The Impact of School Start Times on Adolescent Health and Academic Performance

“The present study adds to the field by demonstrating that middle school students are also at an advantage when school start times are delayed. [¶] In addition to the sleep deficit, school records indicated that students at the earlier starting school [7:15 a.m.] were tardy four times more frequently, and eighth graders at the earlier starting school obtained significantly worse average grades than the eighth graders at the comparison, later starting school. [8:37 a.m.]. [¶] Students at later starting middle and high schools obtain more sleep due to later wake times and, in turn, function more effectively in school.” (Wolfson, Spaulding, Dandrow, & Baroni, Middle School Start Times: The Importance of a Good Night’s Sleep for Young Adolescents (Aug. 15, 2007) 5 Behavioral Sleep Med. 3, pp. 204, 205; see also, Hagenauer, Perryman, Lee, & Carskadon, Adolescent Changes in the Homeostatic and Circadian Regulation of Sleep (2009) 31 Developmental Neuroscience 4, p. 282; Wolfson, Adolescent Sleep Update: Narrowing the Gap between Research and Practice (Mar./Apr. 2007) Sleep Rev.: J. Sleep Specialists.)

A recent longitudinal study “demonstrated that adolescent changes in sleep (delayed sleep phase and disrupted sleep) are evident prior to the bodily changes associated with puberty.” (Wolfson & Richards, Young Adolescents: Struggles with Insufficient Sleep, publish. in, Sleep and Development (Oxford Univ. Press, El Sheikh edit. 2011) p. 268, citing, Sadeh, Dahl, Shahar, & Rosenblat-Stein, Sleep and the Transition to Adolescence: A Longitudinal Study (2009) 32 Sleep 12, pp. 1602-1609.) Middle school populations may be substantially composed of post-pubescent children. The normal age range of pubertal onset (Tanner stage 2) is between 8 and 13 years in girls and between 9 years 6 months and 13 years, 6 months in boys. (Carel & Léger, Precocious Puberty (2008) 358 N. England J. Medicine 22, p. 2366; see also, Stang & Story, Adolescent Growth and Development, publish. in, Guidelines for Adolescent Nutrition Services (Stang & Story, edits., Univ. Minn. 2005) p. 1.)

Carskadon‘s 1993 study found that “pubertal maturation at this transitional phase (age 11/12 years) has a significant influence on phase preference and that psychosocial factors are less significant than anticipated.” (Carskadon, Vieira, & Acebo, Association between puberty and delayed phase preference (1993) 16 Sleep 3, p. 261.) “As early as middle school, adolescents … report significantly delayed bedtimes and wake times, particularly on weekends.” (Wolfson & Richards, Young Adolescents: Struggles with Insufficient Sleep, publish. in, Sleep and Development, supra, p. 268, citations omitted.) The magnitude of the delay increases as children progress through adolescence. (See, e.g., Kelley, Lockley, Foster, & Kelley, Synchronizing education to adolescent biology: ‘let teens sleep, start school later’ (Aug. 1, 2014) Learning, Media and Technology, pp. 8-9; Millman, edit., Excessive Sleepiness in Adolescents and Young Adults: Causes, Consequences, and Treatment Strategies (Jun. 2005) 115 Pediatrics 6, pp. 1774-1786.)

In 1997, the National Institutes of Health identified adolescents and emerging adults (ages 12-25) as populations at “high risk” for problem sleepiness, pointing to early school scheduling a specific factor contributing to restricted sleep and its associated difficulties. (Working Group on Problem Sleepiness (Aug. 1997) Nat. Center on Sleep Disorders Research, Nat. Inst. Health, pp. 6, 7; Problem Sleepiness (Sept. 1997) Nat. Inst. Health, No. 97-4071, p. 2; see also, Educating Youth About Sleep and Drowsy Driving (Sept. 1998) Nat. Inst. Health, p. 10.)

Since at least 2004, sleep scientists have specifically identified middle school students as benefiting from later school schedules. Researchers studying a cohort of 2,259 students, aged 11 to 14 years, found that students who obtained less sleep in sixth grade exhibited lower initial self-esteem and grades and higher initial levels of depressive symptoms. Similarly, students who obtained less sleep over time reported heightened levels of depressive symptoms and decreased self-esteem. The scientists concluded, “Where possible, efforts should be made to encourage lighter homework loads and later school start times, so that adolescents can go to bed and wake up at times that are more suited to their bodily rhythms.” (Fredriksen, Rhodes, Reddy, & Way, Sleepless in Chicago: Tracking the Effects of Adolescent Sleep Loss During the Middle School Years (Jan./Feb. 2004) 75 Child Development 1, p. 94.)

“The often serious impact of this chronic under-sleeping is now evident in both high school and middle school students. [¶] For all students one of the most salient—and correctable—social factors contributing to student sleep deprivation, is school start times. [¶] … These two biological factors underlie the main difficulties faced by adolescents attending school before 9:00 a.m.: the general problem that one cannot easily fall asleep before their biological bedtime, and the additional problem that puberty creates a tendency for even later bedtimes. [¶] Though research has not yet identified an ideal school schedule, the wealth of evidence reviewed in this chapter and elsewhere strongly suggests that students have a better opportunity to be rested and ready to learn by delaying school start time to 8:30 a.m. or later.” (O’Malley and O’Malley, School Start Time and Its Impact on Learning and Behavior, publish. in, Sleep and Psychiatric Disorders in Children and Adolescents (Ivanenko edit., Informa Healthcare 2008) pp. 79, 84, 89.)

A 2008 Chattanooga Crime Task Force Committee chaired by University of Tennessee Associate Professor of Criminal Justice Roger Thompson, Ed.D., proposed adopting an 8:30 a.m. start time for all Hamilton County middle and high schools as part of a comprehensive plan to address secondary school truancy. (Chattanooga Crime Task Force Comm. (2008) Crime Task Force Rep., p. 15, Recommendation No. 7.)

A study of Israeli middle school children published in April 2011 “strongly recommends that middle schools should consider delaying the school starting time by at least one hour. Such a change could enhance students’ cognitive performance by improving their attention level, increasing rate of performance, as well as reducing their mistakes and impulsivity.” The study delayed start times from 7:30 a.m. to 8:30 a.m. The children’s sleep was 55 minutes longer each night. (Lufi, Tzischinsky, & Hadar, Delaying School Starting Time by One Hour: Some Effects on Attention Levels in Adolescents (Apr. 2011) 7 J. Clinical Sleep Med. 2, pp. 137-143.)

Finley Edwards’ seven-year study of middle school students in Wake County, North Carolina, now the 16th largest school district in the country, found delaying start times by one hour (i.e., to 8:30 a.m.) led to gains of 1.5 to 3 percentile points in standardized math test scores (0.06 to 0.09 standard deviations) and reading test scores (0.03 to 0.10 standard deviations). (Edwards, Early to Rise? The Effect of Daily Start Times on Academic Performance (Dec. 2012) 31 Economics of Education Rev. 6, pp. 970-983; Edwards, Do Schools Begin Too Early? (Summer 2012) 12 Education Next 3.) With most middle schools beginning at 8:15 a.m. (Edwards, Do Schools Begin Too Early?, supra, 12 Education Next 3), the gains in Edwards‘ data derive largely from the changes from 7:30 a.m. to 8:15 a.m. (Edwards, Early to Rise? The Effect of Daily Start Times on Academic Performance, supra, 31 Economics of Education Rev. 6, p. 971.) Students at the lower end of the distribution (i.e., disadvantaged students) benefited the most, with effects roughly twice as large as advantaged students, potentially relevant for schools attempting to meet minimum competency requirements. (Edwards, Early to Rise? The Effect of Daily Start Times on Academic Performance, supra, 31 Economics of Education Rev. 6, pp. 970, 971, 978, 983; Edwards, Do Schools Begin Too Early?, supra, 12 Education Next 3.) In addition, the benefits of later start times increased as the children progressed through adolescence. (Edwards, Early to Rise? The Effect of Daily Start Times on Academic Performance, supra, 31 Economics of Education Rev. 6, pp. 971, 982; Edwards, Do Schools Begin Too Early?, supra, 12 Education Next 3.)

Moreover, tests administered to high school sophomores showed “[t]he benefits of a later start time in middle school appear to persist through at least the 10th grade.” (Edwards, Do Schools Begin Too Early?, supra, 12 Education Next 3.) By contrast, “the negative impact of early start times persists over time.” (Edwards, Early to Rise? The Effect of Daily Start Times on Academic Performance, supra, 31 Economics of Education Rev. 6, p. 981.) Edwards also found later start times associated with decreased absences, less time spent watching television and a greater amount of time spent on homework, indicating that these factors may help explain why later starting students have higher test scores. (Edwards, Early to Rise? The Effect of Daily Start Times on Academic Performance, supra, 31 Economics of Education Rev. 6, pp. 971, 982; Edwards, Do Schools Begin Too Early?, supra, 12 Education Next 3.) In sum, Edwards finds that “an increase in start times by 1 h would lead to a 3 percentile point gain in both math and reading test scores for the average student.” (Edwards, Early to Rise? The Effect of Daily Start Times on Academic Performance, supra, 31 Economics of Education Rev. 6, p. 982; Buckhalt, Can Later Start Times Affect School Achievement? (Sept. 30, 2012) Psychology Today [citing Edwards‘ study as “direct evidence” of the “measurable significant effect” of later start times on adolescent academic achievement].)

As noted elsewhere (see, §§ III.A.; IV; and, Appendix C, supra, Start Time Recommendations, etc.), Brookings Institute economists “conservatively” estimate that shifting middle and high school start times, “from roughly 8 a.m. to 9 a.m.[,]” will increase academic achievement by 0.175 standard deviations on average, with effects for disadvantaged students roughly twice as large as advantaged students. (Jacob & Rockoff, Organizing Schools to Improve Student Achievement: Start Times, Grade Configurations, and Teacher Assignments (Sept. 2011) Hamilton Project, Brookings Inst., pp. 5-11, 21, n. 7.) “This impact is equivalent to an additional two months of schooling.” (Policy Brief, Organizing Schools to Improve Student Achievement: Start Times, Grade Configurations, and Teacher Assignments (Aug. 2011) Brookings Inst., Hamilton Project, p. 4.). Individual student lifetime earnings are expected to increase by approximately $17,500 in present value. (Jacob & Rockoff, Organizing Schools to Improve Student Achievement: Start Times, Grade Configurations, and Teacher Assignments, supra, Hamilton Project, Brookings Inst., pp. 5-11.)

On August 25, 2014, the American Academy of Pediatrics formally recommended that middle school students begin classes no earlier than 8:30 a.m. (Adolescent Sleep Working Group, Committee on Adolesence, & Council on School Health, School Start Times for Adolescents (Aug. 25, 2014) Pediatrics, p. 647, Recommendation no. 4.)