Ask any parent who has tried to rouse a slumbering teenager in order to get to school on time—in other words, any parent of a teenager—and they’ll tell you that teenagers today do not get enough sleep. Research bears this out: 90 percent of parents say that their children are not getting enough sleep, and 60 percent of teenagers report extreme daytime sleepiness.
This problem is due in part to early school start times—some as early as 7 a.m. Teenagers are hardwired to stay up later than their younger siblings and to sleep later, too. But the typical middle school and high school start at 8 a.m. As a consequence, teenagers on average get only around 7 hours to 7.5 hours of sleep per night, about two hours less than what researchers recommend. To the authors’ knowledge, no one has calculated the national student achievement gains that delaying the start times of the nation’s schools would yield. This analysis is an attempt to do just that.
The authors relied on work by researcher Finley Edwards, who showed that if a middle school in Wake County, North Carolina, pushed its start time back an hour, the school would see a 2 percentile growth in math scores.
The authors used Edwards’ methodology to determine what a similar policy change might mean on a national scale. The authors looked at potential gains on the 2015 National Assessment of Educational Progress, or NAEP, if all public middle schools delayed their start times an hour.
More specifically, the authors estimated the effect size—or the increase in average scale scores—of a one-hour later school start time on scores for the 2015 NAEP math and reading exams. To determine this effect size, the authors multiplied the standard deviation for each NAEP exam by the change in its z-score, a statistical term used to describe distance from the mean. The authors used the change in z-scores that Finley Edwards found in his analysis: 0.07 and 0.05 for math and reading, respectively. The resulting figure yielded the effect size.
The authors found that national NAEP math scale scores for eighth-grade students would go up as much as 8 points if every school had a one-hour later start time. According to many education experts, this gain is equivalent to almost a full grade-level increase, which is typically cited as 10 points. High schools would likely show very similar gains, although the authors did not include high schools in their study.
It is important to note that this analysis includes a number of assumptions. For instance, the authors assumed that gains in Wake County would replicate across the nation. However, middle-school students in Wake County start school much earlier than most schools nationwide, and many of the gains found in the Edwards analysis were derived from schools that had start times as early as 7:30 a.m.
In addition, the authors assumed that outcomes for North Carolina’s state standardized assessments would be replicated on NAEP, a nationally representative exam. However, researchers agree that NAEP and state assessments “may differ in scope and content” and that NAEP exams tend to be more rigorous. Nonetheless, the authors’ findings still give a concrete sense of the benefits of updating school opening policies.
Schools and sleep
Whatever the specific case, what is clear is that there is a growing body of evidence suggesting that a good night’s rest helps students learn. According to many researchers, sleep increases a student’s ability to focus and process information, and the effects of more sleep on student outcomes is often very significant. In fact, research studies recommend that teenagers sleep around 9 hours each night in order to perform their best.
Students with longer sleep times report significantly higher grades than students with poor sleeping schedules, according to one recent paper. Another new study found that sleep can reduce the amount of time needed to learn by more than 50 percent. The study found that participants who slept between each learning session in the study were able to retain the information at a quicker pace than participants who did not sleep between sessions. Still another article argues that there is a clear “association between sleep and GPA” among college students.
According to researchers, sleep provides a number of benefits. First, it improves focus, and students who are more rested can concentrate better. Second, sleep helps with memory, and shut-eye also appears to help reinforce memories. These benefits all work to help a student’s ability to learn.
But still, many schools force students—and their families—to wake up very early in the morning. As part of their analysis, the authors found that the median school day—for elementary, middle, and high school—starts at 8:05 a.m. and ends at 2:50 p.m. Many schedules, however, are particularly egregious when it comes to start times. Some high schools in Hillsborough County, for example, open at 7:30 a.m. In Howard County, Maryland, high schools start at 7:25 a.m.
Many schools have established these schedules in order to accommodate various transportation issues. More specifically, many school administrators arrange start times according to their districts’ busing schedules, or the times that school buses arrive to drop off students. Since school buses tend to run multiple routes in the morning, this forces some students to arrive at school and start class earlier than others. Other reasons for early start times include concerns about afterschool programs: If a school starts late, then the school day ends late, and that means that afterschool programs can end late in the evening.
However, these early opening and dismissal times place a heavy burden on parents, particularly parents with traditional work schedules who must wake up several hours earlier than usual in order to get their children to school on time and leave work several hours early to pick them up. These school schedules also do not match up with the established science that suggests that teenagers often stay up late due to hormonal changes—such as melatonin increases that occur in the brain during one’s teenage years—and so while teenagers need nine hours of sleep per night, they typically get only around seven hours and have a harder time waking up.
Over the past decade, many schools across the country have shifted their start times to provide better hours of learning for students and their families. In Jessamine County, Kentucky, for instance, the superintendent moved all start times for elementary, middle, and high schools to after 8 a.m.
Similarly, Seattle recently adopted a plan to start most of its middle and high schools at 8:45 a.m. and most of its elementary schools at 9:35 a.m. Other schools, such as Joaquin Moraga Intermediate School in California, are paying close attention to the sleep and health benefits of later school times and changing their bell schedules accordingly.
These schools provide some hope, and in the end, better school schedules not only help parents but also support student success. In order to improve achievement outcomes for students, as well as the lives of working families, school leaders should rethink how early students start the school day.
Ulrich Boser is a Senior Fellow at the Center for American Progress. Catherine Brown is the Vice President of Education Policy. Perpetual Baffour is a Research Assistant for the K-12 Education Policy team at the Center. The authors would like to thank Finley Edwards, who reviewed an early version of the column.
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