California’s experiment with pushing back school start times appears to be paying off, according to new research that finds students are sleeping more, struggling less with mental health, and posting better test scores since the state’s later-start law took full effect.
The findings arrive years after a contentious legislative battle over whether Sacramento should dictate school bell schedules or leave such decisions to individual districts and parents.
The debate had simmered for years among educators, researchers and lawmakers. Nearly everyone agreed that children and teens needed more sleep — the disagreement was over whether the state should force the issue through a mandate or trust local communities to figure it out on their own.
Critics warned that shifting start times later would disrupt sports schedules, after-school programs and the routines of working parents who depend on early drop-offs before heading to their jobs. Former Orange County schools superintendent Al Mijares was among those voicing concern, arguing in a 2019 op-ed for CalMatters that a blanket start-time requirement would hit low-income families the hardest, adding another obstacle for students already facing economic disadvantages.
But supporters pointed to a growing body of research backing later start times. A legislative analysis at the time noted that groups including the American Academy of Pediatrics, the American Medical Association and the Centers for Disease Control and Prevention had all flagged the health risks tied to sleep-deprived teenagers attending classes that begin too early. The same analysis noted that pushing back the school day tended to boost both attendance and academic performance.
Lawmakers first approved the change in 2018, only to see it vetoed by then-Gov. Jerry Brown, who argued that a one-size-fits-all state mandate wasn’t the right approach, especially since some schools had already adjusted their schedules voluntarily while others preferred to keep earlier start times. He called it a decision better left to local school boards.
The following governor, Gavin Newsom — a father of four — took a different view. When the same legislation landed on his desk in 2019, he signed it, setting in motion a requirement that middle schools begin no earlier than 8 a.m. and high schools no earlier than 8:30 a.m., starting with the 2022-23 academic year.
Even after the law passed, questions lingered about how the shift would actually play out once schools and families adapted to the new schedules. Now, several years in, a newly released study offers some clarity — and the results appear to support the change.
The stakes are notable given that California continues to trail many other states in student achievement.
A team of four researchers analyzed outcomes from 2022 through 2025 and published their findings in May through the National Bureau of Economic Research. Their conclusion: students statewide are sleeping longer, reporting fewer mental health struggles, and showing measurable gains in math and English performance.
The improvements were seen across demographic groups, the study found, but were particularly pronounced among boys and Latino students.
“Rest and sleep are incredibly important in the function of schools,” said Osea Giuntella, one of the study’s authors, in comments to the Los Angeles Times.
For a policy debate that dragged on for years — and divided lawmakers, educators and parents alike — the new data may finally provide the kind of clear-cut answer that was missing when the fight began.
Original source: CalMatters
