Now, at age 10, Marshaun could calm himself down when upset in the classroom. Occasionally he’d struggle in transitions between classes or at recess when boys jostled against each other, but the staff could de-escalate him with stress balls and fidget spinners. “He’s found things to help him,” Della Flora said.

Another major strategy: a behavioral-management tool known as the PAX game the school introduced. Distributed by the nonprofit PAXIS Institute since 1999, the PAX game aims to teach children to control their impulses by making good behavior fun. The students agree on the type of behaviors they want to see (referred to as “PAX,” the Latin word for peace) and the types they don’t want (“spleems,” an invented word the game’s creators adopted because it’s impossible to say without a smile). These unusual terms help shed any baggage children might have associated with “good choice” or “bad choice” in other environments. Teams of kids compete to win an intangible prize—usually a short, playful activity such as Simon Says—which all students can win as long as their team keeps its spleem count low. Many teachers at Ohio Avenue wear a harmonica on a lanyard around their necks, which they play gently to call kids to attention. Research shows that children with a trauma history may be more sensitive to flashing lights or loud noises, such as the common classroom strategies of getting students’ attention by clapping or flipping the classrooms lights on and off. Harmonicas, blown from high to low, won’t trigger the so-called “fight-or-flight response,” which is a physiological reaction to stress, and which often leads to an escalation of conflict.

Long-term studies of children who experienced the PAX game for just one year, in first grade, showed they were more likely than those who hadn’t to graduate high school; avoid teen pregnancy, drug use, or crime; and achieve better mental and behavioral health. The game also correlates with a reduction of attention-deficit hyperactivity disorder (ADHD) symptoms, such as poor impulse control and distractibility. After a year of the game, the research found, many children had learned to stop such behaviors.

After participating in PAX training a few years ago, Ohio Avenue teachers found themselves sending far fewer children to the room on campus where students go to let out frustration and regain self-control. The number of kids sent to the room for more than an hour, for example, fell from 317 in the 2013–2014 school year to 39 in the 2016–2017 year.

Education policymakers often look for clear narratives in their effort to identify the programs and curricula that will help at-risk children succeed. My time at Ohio Avenue showed me that the approach and mindset of the educators are a key determinant of progress. Those are things that are hard to measure, but ultimately it’s the specific people who shape the outcome of a given policy.

The adults at Ohio Avenue believe so deeply in the power of self-regulation that they’ve embraced it personally. Teachers need tools to self-calm just as much as the children do. McAfee, the fourth-grade teacher, manages her stress by pacing the classroom during lessons; many of Ohio Avenue’s teachers snack on Hot Tamales candy, claiming that the cinnamon helps them calm down. When McAfee and a few other teachers went to an education-leadership summit, she packed so many in her luggage that airport security flagged her bag for a hand search—in an X-ray machine, a carton of Hot Tamales can look like a box of bullets.