California Forum

California students need more sleep. But later start times probably won’t help

In a couple of years, classes at many high schools and middle schools in California will start later. As a consequence, academic achievement at these schools will rise. The students will be healthier. They will be more alert and awake. Car accidents and mental health problems among them will be reduced.

Only one of those statements – the first – is a fact. The rest are theories, not without evidence, but based on an incomplete and often conflicting body of research. Maybe this will work and we’ll see some real improvements with one quick, if extremely complicated, fix. But I’m not betting on it. And if it doesn’t work as advertised, the state will have caused enormous disruption and damaged schools for little to nothing.

It looks as though legislators and Gov. Gavin Newsom got excited about the feel-good rhetoric and neglected to read the legislative staff analysis that accompanied Senate Bill 328. Under the new law, which takes effect with the 2022-23 school year, middle schools will not be allowed to start before 8 a.m. and high schools not before 8:30 a.m. Rural schools are exempted, as well as “zero period,” which is an extra class period early in the morning used for elective courses.


This much we know about the good intentions behind the law: American teenagers are indeed sleep deprived. And though cell phones and other devices play a role in that, this sleep issue was true before blue-light screens. There’s simply a change in circadian rhythms in the adolescent brain that make teens feel sleepy later and thus want to wake up later. Sleep-deprived kids are more likely to be late to school, to learn less, drive cars less safely, fall into depression and so forth.

More winks equal better-off kids, so the obvious answer is to start school later. That’s why the American Academy of Pediatricians supports later school starts for adolescents.

The problem is that when theory meets reality the obvious becomes murky. The history of education reform is littered with seemingly obvious ideas that never worked out.

Of course, we don’t really know what the reality of later school times looks like. It hasn’t been tried in enough places for long enough to get a solid grasp of how well the idea works. It could open the eyes of the state’s teenagers, but the analysts who looked at the state of research had less glowing things to say.

The science isn’t especially promising on this key question: Does a later school day mean that teenagers get more sleep, or do they simply go to bed later? The legislative analysis discusses one study that found students got an extra 11 minutes of sleep for each half-hour that school was delayed. That’s a mere 22 minutes of sleep for each hour that school starts later. Another study seems to verify that, finding that students got about 20 more minutes of sleep. In one study, students slept more the first year but then switched to later bedtimes the second year.

Karin Klein
Karin Klein

A recent study in Washington state found that students earned higher grades and had better attendance and fewer tardy days after a switch to a later school start. But the study looked at only one year of change. And other studies haven’t always found the same success.

Meanwhile, parents who have to get to work on time might need to drop their kids off at school early anyway. That’s probably going to mean schools opening part of their buildings early, at least during bad weather, and providing supervision. Schools will need to juggle bus schedules and probably use more electricity and gas as after-school extracurricular activities continue into nighttime. This all involves expenditures for which the state isn’t reimbursing them, meaning less money for the classroom.

Even if later school starts are helpful, we can expect very limited impact in California. According to the legislative analysis, nearly three-fourths of middle and high schools in the state start at 8 a.m. or later. That means no difference for those middle schoolers, and only an additional half hour at the very best for high schoolers. Add that to the parents who need to drop the kids off earlier anyway – which is expected to especially affect low-income and working-class families – and exemptions for rural schools and zero periods, even at best, it’s a precious few students who will gain sleep.

Los Angeles has been running a pilot program with later start times at a few schools. After two years, according to an article in the Los Angeles Times, they’ve seen no conclusive evidence of benefits. But again, it’s only two years. As the legislative analysis notes, every study on the subject contains the caveat that more study is needed.

The benefits of later school times have not been established. And yet we’re turning the biggest school system in the nation into a giant guinea pig in an experiment that could involve significant downsides. Maybe there will be benefits to this mostly incremental shift in school times, but we ought to know that before we mess with the schedules of millions of people.

Karin Klein is a freelance journalist in Orange County who has covered education, science and food policy. She can be contacted at Follow her on Twitter @kklein100.
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