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

In the paper

“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”

What the sources say

• ?Not checked — no full text of the sourcecites [17] source
• ?Not checked — no full text of the sourcecites [21] source
• Supported

  The Discussion reports a pathway in teenagers from short sleep duration through daytime somnolence and reduced attention to lower academic achievement. The Conclusions likewise report correlations among these variables. The citing sentence uses tentative language; its caveat that not all research agrees is attached to other citations, not this source. (LLM, conf=0.92)

  cites [31] source
• ?Not checked — no full text of the sourcecites [32] source
• ?Not checked — no full text of the sourcecites [33] source
• ?Not checked — no full text of the sourcecites [34] source
• ?Not checked — no full text of the sourcecites [35] source
• Supported

  The Introduction links insufficient sleep to attention problems, and the Results report that children sleeping under nine hours had higher odds of poor academic achievement. The Discussion says daytime sleepiness and, in some cases, short sleep duration were associated with impaired attention and achievement. The citing sentence assigns the qualification about research disagreement to other citations. (LLM, conf=0.92)

  cites [36] source
• ?Not checked — no full text of the sourcecites [37] source
• Supported

  The Discussion links sleep deprivation with reduced alertness and reports poorer school performance among students who did not make up weekday sleep loss. The paper qualifies the performance finding: short weekday sleep alone was not associated with poorer performance, whereas chronic sleep deprivation was. The claim’s ‘may’ is consistent with that qualification; its ‘not all research agrees’ caveat is attached to other citations. (LLM, conf=0.88)

  cites [38] source

In the paper

“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”

What the sources say

• ?Not checked — no full text of the sourcecites [39] source
• ?Not checked — no full text of the sourcecites [40] source
• ?Not checked — no full text of the sourcecites [41] source
• Partly supported

  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)

  cites [42] sourceExperimental — accuracy not yet measured
• Partly supported

  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)

  cites [43] sourceExperimental — accuracy not yet measured

In the paper

“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”

What the sources say

• Partly supported

  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)

  cites [71] sourceExperimental — accuracy not yet measured

In the paper

“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”

What the sources say

• Supported

  The Discussion reports an estimate of about 11 additional minutes of sleep per 30-minute later start before 8:01 am. It also describes a plateau beyond 8:01 am, matching the claim's qualification. (LLM, conf=0.94)

  cites [71] source

In the paper

“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”

What the sources say

• ?Not checked — no full text of the sourcecites [57] source
• Supported

  The paper supports the positive-link portion of the sentence: on p. 2, the authors report that later school starts significantly improve academic achievement. The sentence assigns the 'relatively weak' and 'not universal' qualifications to other citations, not necessarily to this paper. (LLM, conf=0.92)

  cites [58] source
• ?Not matched

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

  cites [60]

In the paper

“The annual ACT participation rate among Minnesota high school graduates varied from 59% to 66% during the study period (1993–2002).59”

What the sources say

• Partly supported

  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)

  cites [59] sourceExperimental — accuracy not yet measured

In the paper

“More time working has been linked to poorer academic performance.89”

What the sources say

• Supported

  The Results report that adolescents had lower GPAs when working intensive hours than when not working. The claim describes an association, not a causal effect, and is consistent with that finding. (LLM, conf=0.94)

  cites [89] source

In the paper

“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”

What the sources say

• Supported

  Table 1 (page not provided) reports that in 2010–2011 Chesterfield County had a higher crash rate than Henrico County among 16–17-year-olds (p = 0.046). The difference for 16–18-year-olds was not statistically significant (p = 0.088), rounded to 0.09 in the Results. (LLM, conf=0.94)

  cites [88] source

In the paper

“Most studies reviewed provide evidence that delaying school start time increases weeknight sleep duration among adolescents, primarily by delaying rise times.”

In the paper

“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”

What the sources say

• ?Not checked — no full text of the sourcecites [35] source

In the paper

“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”

What the sources say

• ?Not checked — no full text of the sourcecites [65] source

In the paper

“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”

What the sources say

• ?Not matched

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

  cites [51]
• ?Not matched

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

  cites [61]
• ?Not checked — no full text of the sourcecites [64] source

In the paper

“The other study observed longer sleep duration for students at the later starting school, but the difference was not statistically significant.50”

What the sources say

• ?Not matched

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

  cites [50]

In the paper

“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”

What the sources say

• ?Not matched

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

  cites [61]

In the paper

“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”

What the sources say

• ?Not checked — no full text of the sourcecites [62] source

In the paper

“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”

What the sources say

• ?Not matched

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

  cites [60]

In the paper

“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”

What the sources say

• ?Not matched

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

  cites [60]
• ?Not checked — no full text of the sourcecites [57] source
• ?Not checked — no full text of the sourcecites [67] source

In the paper

“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”

What the sources say

• ?Not checked — no full text of the sourcecites [67] source

In the paper

“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”

What the sources say

• ?Not checked — no full text of the sourcecites [57] source

In the paper

“Wolfson and colleagues observed higher grades after delaying school start times for 8th grade, although not for 7th-grade students.64”

What the sources say

• ?Not checked — no full text of the sourcecites [64] source

In the paper

“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”

What the sources say

• ?Not checked — no full text of the sourcecites [78] source

In the paper

“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”

What the sources say

• ?Not matched

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

  cites [81]

In the paper

“One study saw that students at schools with later start times spent less time at work during the school week (p < .05).60”

What the sources say

• ?Not matched

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

  cites [60]

In the paper

“Despite this finding, academic performance improved for those students.”

What the sources say

• ?Not matched

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

  cites [81]

In the paper

“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.”

In the paper

“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.”

In the paper

“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.”

In the paper

“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”

What the sources say

• ?Not matched

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

  cites [61]

In the paper

“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”

What the sources say

• ?Not checked — no full text of the sourcecites [4] source

In the paper

“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”

What the sources say

• ?Not checked — no full text of the sourcecites [44] source

In the paper

“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.”

In the paper

“However, these programs may improve knowledge of sleep without having a significant effect on behavior.45,46”

What the sources say

• ?Not checked — no full text of the sourcecites [45] source
• ?Not checked — no full text of the sourcecites [46] source

In the paper

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

In the paper

“However, class grading and subsequently grade point averages are not standardized and may vary by subject, teacher, and school.”

In the paper

“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”

What the sources say

• ?Not checked — no full text of the sourcecites [3] source

In the paper

“That study also did not adjust by sex of student, which was a strong predictor of grade point average.”

In the paper

“Although longitudinal studies may provide stronger evidence of causation than cross-sectional studies by addressing the issue of temporality, it is”

In the paper

“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.”

In the paper

“Other school characteristics, such as socioeconomic status of students, can also have effects on sleep and other outcomes but is often not reported.”

In the paper

“In the Norwegian study,78 start times were delayed from 8:30 AM to 9:30 AM on Mondays only.”

What the sources say

• ?Not checked — no full text of the sourcecites [78] source

In the paper

“Both of these results indicate sleep-deficiency.”

In the paper

“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.”

In the paper

“the schools in the Croatian study alternated their schedule weekly, with schools starting in the morning one week and in the afternoon the next.”

What the sources say

• ?Not matched

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

  cites [80]

In the paper

“That study found that girls had later chronotype (evening preference) and more sleepiness.”

What the sources say

• ?Not matched

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

  cites [80]

In the paper

“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.”

What the sources say

• ?Not matched

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

  cites [80]

In the paper

“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.”

What the sources say

• ?Not matched

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

  cites [80]

In the paper

“which could be interpreted as a decrease in “catch-up” sleep.”

In the paper

“However, the difference between weeknight and weekend sleep was not analyzed.”

What the sources say

• ?Not checked — no full text of the sourcecites [67] source

In the paper

“presumably in an attempt to make up for insufficient nighttime sleep.”

In the paper

“However, in that study, the start time was delayed on Mondays only.”

What the sources say

• ?Not checked — no full text of the sourcecites [78] source

In the paper

“However, the start time study was cross-sectional and other variables such as socioeconomic status may explain the difference in time spent at work.”

What the sources say

• ?Not matched

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

  cites [60]

In the paper

“there is also evidence of a causal relationship between insufficient sleep and depression, as well as mood in general.84,85”

What the sources say

• ?Not checked — no full text of the sourcecites [84] source
• ?Not matched

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

  cites [85]

In the paper

“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”

What the sources say

• ?Not checked — no full text of the sourcecites [86] source

In the paper

“The report also noted that the attendance reporting procedures changed during the course of the study.”

What the sources say

• ?Not matched

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

  cites [81]