Snooze or lose: High school start times and academic achievement

Many U.S. high schools start classes before 8:00 a.m., yet sleep science suggests that students' circadian rhythms shift to later in the day as they enter adolescence. Some school districts have moved to later start times for high schools based on the prospect that this would increase students' sleep and academic achievement. This paper examines the effect of high school start time on student learning using a nationally-representative sample of students. We also use time diaries to examine the effects of start time on students' time allocation in order to explore the mechanisms through which changing start time affects learning. Results indicate that female students who attend schools with later start times get more sleep and score higher on reading tests. Male students get more nighttime sleep when schools start later, but their daily sleep is unchanged due to a decrease in napping; their test scores do not change.