Each week during the school year, groups of about a dozen middle and high school boys from some of the poorest neighborhoods on Chicago’s south and west sides sit in a circle and talk about their emotions. These students, almost all of whom are African-American or Hispanic, participate in a school program called Becoming A Man, or BAM, put on by the nearly 90-year-old local nonprofit Youth Guidance.

In an activity known as the “Fist Exercise,” students are paired up, one is given a small ball and his partner is given 30 seconds to try to get it from him. The exercise often ends with threats of violence; but in the debriefing afterward, the students are taught to just ask for the ball, as most partners say they are willing to give it up.

The BAM curriculum is not aimed at telling boys how to act, but at improving their meta-cognition — at teaching them to act less automatically. It focuses on learning impulse control and “positive anger expression,” said Jannie Kirby, Youth Guidance’s director of marketing and communications. “Students learn coping skills in anger management so they won’t have violent reactions.” Last year, BAM reached 1,935 boys in 38 schools across the Chicago Public Schools system.

Being in a bad school in a rough neighborhood and from a poor family is not the ideal environment for developing self-control, but programs that focus on behavior and cognition, like this one, might help. New research concludes that participation in the weekly BAM sessions lowered boys’ chances of being arrested for a crime, though it’s unclear if it improved school attendance, as a past study of the program had shown.

These findings are detailed in a recently released working paper, “Thinking, Fast and Slow? Some Field Experiments to Reduce Crime and Dropout in Chicago,” put out by the National Bureau of Economic Research. The title of the paper alludes to the book “Thinking, Fast and Slow” by Daniel Kahneman, which documents the differing psychology of “fast,” or instinctive, thinking and “slow,” deliberate thinking.

The paper presents data from two randomized controlled trials of the BAM program, the second of which is new. (A randomized controlled trial is the ideal field experiment: Eligible subjects are randomly assigned either to receive the treatment — in this case, participation in BAM — or to a control group that does not.)

The paper is not yet peer-reviewed. But the researchers behind it are affiliated with Crime Lab, an innovative collaboration between the University of Chicago and the Chicago Police Department that seeks to use field experiments to improve criminology and policing. And because randomized controlled trials are the gold standard of experimental research, the paper’s findings on BAM carry extra weight.

By comparing the outcomes of those students who participated in BAM with those in a control group who did not, the researchers tried to isolate the effect of the program specifically, without introducing selection bias. They used administrative records on arrests from the Chicago Police Department, as well as school attendance and grades from the schools, to track the students’ outcomes. (Using this data, rather than self-reported survey measures, also lends more credibility to the outcome measurements.)

The researchers then followed up and tested the boys with decision-making games. The youths in the BAM treatment group took 79 percent longer to think before making a decision, backing up the notion that the program’s exercises can help reduce impulsive behavior. As Kirby of Youth Guidance said, “the students are really learning impulse control — how to interpret a situation.”

The first randomized controlled trial on the program was conducted during the 2009-10 academic year and covered 2,740 seventh- to 10th-graders in 18 Chicago schools. About 70 percent of the boys were African-American and 30 percent were Hispanic. Some participated in BAM, while others went to an after-school sports program that incorporated some of BAM’s methods. Some went to both. The control group didn’t participate in either program.

In the year following the program, kids who participated in BAM or the sports program had committed 44 percent fewer violent crimes compared to the youths who didn’t participate in any program. In that study, the educational improvements — better grades, more consistent school attendance — among those participating in a program led the researchers to forecast a 7 percent to 22 percent improvement in graduation rates for the group as a whole.

The second randomized controlled trial, conducted during the 2013-14 school year among 2,064 male ninth- and 10th-graders, reaffirmed the first trial’s finding that BAM specifically was a success at limiting arrests. But the researchers found that school engagement — a host of variables, including days present and GPA — was essentially no different between the students in BAM and those in the control group (made up of students who go to high schools offering regular after-school sports or no programs at all). For boys in BAM, total arrests were 31 percent lower than for the control group.

“It seems like BAM itself is doing something,” said Sara Heller, a professor at the University of Pennsylvania and the lead author of the study.

BAM is not like most school programs. It’s a clinical program — a form of cognitive behavioral therapy. It’s not built for academic remediation, nor does it give youths a temporary job or provide any traditional type of intervention. But that means it could offer a model for a widely applicable, and affordable, program for disadvantaged youths, in Chicago or elsewhere. “It’s not that those other interventions don’t matter, but that BAM might be easier and less costly,” Heller said. Many of the thorniest social problems — like poverty, crime, bad schools, etc. — require enormous resources to tackle. Teaching youths to “slow down and make somewhat more reflective decisions might be a much easier sell,” Heller said.

CORRECTION (June 4, 11:25 a.m.): A previous version of this article incorrectly referred to BAM as an after-school program. It takes place during the school day.