Delayed school start times and adolescent sleep: A systematic review of the experimental evidence
Minges KE, Redeker NS · 2016
grade Creviewindependentreplicated
Sample
6 studies meeting selection criteria (3 pre-post no control, 2 randomized controlled, 1 quasi-experimental)
Population
Adolescent secondary school students
Design
PRISMA systematic review restricted to experimental and quasi-experimental evidence. Only six studies qualified, half of them pre-post with no control group. Predates the START cohort (Widome 2020, James 2023), the Seattle actigraphy study (Dunster 2018), and the large meta-analyses that superseded it.
Key findings
School start times were delayed by 25-60 minutes across the six studies, and total sleep time correspondingly increased by 25 to 77 minutes per weeknight. Some studies also showed reduced daytime sleepiness, depression, caffeine use, tardiness, and trouble staying awake. The authors call for rigorous randomized designs, objective sleep measures, and consistent outcome reporting — a call the field has partially answered on objective measurement and not at all on randomization.
Genetic confound
Not addressed. Half the included studies lack any control group, so secular trends and cohort composition are unaddressed alongside selection.
Effects
| Outcome | Metric | Value | Measure | Timing | Vs | Horizon | Class |
|---|---|---|---|---|---|---|---|
| Total weeknight sleep time (health/behavioural) | range across 6 experimental/quasi-experimental studies | +25 to +77 min for delays of 25-60 min | mixed | post-implementation | unclear | end-of-treatment | health |
| Daytime sleepiness, depression, caffeine use, tardiness | narrative synthesis | reduced in some studies | mixed | post-implementation | unclear | end-of-treatment | health |