As school bells ring across the nation this fall, kids scurry through breakfast, race to catch buses, struggle through first period. We’ve written about how later school start times can boost performance for teenagers — an area rife with studies as researchers focus on pubescent changes and sleep needs. 

But the younger kids need love too. Later elementary school start times lead to 0.2 percent boosts in grade retention rates for every minute later the school starts, according to a study from Peggy S. Keller at the University of Kentucky. 

With that math, starting half an hour later would mean a 6 percent boost.

And attendance bumped up too. 

“Our findings indicate that early school start times may be just as detrimental for young children as they are for adolescents,” Keller writes.

Keller and her team surveyed 718 schools and found that students in the middle- and upper-class areas fared better. Kids in lower-income areas didn’t see such a boost, but Keller posits that’s because they have a lot more obstacles to overcome, so school start times didn’t have as much impact. 

Part of the issue for many school districts is resources, especially busing. Districts often stagger routes to cut down on busing costs. They can spend less using the same buses for two runs, one for the younger children and one for the older kids, rather then having to bring all kids for all schools in all at once. 

But maybe it’s time to revisit that — push the times back for everyone, or see if schools can double up on transit.