A Brookings Institution policy brief investigated the trade-offs between costs and benefits of pushing back the start times of high school in 2011. It estimated that increased transportation costs would most likely be about $150 per student per year. But more sleep has been shown to lead to higher academic achievement. They found that the added academic benefit of later start times would be equivalent to about two additional months of schooling, which they calculated would add about $17,500 to a student’s earnings over the course of a lifetime. Thus, the benefits outweighed the costs.

This was a reasonably simple analysis, though, and it did not persuade many schools to change. A recent analysis by the RAND Corporation goes much further.

Marco Hafner, Martin Stepanek and Wendy Troxel conducted analyses to determine the economic implication of a universal shift of middle and high school start times to 8:30 a.m. at the earliest. This study was stronger than the Brookings one in a number of ways. It examined each state individually, because moving to 8:30 would be a bigger change for some than for others. It also looked at changes year by year to see how costs and benefits accrued over time. It examined downstream effects, like car accidents, which can affect lifetime productivity. And it considered multiplier effects, as changes to the lives of individual students might affect others over time.

They found that delaying school start times to 8:30 or later would contribute $83 billion to the economy within a decade. The gains were seen through decreased car crash mortality and increased student lifetime earnings.

Since it would take at least a year for any students affected by changes in start times to enter the labor market, there would be no gains in the first year. Costs, however, would accrue immediately. These included about $150 per student per year in transportation costs and $110,000 per school costs in upfront infrastructure upgrades. Even so, by the second year, the benefits outweighed the costs. By 10 years, the benefits were almost double the costs; by 15 years, they were almost triple.

We’d be remiss if we didn’t acknowledge other potential costs not included in this calculation, including parental difficulty in adapting to later school start times. But even in a model where the per-student, per-year cost was increased to $500, which would compensate most parents for delays, and where the upfront per school cost was increased to $330,000, the economic benefits to society would still outweigh the costs in the long run.

Further, it’s important to understand that these benefits may actually be underestimates. The researchers were careful to model only outcomes for which they had empirical data from sleep duration, such as car crashes and academic performance. They didn’t model other real, but quantifiably unknown, benefits, like improvements in rates of depression, suicide and obesity, or the overall effects on health.

Some schools are beginning to take this seriously, but not enough. When it comes to start times, the growing evidence shows that forcing adolescents to get up so early isn’t just a bad health decision; it’s a bad economic one, too.