Evidence that supports later start times for teens 

This report from the University of Minnesota presents findings from a three-year study on high school start times. It examined whether or not a delay in start times had an impact on students' overall health and academic performance.

The study consisted of three parts. Part 1 involved collecting survey data from over 9,000 students across eight high schools in five school districts. Students were individually surveyed about their daily activities, substance use, and sleep habits. In Part 2 of the study, researchers collected data regarding students' academic performance, such as grades earned, attendance, tardiness, and performance on state and national tests. The researchers also examined car crash data for the communities involved in the project. Part 3 of the study included an examination of the processes by which local school districts made the decision to change to a later start time. 

Key findings included:

• High schools that start at 8:30 AM or later allow for more than 60% of students to obtain at least eight hours of sleep per school night;
• Teens getting less than eight hours of sleep reported significantly higher depression symptoms, greater use of caffeine, and are at greater risk for making poor choices for substance use;
• Academic performance outcomes, including grades earned in core subject areas of math, English, science, and social studies, plus performance on state and national achievement tests, attendance rates, and reduced tardiness, show significantly positive improvement with the start times of8:35 AM or later; and
• The number of car crashes for teen drivers from 16 to 18 years of age was significantly reduced (by 70%) when a school shifted start times from 7:35 AM to 8:55 AM.   

Johns Hopkins University 

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