Literature Review

This is a sampling of research we reviewed. We reviewed literature in support of later start times and against (there is far less literature on that).

• Adolescent Sleep Working Group. "School start times for adolescents." Pediatrics 134.3 (2014): 642-649.(http://pediatrics.aappublications.org/content/134/3/642.short )
  • See abstract, below.
• Carroll, Aaron. "The Economic Case for Letting Teenagers Sleep a Little Later." NY Times. Sept 13, 2017
• Danner, Fred, and Barbara Phillips. "Adolescent sleep, school start times, and teen motor vehicle crashes." Journal of clinical sleep medicine: JCSM: official publication of the American Academy of Sleep Medicine 4.6 (2008): 533.
  • Key findings: "Average crash rates for teen drivers in the study county in the 2 years after the change in school start time dropped 16.5%, compared with the 2 years prior to the change, whereas teen crash rates for the rest of the state increased 7.8% over the same time period."
• Dunietz, Galit Levi, et al. "Later school start times: what informs parent support or opposition?." Journal of Clinical Sleep Medicine: JCSM: Official Publication of the American Academy of Sleep Medicine 13.7 (2017): 889. (http://jcsm.aasm.org/ViewAbstract.aspx?pid=31048)
  • Key findings: "Overall, 88% of parents reported school start times before 8:30 am... In this group, 51% expressed support for later school start times. Support was associated with current school start times before 7:30 am; parental opinion that their teen's current school start time was “too early”; and agreement with American Academy of Pediatrics recommendations about school start times. Support also was associated with anticipation of improved school performance or increased sleep duration with later school start times. Conversely, parents who anticipated too little time for after-school activities and need for different transportation plans were often less supportive.
• Eccles, Jacquelynne S., and Robert W. Roeser. "Schools as developmental contexts during adolescence." Journal of research on adolescence 21.1 (2011): 225-241.
• Gariépy, Geneviève, et al. "School start time and sleep in Canadian adolescents." Journal of sleep research 26.2 (2017): 195-201.
  • Key findings: "Every 10‐min delay in school start time corresponded with 3.2 additional minutes of sleep, a 1.6% greater probability of sufficient sleep and a 2.1% smaller probability of feeling tired at school in the morning. Students from schools that started later slept longer, were more likely to meet sleep recommendations and were less likely to report feeling tired in the morning."
• Malone, Susan Kohl. "Early to bed, early to rise? An exploration of adolescent sleep hygiene practices." The Journal of School Nursing 27.5 (2011): 348-354.
• Melzer, Lisa. The Science Behind Changing Start Times. 2017. https://littletonpublicschools.net/sites/default/files/The%20Science%20Behind%20Changing%20School%20Start%20Times%20-%20Dr%20Meltzer%20to%20BOE%202017.09.14_0.pdf
• Owens, Judith A., Katherine Belon, and Patricia Moss. "Impact of delaying school start time on adolescent sleep, mood, and behavior." Archives of pediatrics & adolescent medicine 164.7 (2010): 608-614.
  • Key findings: After changing school start time at a private school in Rhode Island, "mean school night sleep duration increased by 45 minutes, and average bedtime advanced by 18 minutes (95% confidence interval, 7-29 minutes [t₄₂₃ = 3.36; P < .001]); the percentage of students getting less than 7 hours of sleep decreased by 79.4%, and those reporting at least 8 hours of sleep increased from 16.4% to 54.7%. Students reported significantly more satisfaction with sleep and experienced improved motivation. Daytime sleepiness, fatigue, and depressed mood were all reduced. Most health-related variables, including Health Center visits for fatigue-related complaints, and class attendance also improved."
• Wahistrom, Kyla. "Changing times: Findings from the first longitudinal study of later high school start times." NASSP Bulletin 86.633 (2002): 3-21.
  • Key findings: In the early 1990s, medical research found that teenagers have biologically different sleep and wake patterns than the preadolescent or adult population. On the basis of that information, in 1997 the seven comprehensive high schools in the Minneapolis Public School District shifted the school start timefrom 7:15 a. m. to 8:40 a. m. This article examines that change, finding significant benefits such as improved attendance and enrollment rates, less sleeping in class, and less student-reported depression. Policy implications are briefly discussed, acknowledging this to be a highly charged issue in school districts across the United States.
• Wolfson, Amy R., et al. "Middle school start times: the importance of a good night's sleep for young adolescents." Behavioral sleep medicine 5.3 (2007): 194-209.
  • Key findings: "With the onset of adolescence, teenagers require 9.2 hr of sleep and experience a delay in the timing of sleep. In the “real world” with early school start times, however, they report less sleep, striking differences between their school-weekend sleep schedules, and significant daytime sleepiness. Prior studies demonstrated that high schoolers with later school starts do not further delay bedtimes but obtain more sleep due to later wake times. This study examined sleep–wake patterns of young adolescents attending urban, public middle schools with early (7:15 a.m.) versus late (8:37 a.m.) start times. Students (N = 205) were assessed at 2 time periods. Students at the late-starting school reported waking up over 1 hr later on school mornings and obtaining 50 min more sleep each night, less sleepiness, and fewer tardies than students at the early school. All students reported similar school-night bedtimes, sleep hygiene practices, and weekend sleep schedules."
• Perkinson-Gloor, Nadine, Sakari Lemola, and Alexander Grob. "Sleep duration, positive attitude toward life, and academic achievement: The role of daytime tiredness, behavioral persistence, and school start times." Journal of adolescence36.2 (2013): 311-318.
  • Sleeping less than an average of 8 h per night was related to more tiredness, inferior behavioral persistence, less positive attitude toward life, and lower school grades, as compared to longer sleep duration. Daytime tiredness and behavioral persistence mediated the relationship between short sleep duration and positive attitude toward life and school grades. Students who started school 20 min later received reliably more sleep and reported less tiredness.

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Meta analysis links:

• Cochrane review(2017): https://www.ncbi.nlm.nih.gov/pubmed/28670711
• Meta analysis concluding limited evidence for many assumed (2016) upsides: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5155204/

Some districts that changed school start times in Colorado (http://www.startschoollater.net/success-stories.html)

Academy School District 20

Beginning in the 2012-2013 school year, Academy School District 20 delayed high school classes that began as early as 7:05 a.m., to 7:45 a.m., with the Aspen Valley High School start time remaining at 8:55 a.m. Middle schools were delayed to times between 7:45 a.m. and 8:30 a.m.

Cherry Creek

Start times for high schools pushed back 65 minutes in school year 2017-18. Start times for high schools pushed back 65 minutes, middle schools will start an hour to 50 minutes later, and elementary schools begin 65 minutes earlier. (Elementary schools run 8am-2:45pm; middle schools 8:50 am-3:45pm; high schools 8:201m-3:30pm.) This change was budget-neutral.

Cortez-Montezuma Schools

An interim superintendent changed the previous 7:30 a.m. start to 8:50 a.m. for Cortez Middle School and the Montezuma-Cortez High School in 2012. The interim superintendent also at the same time changed the district’s four-day school week to a five-day week

Denver

When Denver’s new Northfield High School opens in August 2015, its students will report to their first class more than an hour later than students at most other district high schools. The school’s planned 8:45 a.m. start time is a nod to the growing body of evidence that suggest teens are hard-wired to favor later bedtimes and do better academically when school schedules accommodate their natural sleep cycles. In addition, back in 2005, Denver schools added 2 hours to HS day for flexibility. Students pick their own start and end times.

​Greeley-Evans School District

Beginning in August 2017, District 6 will move to a later start time for high schools, no earlier than 8 a.m. while middle school shift students to an earlier start time — 8:30 a.m. from 9 a.m. — and dismiss earlier so they aren't walking home in the dark during winter. The youngest students, who tend to be early risers anyway, will start school at 7:50 a.m.

Harrison School District

Starting in 2014, the Harrison School District near Colorado Springs pushed back start times at all 20 of its schools, after a committee studied the issue for two years. High schools now start at 7:45 a.m. instead of 7:20 a.m, and elementary and middle schools now start at 8:35 a.m. instead of 8:10 a.m. On Mondays only, middle schools start at 10:05 a.m. and high schools start at 9:15 a.m. They say they made these changes before the AAP recommendations were out and will continue to work toward starting high schools later.