Lessons from the First Statewide Mandate on School Start Times
A new study finds changing school start times has positive effects on sleep, mental health, and achievement
Via a new study from NBER:
We examine the impact of California's Senate Bill 328 (SB 328), the first statewide mandate requiring later school start times for middle and high schools, on adolescent sleep, mental health, and academic outcomes. Using difference-in-differences and event- study designs across five data sources, we find that SB 328 increased the share of students sleeping at least 8 hours per night by 13%, meeting the CDC-recommended minimum for this age group. Average mental health effects are imprecisely estimated, but boys show significant reductions in sadness, hopelessness, and suicidal ideation, and Hispanic students, who experienced the largest sleep-timing shifts, show parallel reductions in difficulty concentrating; together these patterns are consistent with a dose-response relationship between sleep improvement and mental well-being. Math and English scores in grade 8 improved by approximately 0.08-0.10 standard deviations, with the largest gains among Hispanic and economically disadvantaged students. A within-state analysis using teachers' commute arrival times as a proxy for pre-policy school start times corroborates these findings, and shows academic gains accumulating over 2023-2025 alongside a suggestive decline in high school dropout rates.
Ungated working paper here.
Changing school start times may seem like low-hanging fruit, but it’s not simple. Here in Fairfax, we recently spent 16 months debating whether to delay middle school start times. The district hired a contractor which studied the issue and produced model options, conducted focus groups, and wrote up a 233-page report. There seemed to be broad agreement that later school start times would be better, for all the reasons you might expect: better sleep leads to better mental health and better academic outcomes. But the community wasn’t unanimously behind any of the proposed alternatives, there was no solution that was cost-free, and so the School Board eventually dropped the issue.
It is true that there are costs involved with changing school start times, including adapting bus routes and sports schedules and disrupting family routines. But this study provides new evidence that the gains for students are real, and the juice may be worth the squeeze.
Reading List
Education Progress: Voters reject detracking by more than five to one
Sara Mead: How D.C. Became a PreK Leader
Conor Williams: “Teachers do not need to avoid, modify or deviate from the consensus on how best to teach English literacy when working with English learners.”
Nathaniel Hansford: Why Hasn’t the Science of Reading Movement Led to Greater Results?
Wayne D’Orio: Schools with the worst absenteeism problems also have lower student growth
Cafeteria Duty: Too many education preparation programs refuse to teach the science of writing
Project 2029: Every family should be able to choose the child care that’s right for them
Ordinary Abundance: Your modern home is full of things that once inspired awe