High school students get more sleep, come to school more regularly, and change schools less often when they can start school later, suggests a study of Minneapolis public schools.
The study, presented to that city’s school board on Aug. 28, is described as the first to take a long-term look at the impact of changes in high school starting times.
Researchers studying adolescent sleep patterns have long noted that the typical near-dawn starting times of most high schools are out of sync with teenagers’ natural sleep rhythms. The result, studies show, is that teenagers on average get less than the 8 1/2 to 9 1/4 hours of sleep they need to stay alert in class or to keep from nodding off behind the wheel of a car. (“In Some Districts, the Bell Tolls Later for Teens,” March 11, 1998.)
An executive summary of the school start time study is available from the Center for Applied Research and Education Improvement.
Minneapolis school officials were mindful of that research in 1997, when they moved the starting times for their seven high schools from 7:15 a.m. to 8:40 a.m. Since then, dozens of other districts, from Gwinnett County, Ga., to Bellevue, Wash., have followed suit in an effort to allow students to get more sleep. But no major study until now has looked at whether the changes in starting times make a difference in students’ sleep habits, grades, and attendance rates.
For their study, researchers from the University of Minnesota’s Center for Applied Research and Educational Improvement drew on grades and attendance records in Minneapolis from three years before the schedule changes were made until two years after. They also surveyed random samples of 9th through 12th graders on their sleep habits.
The research team is also taking a similar look at the impact of later high school starting times in Edina, Minn., a more affluent Minneapolis suburb that revised its high school schedules a year earlier. Results from that study are not yet complete.
Getting More Sleep
One of the crucial findings of the Minneapolis study, researchers said, is that students got an average of five hours more sleep each week after the change in schedules. Critics often contend that moving high school starting times is useless because teenagers will just go to bed later at night if they know they can sleep later the next day.
“That worry has not been borne out at all,” said Kyla J. Wahlstrom, the lead researcher for the project and the associate director of the University of Minnesota center. “Once teenagers get sleepy at about 11 p.m., they get sleepy. They’re going to bed.”
While attendance rates improved across the board for 9th, 10th, and 11th graders, the greatest gains came among those students who had been the most transient before. Those were the students, in other words, who had not been in the same school—or feeder school—in the two years prior to the study.
What’s more, the study found, the percentage of students who fell into that category shrank in the years following the starting-time changes. The percentage of 10th graders who had been continuously enrolled, for example, grew from 55 percent in the 1995-96 school year to 67 percent in 1999-2000.
Minneapolis school leaders said the improvement was particularly important for their 49,000-student district, where shortages of affordable housing contribute to high student-mobility rates. Districtwide, 44 percent of students change schools each year.
“The fact that the start time seems to have had a stabilizing influence on that is something that’s very helpful to us,” said Judy L. Farmer, a longtime school board member. “And changing start times did not cost us more money.”
One reason the later starting time might help reduce mobility, Ms. Wahlstrom speculated, is that some high school students believe it looks better on their records to change schools when the number of absences they accumulate puts them at risk of failing a course, or to drop out and re-enroll later. With more time to make it to school in the morning, they are less likely to rack up so many absences in the first place.
The schedule changes did not significantly affect students’ grades, however. Ms. Wahlstrom said the reason may have to do with the fact that more struggling students are staying in school. “When you’ve got more kids staying in school, you’re going to have greater variability in the overall grades earned,” she said.
But Richard S. Schwartz, a longtime teacher at the district’s Southwest High School, said his own experiences suggest that most students at least appear to be doing better.
“Kids are absolutely coming in more ready, more prepared to learn, and sharper,” Mr. Schwartz said. “Beginning to teach in pitch dark made for kind of a dreary situation.”