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Want To Improve Test Scores? Start the School Day Later and Take Away Student Devices at Night

When the school day starts later and students leave technology outside their bedrooms at night, grades and student health both improve due to increased sleep, according to a new report from researchers at the University of Minnesota.

The report, "Examining the Impact of Later High School Start Times on the Health and Academic Performance of High School Students: A Multi-Site Study," is the result of a three-year project looking at data from 9,000 students at eight high schools in three states.

Key findings of the study include:

  • Academic performance and standardized test scores improved in English, math, science and social studies at schools that switched to a later start time;
  • Tardiness and absenteeism decreased when start times were delayed;
  • Depression symptoms, substance abuse and caffeine consumption declined at schools with later starts; and
  • At Wyoming's Jackson Hole High School, the school that moved to the latest start time at 8:55, motor vehicle crashes involving teenage drivers dropped by 70 percent.

Researchers also found that students who reported having technology in their bedrooms were less likely to sleep at least eight hours per night due to blue light from the devices or being disturbed by incoming texts, phone calls or emails.

"Having either a computer or a phone in the bedroom was significantly related to amount of sleep," according to the report, "where students with either a phone or computer in their bedrooms were more likely to obtain less than 8 hours of sleep than students without these items in their bedrooms."

"The research confirmed what has been suspected for some time," said Kyla Wahlstrom, director of the U of M's Center for Applied Research and Educational Improvement (CAREI), which conducted the study, in a prepared statement. "High schools across the country that have later start times show significant improvements in many areas. The reduction of teen car crashes may be the most important finding of all, as the well-being of teens and the safety of the general public are interrelated."

"Even a start time of 8:35 a.m. allows 57-60 percent of students to get eight or more hours of sleep, which is an important health benefit for a majority of students," added Wahlstrom. "Local school districts, school personnel, parents, and students need to understand the importance of sleep and to make choices using the knowledge from this and other studies."

At the school with the latest start time in the study, 8:55, 66 percent of students reported getting at least eight hours of sleep per night. At the other end, students who started their day at the earliest time, 7:30, only reported getting at least eight hours of sleep at a rate of 33.6 percent.

When asked for the ideal time to start school, three-quarters of students surveyed said 8:30 or later and half said it was no earlier than 9:00.

The report points to earlier research that suggests student preferences for later start times may, in fact, be rooted in biology, rather than a simple desire to stay up late at night.

"Although there might be social and environmental factors that influence adolescents' sleep behavior, recent research on the sleep-wake cycle of teens has identified changes in specific biological processes that occur with the onset of puberty that cause adolescents not only to need more sleep but also to feel sleepy at a later time. Because the sleep-wake cycle changes as children grow into adolescents, early high school start time has been identified as an important external factor that could restrict sleep and negatively affect academic learning," wrote the authors, citing studies from 2007 and 2010.

In their conclusion, the researchers noted that "a strong resistance to a delayed high school start time exists in many localities across the" country. "However," they added, "given the analyses summarized here, there are clear benefits for students whose high schools start at 8:30 AM or later. This would include, for teens who reported they got at least eight hours of sleep per night, that they were more likely to say they have good overall health and were less likely to report being depressed or using caffeine and other substances (e.g., alcohol, tobacco, other drugs). Other positive findings include a significant reduction in local car crashes, less absenteeism, less tardiness, as well as higher test scores on national achievement tests."

The study was funded by the Centers for Disease Control and Prevention and included data obtained at Boulder High School, East Ridge High School, Fairview High School, Jackson Hole High School, Mahtomedi High School, Park High School, St. Louis Park High School and Woodbury High School.

To access the full report, visit

About the Author

Joshua Bolkan is contributing editor for Campus Technology, THE Journal and STEAM Universe. He can be reached at [email protected].