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Cited by 311Sleep and related disordersSleep and Work-Related FatigueCircadian rhythm and melatonin

School Start Times, Sleep, Behavioral, Health, and Academic Outcomes: a Review of the Literature

Open access
Wheaton, Anne G., Chapman, Daniel P., Croft, Janet B.·2016·Journal of School Health
DOI 10.1111/josh.12388PMC PMC4824552
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Abstract

BACKGROUND: Insufficient sleep in adolescents has been shown to be associated with a wide variety of adverse outcomes, from poor mental and physical health to behavioral problems and lower academic grades. However, most high school students do not get sufficient sleep. Delaying school start times for adolescents has been proposed as a policy change to address insufficient sleep in this population and potentially to improve students' academic performance, reduce engagement in risk behaviors, and improve health. METHODS: This article reviews 38 reports examining the association between school start times, sleep, and other outcomes among adolescent students. RESULTS: Most studies reviewed provide evidence that delaying school start time increases weeknight sleep duration among adolescents, primarily by delaying rise times. Most of the studies saw a significant increase in sleep duration even with relatively small delays in start times of half an hour or so. Later start times also generally correspond to improved attendance, less tardiness, less falling asleep in class, better grades, and fewer motor vehicle crashes. CONCLUSIONS: Although additional research is necessary, research results that are already available should be disseminated to stakeholders to enable the development of evidence-based school policies.

Integrity signals

Registry

Crossref · 10.1111/josh.12388

Cites

88 of 88 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

45 of 224 cited sources checked · 34 supported · 0 flagged · accuracy not yet measured

  • Premisecitation

    Insufficient sleep in children and adolescents is associated with excess weight.

    “Insufficient sleep has been linked to excess weight,6–13 decreased physical activity,14 and increased food intake, possibly due to alterations in appetite-regulating hormones.12”
    Quote in the paperNot a substantial claim1 of 8 sources checked
    • cites [6] source

      Section 3.5 reports that shorter sleep was associated with greater odds of obesity among female US high school students. It found no significant association among male students, so the source does not establish the link across adolescents generally; the Conclusion also describes a negative association in younger children while noting inconsistencies across age groups. No page numbers are provided in our copy. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
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  • Premisecitation

    Longitudinal investigations of weight changes attributable to sleep duration have produced mixed results.

    “Results of investigations into longitudinal changes in weight attributable to sleep duration, however, have been mixed.10,15”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [10] source
    • cites [15] source
  • Premisecitation

    Insufficient sleep in adolescents is tied to suicidal ideation.

    “A solid body of literature has found that insufficient sleep in this young population is tied to poor mental health, including depression, depressive symptoms,8,16–22 and suicidal ideation.8,18,20,22–25”
    Quote in the paperSubstantial claim2 of 7 sources checked
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  • Premisecitation

    Insufficient sleep in adolescents is tied to poor mental health, including depression and depressive symptoms.

    “A solid body of literature has found that insufficient sleep in this young population is tied to poor mental health, including depression, depressive symptoms,8,16–22 and suicidal ideation.8,18,20,22–25”
    Quote in the paperSubstantial claim1 of 8 sources checked
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  • Premisecitation

    Short sleep duration is associated with a higher risk of unintentional injury.

    “Short sleep duration has also been found to be associated with a higher risk of unintentional injury.30”
    Quote in the paperNot a substantial claim1 of 1 sources checked
  • May combine two claims. 39
  • Classified as probably not a substantial claim. 20

  • May combine two claims.

    Premisecitation

    Students who do not get enough sleep may be more likely to have attention problems and poor academic performance, although not all research agrees.

    “Finally, students who do not get enough sleep also may be more likely to have problems paying attention and poor academic performance,17,21,31–36 although not all research agrees.37,38”
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  • May combine two claims.

    Premisecitation

    External factors contributing to later bedtimes among adolescents include increased schoolwork, afterschool activities including employment, fewer parent-set bedtimes, and late-night technology use in the bedroom.

    “External factors that contribute to later bedtimes among adolescents include an increase in schoolwork; participation in afterschool activities, including employment; fewer parent-set bedtimes; and late-night use of technology in the bedroom.39–43”
    Quote in the paperNot a substantial claim2 of 5 sources checked
    • cites [39] source
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    • cites [42] source

      The Introduction links later adolescent bedtimes to increased academic workload, part-time employment, and technology use, particularly in the bedroom. The Results and Discussion associate parent-set bedtimes with earlier bedtimes. The paper does not establish that afterschool activities generally, beyond employment, contribute to later bedtimes; its comparison of extracurricular commitments was between bedtime-setting groups, not a test of that claim. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [43] source

      The Results section (page not provided) associates more time spent working, using computers, and socializing with later bedtimes among US adolescents aged 15–17. It reports minimal effects for hours in school and does not establish increased schoolwork, fewer parent-set bedtimes, or technology use specifically in the bedroom. The Discussion also cautions that the activity associations do not establish causation. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Findingcitation

    In further analysis, Paksarian et al. found longer sleep duration for boys only, 20 minutes for each 30-minute delay, and variation by urbanicity.

    “In further analysis, the authors found the longer sleep duration for boys only (20 minutes for each 30 minute delay in school start times) and that there was variation by urbanicity, with an increase in sleep duration for boys in major metropolitan”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [71] source

      The Results (Interaction by Sex) report about 20 additional minutes of sleep for boys, but only for each 30-minute delay in start times before 8:01 am; no association was found from 8:01 am onward or for girls. The Results (Interaction by Urbanicity) also report variation by urbanicity, including increased sleep duration for boys in major metropolitan counties. The citing sentence omits the before-8:01-am limit on its 20-minute figure. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • Rests on an assumption: The 38 reviewed reports are sufficiently comparable in design, measures, and populations to be synthesized into general conclusions about school start times.

  • May combine two claims.

    Findingcitation

    Paksarian et al. observed longer sleep durations with later school start times, 11 minutes for each 30-minute delay, but only for schools that started before 8:01 AM.

    “Paksarian et al. observed longer sleep durations with later school start times (11 minutes for each 30 minute delay in school start times), but only for schools that started before 8:01 AM.71”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • Rests on an assumption: The 38 reviewed reports are sufficiently comparable in design, measures, and populations to be synthesized into general conclusions about school start times.

  • May combine two claims.

    Findingcitation

    Evidence points to a positive link between later start times and academic performance, but the link may be weak and inconsistent.

    “some evidence suggests a positive association between later school start time and academic performance,57,58,60,61,64,81 although the association may be relatively weak55 and not universal.59,67,80”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites [57] source
    • cites [58] source
    • cites [60]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • Rests on an assumption: Grades are not standardized and differ across subjects, teachers, and schools.
    • Rests on an assumption: Not all students take standardized tests like the SAT or ACT, and those who do are more likely to be college-bound.
    • Rests on an assumption: Students who already perform very well before a start time delay have little room to improve.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    Minnesota high school graduates' annual ACT participation ranged from 59% to 66% between 1993 and 2002.

    “The annual ACT participation rate among Minnesota high school graduates varied from 59% to 66% during the study period (1993–2002).59”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [59] source

      In A. Data and Empirical Methods (p. 6), the paper reports annual ACT participation among Minnesota high school graduates ranging from 59% to 66%. It gives the participation-rate period as 1994–2002, not 1993–2002; the ACT test-score data begin in the 1993–94 school year. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Greater work time has been associated with worse academic performance.

    “More time working has been linked to poorer academic performance.89”
    Quote in the paperNot a substantial claim1 of 1 sources checked

  • May combine two claims.

    Findingcitation

    The next year, 16-17 year old crash rates were higher (p < .05) in that county, but including 18 year olds made the difference non-significant (p = 0.09).

    “The following year, crash rates among 16–17 year olds were higher (p < .05) in the same county, but difference was not statistically significant when 18 year olds were included in comparison (p = 0.09).88”
    Quote in the paperNot a substantial claim1 of 1 sources checked

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Findingnone given

    Delaying school start time increases weeknight sleep duration among adolescents, mainly by delaying rise times.

    “Most studies reviewed provide evidence that delaying school start time increases weeknight sleep duration among adolescents, primarily by delaying rise times.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The 38 reviewed reports are sufficiently comparable in design, measures, and populations to be synthesized into general conclusions about school start times.

  • May combine two claims.

    Findingcitation

    For one of these studies, the sleep duration difference did not meet the authors' effect size criterion, though a large difference was not expected because the start time difference was only 20 minutes.

    “For one of these, the difference in sleep duration did not meet the authors’ effect size criterion, although the difference would not have been expected to be large since the difference in school start times was only 20 minutes.35”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [35] source
    • Rests on an assumption: The 38 reviewed reports are sufficiently comparable in design, measures, and populations to be synthesized into general conclusions about school start times.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    In Owens et al., some students reported that after seeing benefits of more sleep from delayed start times, they tried to increase sleep further by going to bed earlier.

    “In the study by Owens et al., some students stated that after seeing the benefits of getting more sleep with the delay in school start times, they sought to further increase their sleep by going to bed earlier.65”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [65] source
    • Rests on an assumption: The 38 reviewed reports are sufficiently comparable in design, measures, and populations to be synthesized into general conclusions about school start times.

  • May combine two claims.

    Findingcitation

    Seven reports showed greater weekend catch-up sleep with earlier start times, but one report found no such difference.

    “Seven reports that evaluated weekend sleep patterns found more “catch-up” sleep on the weekends for earlier start times,51,61,64,66,69,74,78 although one found no difference in this outcome.71”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [51]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [61]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [64] source
    • Rests on an assumption: A gap between school-night and weekend sleep can signal that students are not getting enough sleep on school nights and are compensating on weekends.

  • May combine two claims.

    Findingcitation

    The other study observed longer sleep duration for students at the later starting school, but the difference was not statistically significant.

    “The other study observed longer sleep duration for students at the later starting school, but the difference was not statistically significant.50”
    Quote in the paperNot a substantial claim0 of 1 sources checked
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      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • Rests on an assumption: The 38 reviewed reports are sufficiently comparable in design, measures, and populations to be synthesized into general conclusions about school start times.

  • May combine two claims.

    Findingcitation

    Wahlstrom and colleagues' survey after a start time change found that 27% of students had fallen asleep in a morning class and 29% in an afternoon class within the prior two weeks.

    “In Wahlstrom and colleagues’ survey of students post-start time change, 27% reported falling asleep in a morning class in the previous 2 weeks, and 29% fell asleep in an afternoon class.61”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [61]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Findingcitation

    When start time moved earlier from 8:25 to 7:20, students showed reduced REM sleep latency and reduced sleep latency.

    “After an advance in start time from 8:25 AM to 7:20 AM, students had a shorter REM sleep latency (time between sleep onset and onset of REM sleep) on polysomnography and a shorter sleep latency (time to sleep onset during a standard testing protocol).62”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [62] source

  • May combine two claims.

    Findingcitation

    Sleep duration for the second later-starting district was also longer than for the early-starting district, but the difference was not statistically significant.

    “Sleep duration for the second later-starting district was also longer than for the early-starting district, but the difference was not statistically significant.60”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [60]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • Rests on an assumption: The 38 reviewed reports are sufficiently comparable in design, measures, and populations to be synthesized into general conclusions about school start times.

  • May combine two claims.

    Findingcitation

    Wahlstrom and colleagues reported fewer homework hours with later start times, Edwards found the reverse, and Boergers and colleagues found no difference.

    “Wahlstrom and colleagues found that students with later school start times reported less hours of homework,60 whereas Edwards observed the reverse57 and Boergers and colleagues saw no difference.67”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [60]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [57] source
    • cites [67] source

  • May combine two claims.

    Findingcitation

    A single study found longer weeknight sleep and unchanged weekend sleep after a start time delay.

    “One study assessed weeknight and weekend sleep and observed longer weeknight sleep duration and no change in weekend sleep patterns after a delay in school start time”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [67] source

  • May combine two claims.

    Findingcitation

    The longitudinal part of that report associated a one-hour delay with a 2 percentile math gain and a 1.5 percentile reading gain.

    “The longitudinal component of the same report looked at schools that had changed school start times over the course of the study and found that a one hour delay in start time corresponded to a 2 percentile increase in math and 1.5 percentile increase in reading.57”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [57] source

  • May combine two claims.

    Findingcitation

    Wolfson and colleagues found higher grades after start time delays in 8th grade, but not in 7th grade.

    “Wolfson and colleagues observed higher grades after delaying school start times for 8th grade, although not for 7th-grade students.64”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [64] source

  • May combine two claims.

    Findingcitation

    In the Norwegian Monday-delay study, the delayed-start school showed fewer lapses and faster Monday reaction times than Friday, unlike controls.

    “The Norwegian study that delayed start times on Mondays included reaction time tests and found that students at the school with delayed start time had significantly fewer lapses and faster reaction times on Monday than Friday compared to no difference among students at the control (no delay) school.78”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [78] source

  • May combine two claims.

    Findingcitation

    Arlington Public Schools saw better first-period grades for 10th graders after a 45-minute high school delay, but no change for 7th graders after a 20-minute middle school advance.

    “Arlington Public Schools (Arlington County, Virginia) observed an improvement in 10th grade students’ 1st period grades after a 45 minute delay in high school start times, with no change in 7th grade students’ 1st period grades after a 20 minute advance in middle school start times.81”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [81]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    One study found less school-week work time among students at later-starting schools (p < .05).

    “One study saw that students at schools with later start times spent less time at work during the school week (p < .05).60”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [60]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Findingcitation

    Even with lower attendance, those 10th graders' academic performance improved.

    “Despite this finding, academic performance improved for those students.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [81]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Findingnone given

    Not every study showed better academics with later start times, but none showed a negative academic effect.

    “Although not all studies found that later start times corresponded to improved academic performance, no studies found a negative impact of later school start times on academics.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    Later start times were generally linked to better attendance, less tardiness, less in-class sleep, fewer depression symptoms, and fewer crashes.

    “Later school start times also generally corresponded to improved attendance, less tardiness, less falling asleep in class, fewer depression symptoms, and fewer motor vehicle crashes.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    Almost all studies indicate that later start times raise adolescent sleep duration, mainly by shifting wake times later.

    “Nearly all studies to date provide evidence that delaying school start time accomplishes the goal of increasing sleep duration among these students, primarily by delaying rise times.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Adolescents as a group are largely sleep-deprived.

  • May combine two claims.

    Findingcitation

    Wahlstrom and colleagues found that among four areas, two had major teen crash reductions (≥65%) after delays, one had a 6% decrease, and one had a 9% increase.

    “Two areas saw major decreases (≥65%) in teen crash rates after the delays, while one saw a small decrease (6%), and another saw a small increase (9%).61”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [61]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    The proportion of students getting 8 or more hours of sleep decreases with school grade level, with fewer than one quarter of high school seniors getting that amount.

    “Less than a third of students report 8 or more hours of sleep, and this proportion decreases as school grade level increases so that fewer than a quarter of high school seniors get this amount.4”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [4] source

  • May combine two claims.

    Premisecitation

    Puberty alters circadian rhythms such that adolescents are more alert in the afternoons and evenings and require morning sleep.

    “One of the early changes associated with puberty is alteration of a child’s circadian rhythms, such that adolescents are more alert in the afternoons and evenings and require morning sleep.44”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [44] source

  • May combine two claims.

    Premisereasoning

    That study used a non-standardized measure of academic performance and did not adjust for grade in school, which is strongly related to insufficient sleep prevalence.

    “That study also relied on a non-standardized measure of academic performance and did not adjust for variables such as grade in school, which is strongly related to prevalence of insufficient sleep.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    School-based sleep promotion programs may improve sleep knowledge without significantly affecting behavior.

    “However, these programs may improve knowledge of sleep without having a significant effect on behavior.45,46”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [45] source
    • cites [46] source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisereasoning

    Cross-sectional studies can show only associations between school start times and other variables, not cause and effect.

    “However, as with all cross- sectional studies, only associations between school start times and other variables can be shown—not cause and effect.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Premisenone given

    Class grading and grade point averages are not standardized and may vary by subject, teacher, and school.

    “However, class grading and subsequently grade point averages are not standardized and may vary by subject, teacher, and school.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    In 2014, the American Academy of Pediatrics published a policy statement urging middle and high schools to adjust start times to permit adequate sleep and improve health, safety, academic performance, and quality of life.

    “In 2014, the American Academy of Pediatrics published a policy statement urging middle and high schools to adjust start times to permit students to obtain adequate sleep and improve physical and mental health, safety, academic performance, and quality of life.3”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [3] source

  • May combine two claims.

    Premisereasoning

    That negative study did not adjust for student sex, which was a strong predictor of grade point average.

    “That study also did not adjust by sex of student, which was a strong predictor of grade point average.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisereasoning

    Longitudinal studies may provide stronger evidence of causation than cross-sectional studies by addressing temporality.

    “Although longitudinal studies may provide stronger evidence of causation than cross-sectional studies by addressing the issue of temporality, it is”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    Publication bias and over-representation of studies with significant results are possible in this review.

    “Publication bias and over-representation of studies with significant results is also possible, however, some studies included in this review had results that did not agree with the majority.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    Other school characteristics, such as student socioeconomic status, can affect sleep and other outcomes but are often not reported.

    “Other school characteristics, such as socioeconomic status of students, can also have effects on sleep and other outcomes but is often not reported.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    The Norwegian study shifted Monday start times from 8:30 to 9:30.

    “In the Norwegian study,78 start times were delayed from 8:30 AM to 9:30 AM on Mondays only.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [78] source

  • May combine two claims.

    Interpretationcitation

    Both findings point to sleep deficiency.

    “Both of these results indicate sleep-deficiency.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    The null result in Norway might stem from the delay applying only one day per week or from the original start time already being sufficiently late.

    “The lack of association could have been due to either the change being in effect only one day a week or the earlier start time already being late enough.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    In the Croatian study, schools switched weekly between morning and afternoon schedules.

    “the schools in the Croatian study alternated their schedule weekly, with schools starting in the morning one week and in the afternoon the next.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [80]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    That Croatian study reported that girls had a later chronotype and greater sleepiness.

    “That study found that girls had later chronotype (evening preference) and more sleepiness.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [80]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Study design and conductcitation

    The Croatian study's earlier-starting schools had mostly male students, whereas later-starting schools had mostly female students.

    “In the Croatian study,80 the students at the earlier starting schools were predominantly boys, while girls made up most of the population at the later starting schools.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [80]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Study design and conductcitation

    That Croatian study had different student compositions, students knew their schedule when enrolling, and response rates were low.

    “However, in addition to the difference in the make-up of the student populations (more boys at earlier schools and more girls at later schools) in that study, students were also aware of the school schedule at enrollment and the response rate was low.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [80]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    That pattern might indicate less catch-up sleep.

    “which could be interpreted as a decrease in “catch-up” sleep.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: A gap between school-night and weekend sleep can signal that students are not getting enough sleep on school nights and are compensating on weekends.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    That study did not analyze the weeknight-weekend sleep difference.

    “However, the difference between weeknight and weekend sleep was not analyzed.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [67] source

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationreasoning

    The extra napping was presumably an attempt to compensate for inadequate nighttime sleep.

    “presumably in an attempt to make up for insufficient nighttime sleep.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    That study delayed start time only on Mondays.

    “However, in that study, the start time was delayed on Mondays only.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [78] source

  • May combine two claims.

    Study design and conductcitation

    That start time study was cross-sectional, and factors like socioeconomic status might account for the work-time difference.

    “However, the start time study was cross-sectional and other variables such as socioeconomic status may explain the difference in time spent at work.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [60]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Evidence supports a causal link between insufficient sleep and depression, and with mood more broadly.

    “there is also evidence of a causal relationship between insufficient sleep and depression, as well as mood in general.84,85”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [84] source
    • cites [85]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Shorter REM sleep latency, as Carskadon and colleagues saw after an earlier start time, is also common in major depression.

    “Incidentally, shorter REM sleep latency, such as was observed by Carskadon and colleagues after an advance in start time,62 is also often observed in major depression.86”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [86] source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    The Arlington report noted a change in attendance reporting procedures during the study.

    “The report also noted that the attendance reporting procedures changed during the course of the study.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [81]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

54 of 54

  • The paper relies on this without support.

    The adverse outcomes linked to insufficient sleep are caused by insufficient sleep, so increasing sleep through later school start times would improve those outcomes.

    “Delaying school start times for adolescents has been proposed as a policy change to address insufficient sleep in this population and potentially to improve students’ academic performance, reduce engagement in risk behaviors, and improve health.”

  • The paper relies on this without support.

    The 38 reviewed reports are sufficiently comparable in design, measures, and populations to be synthesized into general conclusions about school start times.

    “This paper reviews 38 reports examining the association between school start times, sleep, and other outcomes among adolescent students.”

  • The paper relies on this without support.

    A gap between school-night and weekend sleep can signal that students are not getting enough sleep on school nights and are compensating on weekends.

    “Differences in sleep patterns between weeknights and weekend nights can also indicate insufficient weeknight sleep as students try to make up for lost sleep on the weekends.”

  • The paper relies on this without support.

    Adolescents who are sleepy might use caffeine to counteract their sleepiness.

    “Sleepy adolescents may also attempt to lessen sleepiness with caffeine.”

  • The paper relies on this without support.

    Grades are not standardized and differ across subjects, teachers, and schools.

    “Class grading is not standardized and varies by subject, teacher, and school.”

  • The paper relies on this without support.

    Not all students take standardized tests like the SAT or ACT, and those who do are more likely to be college-bound.

    “Standardized tests such as the Scholastic Aptitude Test or the ACT are not taken by all students and are more likely to be taken by students planning to attend college.”

  • The paper relies on this without support.

    Students who already perform very well before a start time delay have little room to improve.

    “Finally, students with very good academic performance before a delay in school start time do not have much room for improvement.”

  • The paper relies on this without support.

    Attendance matters for academic success.

    “School attendance is also important for academic success.”

  • The paper relies on this without support.

    Biological changes begin before high school.

    “Much of the focus has been on high school students, but biological changes begin earlier, so further research into middle-school students is warranted.”

  • The paper relies on this without support.

    Adolescents as a group are largely sleep-deprived.

    “Delaying school start times for adolescents has been proposed as a policy change to address insufficient sleep among adolescents, a largely sleep-deprived population”
10 of 10

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Delayed start times and receiving more sleep as a result may lead to fewer car crash rates and unintentional injury.

    “Several studies have also examined the effect of later start times on car crash and unintentional injury rates among adolescents and found that delayed start times and receiving more sleep as a result may lead to fewer car crash rates and unintentional injury [68,107], most likely through reduced sleepiness [68, 70, 73, 76, 77•, 78•, 79, 80].”

    From Later School Start Times as a Public Health Intervention to Promote Sleep Health in Adolescents (2023) · cites this paper as [68]

    The Literature Review sections on Motor Vehicle Crashes and Sleep and Sleepiness report that later starts were generally associated with more sleep and, in several settings, lower teen crash rates. The Background links short sleep to unintentional injury, but the review does not report that delaying school starts reduced unintentional injury rates. Page numbers were not available in our copy. (LLM, conf=0.87)

    Experimental — accuracy not yet measured

  • The associations between later school start times and academic performance may be mediated by reduced sleepiness and improved attention during the school day, particularly among high school students.

    “The associations between later school start times and academic performance may be mediated by reduced sleepiness [68, 70, 73, 76, 77•, 78•, 79, 80] and improved attention during the school day [88], particularly among high school students [76].”

    From Later School Start Times as a Public Health Intervention to Promote Sleep Health in Adolescents (2023) · cites this paper as [68]

    The review’s Sleep and Sleepiness and Academics and Cognition sections report less daytime sleepiness, fewer attention problems, and some academic gains with later start times. They do not establish that sleepiness or attention mediates the academic association, or that this pathway is particularly strong among high school students. Page numbers were not available in our copy. (LLM, conf=0.82)

    Experimental — accuracy not yet measured

  • Later school start times are consistently associated with longer sleep durations on school nights, primarily due to shifting rise times later.

    “Growing evidence suggests that adolescents at later-starting schools sleep longer on weekdays, have higher attendance and graduation rates, and fewer mental health symptoms compared to their peers at earlier-starting schools.”

    From Later School Start Times as a Public Health Intervention to Promote Sleep Health in Adolescents (2023) · cites this paper as [68]

  • A review by Wheaton et al. found less reported daytime sleepiness or falling asleep in class in schools with later start times in 10 out of 12 reviewed studies.

    “a review of school start time studies by Wheaton et al. found less reported daytime sleepiness or falling asleep in class in schools with later start times in 10 out of 12 reviewed studies [68].”

    From Later School Start Times as a Public Health Intervention to Promote Sleep Health in Adolescents (2023) · cites this paper as [68]

  • Preliminary findings show better dietary quality and more healthful weight behaviors of students attending delayed-start schools compared to their peers.

    “the preliminary findings show better dietary quality and more healthful weight behaviors of students attending delayed-start schools compared to their peers [68,105,106].”

    From Later School Start Times as a Public Health Intervention to Promote Sleep Health in Adolescents (2023) · cites this paper as [68]

    The Background (page unavailable) links insufficient sleep—not delayed school start times—to excess weight, increased food intake, and unhealthy weight-control strategies. The Literature Review’s Other Outcomes section (page unavailable) does not report a comparison of dietary quality or weight behaviors between students at delayed-start schools and their peers. Searches for dietary quality and weight-control behaviors found no such comparison in our copy. (LLM, conf=0.75)

    Experimental — accuracy not yet measured

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Conclusion claims no negative academic effects, but body text reports worse academics in one study

    Major

    The conclusion says later start times never harmed academic performance. Elsewhere, the review says one study found students at earlier-starting schools performed better academically than those at later-starting schools, which contradicts that blanket statement.

  • Academic conclusion overlooks a contrary finding

    Major

    The review describes a study in which students at earlier-starting schools performed better academically, but its conclusion says no study found a negative academic result for later starts.

  • Reference-list count conflicts with the reports named

    Minor

    The methods say that references 50-54 and 55-59 were identified through reference lists, and that Step E added another report. That is more than the five reports later said to have been identified this way.

3 of 3

Cites

Flagged first, then by citations

3 of the 91 references couldn’t be matched to a known paper.

Research works printed but not linked: 6

  1. Allen RP, 1989, Self‐reported sleep‐wake patterns for students during the school year from two different senior high schools, Sleep Res, 21, 114
  2. Allen RP, 1992, Social factors associated with the amount of school week sleep lag for seniors in a early starting suburban high school, Sleep Res, 21, 114
  3. Kowalski NA, 1995, School sleep lag is less but persists with a very late starting high school, Sleep Res, 24, 124
  4. Carskadon MA, 1995, Early school schedules modify adolescent sleepiness, Sleep Res, 24, 92
  5. Wolfson AR, 1995, Sleep, behavior, and stress at the transition to senior high school, Sleep Res, 24, 115
  6. Wahlstrom K, 2014, Examining the Impact of Later School Start Times on the Health and Academic Performance of High School Students: a Multi‐Site Study. Center for Applied Research and Educational Improvement

Cited by

Sorted by citations

Related

Authors
Wheaton, A. G., Chapman, D. P., & Croft, J. B.
Affiliations
Centers for Disease Control and Prevention (US)
Corresponding author
Wheaton, Anne G.
ORCID
Venue
Journal of School Health
Publisher
Wiley
Published
2016-04-03
Volume
86
Issue
5
Pages
363-381
ISSN
  • 0022-4391 (ISSN-L)
  • 1746-1561
DOI
10.1111/josh.12388
PMC
PMC4824552
OpenAlex
W2318249357
Cited by
311
References
91
Citations by year
2026: 23 · 2025: 29 · 2024: 25 · 2023: 39 · 2022: 42 · 2021: 37 · 2020: 38 · 2019: 28 · 2018: 24 · 2017: 19 · 2016: 7
FWCI
3.41
Type
journal article
Language
en
Open access
Licence
onlinelibrary.wiley.com/termsAndConditions#vor (vor)
Locations
  • Journal of School Health (publishedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (acceptedVersion)
Funders
National Institutes of Health (CC999999)
Topics
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Sleep and related disorders
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Sleep and Work-Related Fatigue
  • Life Sciences › Neuroscience › Endocrine and Autonomic Systems › Circadian rhythm and melatonin
Keywords
school start time, adolescent sleep, sleep duration, academic performance, school attendance, tardiness, risk-taking, traffic accidents, school policy
MeSH terms
Absenteeism, Accidents, Traffic, Adolescent, Child, Cognition, Educational Status, Health Status, Humans, Mental Health, Schools, Sleep, Time Factors, Wakefulness, Young Adult

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read under definition version 3 (extract-v3) on 2026-09-28.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-09-28.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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