Socioeconomic status

A new academic study finds that California's 2019 law mandating later school start times is producing measurable benefits for students. The law, signed by Governor Gavin Newsom after his predecessor Jerry Brown vetoed a similar bill in 2018, requires middle schools to start no earlier than 8 a.m. and high schools no earlier than 8:30 a.m., a mandate that took effect for the 2022-23 school year.

Researchers examined data from 2022 to 2025 and published their findings in a National Bureau of Economic Research report. They found students are sleeping more, reporting fewer mental health issues, and scoring better on math and English tests. Gains were seen across demographic groups but were especially pronounced among boys and Latino students.

The law had faced years of opposition from parents and education officials concerned about disruptions to extracurricular activities and family schedules, with critics arguing it would burden working families. Supporters cited backing from groups including the American Academy of Pediatrics and the CDC, which linked early start times to sleep deprivation and related harms in adolescents.