A's from Zzzz's? The Causal Effect of School Start Time on the Academic Achievement of Adolescents

Abstract

Recent sleep research finds that many adolescents are sleep-deprived because of both early school start times and changing sleep patterns during the teen years. This study identifies the causal effect of school start time on academic achievement by using two policy changes in the daily schedule at the US Air Force Academy along with the randomized placement of freshman students to courses and instructors. Results show that starting the school day 50 minutes later has a significant positive effect on student achievement, which is roughly equivalent to raising teacher quality by one standard deviation. (JEL I23, J13)

Advancing a Biopsychosocial and Contextual Model of Sleep in Adolescence: A Review and Introduction to the Special Issue

“…In fact, while this article and Special Issue were being prepared, the American Academy of Pediatrics released a policy statement recommending that middle and high schools delay the start of class to 8:30 a.m. or later (American Academy of Pediatrics 2014). A sizeable body of research finds earlier school start times to be associated with adolescents obtaining less sleep, exhibiting increased daytime sleepiness, and being more frequently tardy to school (Carrell et al 2011;Carskadon et al 1998;Dexter et al 2003;Edwards 2012;Hansen et al 2005;Owens et al 2010;Wahlstrom et al 2014;Wolfson et al 2007;Zhou et al 2012). Lufi et al (2011) showed that middle school students showed improved attention and decreased impulsivity when school start time was delayed by 1 h. Owens et al (2010) also found that adolescents showed improved mood and greater motivation after a later school start time was implemented.…”

“…In particular, studies to date have primarily compared youth in schools with different start times or compared youth's functioning before and after a change in school start time. While clearly instrumental, the lack of experimental research in this area makes it difficult to establish definitive causal claims (however, see Carrell et al 2011, for a compelling example supporting a causal link). Furthermore, studies have yet to consider potentially important moderators, such as pubertal status, chronotype, participation in extracurricular activities, and socioeconomics.…”

The educational effects of school start times

“…A study analyzing course grade data for first-year students at the US Air Force Academy found similar results [11]. Several characteristics of the academic setting there allow for a compelling study of the effects of start time.…”

“…However, certain students benefit more than others. Both the North Carolina and Air Force Academy studies find that the benefits of later start times are largest for students at the bottom of the grade distribution [1], [11]. Figure 2 shows how the effect of a one-hour delay in start times differs across the grade distribution at middle schools in Wake County, North Carolina.…”

“…The randomized scheduling at the US Air Force Academy provides the best opportunity to shed some light on this problem. The Air Force Academy study assessed how student performance differs across class periods relative to first period, holding all else constant [11]. As shown in Figure 3 …”