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A bill being debated in the state Legislature to prohibit middle and high schools from starting earlier than 8:30 a.m. received a boost Wednesday with the release of an economic study showing that a later school start time could result in a $1.1 billion increase to the state’s economy after two years and $24.8 billion in 20 years.

State Sen. Anthony Portantino, D-La Cañada Flintridge, who is sponsoring the legislation to push back school start times, said the RAND Corporation and RAND Europe report provides the economic data to support the bill, which will be heard Friday by the Assembly Appropriations Committee.

“This is staggering,” Portantino said of the study. “It completely and totally makes an economic argument on the heels of 20 years of scientific research that shows it’s healthier for kids.”

The report is the first in-depth economic analysis of data for 47 states based on pushing back school start times. The researchers found that after a decade of later school start times the economy would receive an $83 billion boost nationwide.

The economic benefits are based on better academic performance and a reduction in car crashes caused by sleep-deprived teens.

“The benefit-cost projections of this study suggest that delaying school start times is a cost-effective, population-level strategy that could have a significant impact on public health and the U.S. economy,” the authors wrote.

• Read more: No more school daze? California weighs making middle & high schools start later so students can sleep in

Costs associated with moving back school start times are transportation costs from changes in school bus schedules and rescheduling after school activities. A fiscal analysis by the Appropriations Committee of Portantino’s bill (SB 328) found “significant local costs for school districts” for transportation and changes in collective bargaining agreements. It also cited potential costs “likely in the low millions” for additional staff time for supervision before school starts.

The RAND study found that after five years, for every $1 spent, the return would be between $1.70 and $2.11. California would likely break even after two years.

“The impact to the budget has been an overblown, red herring argument,” Portantino said. “The statistics show that there really is no significant increase in costs.”

School districts that support the bill include Pasadena Unified, South Pasadena Unified, Manhattan Beach Unified, and Fresno Unified. The La Cañada Unified School Board voted this spring to push back the start time at La Cañada High to 8:30 a.m. starting this year.

LA Unified has piloted a later school start time this year at Los Angeles Academy Middle School, San Fernando Middle School, Stephen White Middle School, New Middle School Pathway, and Metropolitan Continuation High School.

About one-fifth of California’s schools start later than 8:30 a.m.

Charter schools would be exempt from the later start mandate.

The authors note the study takes a conservative approach and the benefits are likely an underestimation.

“Throughout the cost-benefit projections, we have taken a conservative approach when establishing the economic gains,” Marco Hafner, a senior economist at RAND Europe, said in a news release. “We have not included other effects from insufficient sleep, such as higher suicide rates, increased obesity and mental health issues, which are all difficult to quantify precisely. Therefore, it is likely that the reported economic and health benefits from delaying school start times could be even higher across many U.S. states.”

Because of the delay in sleep-wake cycles in adolescents, which means teens naturally fall asleep later and wake up later, medical and pediatric organizations like the American Academy of Pediatrics recommend middle and high schools should start school later. Due in part to earlier school start times, 60 percent of middle and high schoolers sleep less than the recommended eight to 10 hours on weeknights.

Portantino said a later school start time has resulted in happier mornings at his home since his own teenage daughter has started school later and now wakes up on her own. He said he’s heard similar stories from his constituents. He said one mom told him there’s “smiles in the morning instead of grumpy faces.”

“Everything the research said would happen, happened immediately,” he said.

If the bill passes the Appropriations Committee on Friday it will head to the Assembly floor. The Senate has already approved the bill.