lead author and the director of the Center for Applied Research and Educational Improvement at the University of Minnesota in St. Paul. "There is interest across the nation about this."
This interest was further roused by U.S. Secretary of Education Arne Duncan's suggestion last fall that secondary schools start later so students can get more sleep.
"There's a lot of research and common sense that lots of teens struggle to get up ... to get on the bus," Duncan said during a radio show interview, in which he also stressed that he would not go so far as to dictate school start times. "I'd love to see more districts, you know, seriously contemplating a later start time."
The University of Minnesota researchers collected data from more than 9,000 students at eight public high schools in five districts in Colorado, Minnesota, and Wyoming. The schools served communities that were mainly white (60 percent to 90 percent) and middle to upper middle class (median family incomes of $54,000 to $95,173). However, Wahlstrom said that her previous research in the more racially diverse and higher-poverty Minneapolis district indicated that graduation rates increased and dropout rates declined after secondary schools there adopted later start times.
Within this more recent sample, the researchers found that grade point averages increased significantly in at least some core subjects in all but one of the five districts studied. High school tardiness decreased signifcantly in three of the four districts for which pre- and post-change data was available. The achievement-related findings are in line with those of a 2011 study, in which U.S. Air Force Academy freshmen experienced significantly higher levels of academic performance when they were randomly assigned to start school 50 minutes later than classmates in a control group. That study, by Scott E. Carrell of the University of California Davis, Teny Maghakian of Santa Clara University and James E. West of Baylor University, appeared in the peer-refereed American Economic Journal: Economic Policy.
The University of Minnesota study has not yet appeared in a peer-refereed journal. However, Elizabeth Miller, the chief of adolescent medicine at Children's Hospital of Pittsburgh, who was not involved in the research, has said, upon reviewing that study, that the methods are pragmatic and the findings promising.
In addition to collecting student achievement data from before and after school start times changed, the Minnesota researchers also surveyed students in all eight schools about their "daily activities, substance use, and sleep habits." However, Jackson Hole High School in Wyoming was the only place where researchers were able to collect this data both before and after the school start times changed. Jackson Hole also made the most dramatic change, increasing its start time by 80 minutes to 8:55 a.m. The 500 or so students at the school who filled out the surveys reported that their hours of weeknight sleep increased from 7.5 before the change to 8.2 hours afterwards. About two thirds of students got eight or more hours of sleep, as compared to 33 percent prior to the change.
According to, Wahlstrom, teens should get more than nine hours of sleep every night. But eight hours, she said, seems to be a tipping point where health-related benefits kick in. Consistent with past sleep studies, in all five districts, sleeping less than eight hours a night was correlated with higher levels of depression and caffeine intake.
A finding that Wahlstrom would like to investigate some more was that, in three of the four communities for which data was available, the number of school day car crashes involving teenagers declined after school start times changed. For this study, researchers were unable to discern which schools the teens attended but, given that the decreases were large (as much as 70 percent in Jackson Hole), Wahlstrom believes the finding merits further study.
Wahlstrom would also like to create a tool kit for school districts interested in adopting later start times for secondary students. That tool kit might include sleep research and practical responses to the sorts of objections that school board members might hear if they proposed such a change. These objections often raise questions about how later start times (and corresponding release times) would impact extracurriculars, student work schedules, and buses, which often deliver high school students first thing in the morning so elementary-age children do not have to wait in the dark. Wahlstrom said the coaches she interviewed noticed that students played better and were getting injured less when they got more sleep because school started later. Local employers generally wanted students at work closer to 4 p.m., by which time even the latest-starting schools are out. And buses? That can be more complicated, but Wahlstorm has found that it is possible to make changes without incurring additional costs.
"I was a school administrator," she said. "I know how buses can rule the world!"
Tellingly, to her knowledge, just one of the school district's she's worked with in the past 17 years has reversed its decision to start secondary schools later. And that, she said, was mainly because parents had protested that they had been given inadequate notice, just two months, to adjust their work schedules around the new start times.