Crimes committed by at-risk Chicago students dropped in half, and high-school graduations rose sharply in an innovative education program called Becoming a Man that is capturing national attention and could become one antidote to the city’s persistent bloodshed, according to a newly published study.

BAM focuses on adolescent and teenage boys on the city’s violent South and West sides. They’re deemed at risk to fail and are offered a chance to skip a class to participate in a program that tries to teach them alternatives to having “automatic” negative responses to stressful situations.

In one exercise, a leader asks one boy to hold a ball and another student to take it away. Typically, the second boy physically wrests away the ball. Then the leader asks the boy who held the ball what he would have done if he were asked politely to give it up. Usually, he responds that he would because it’s just a ball.

The study by researchers from the University of Chicago Crime Lab, Northwestern University, Harvard University and the University of Pennsylvania examined how such BAM lessons affected thousands of students from 2009-2010 and 2013-2015.

The results are being presented Monday in Baltimore at the Obama administration’s fifth annual National Summit on Preventing Youth Violence and are being published in the Quarterly Journal of Economics.

The randomized study compared about 4,800 BAM students with peers in regular school programs. Violent-crime arrests fell 50 percent, and arrests for all types of crime fell 35 percent among the BAM students — although those declines were not “persistent” after they cycled out of the BAM program.

Nevertheless, high-school graduation rates rose 19 percent among the same BAM kids.

Roseanna Ander, executive director of the U. of C. Crime Lab, said she wasn’t surprised that the lower arrest rates didn’t last beyond the BAM program because of the challenges the students face on the street. But she said a high-school diploma will make them much less likely to become victims of crime or perpetrators when they become adults.

The study results provide hope in cities like Chicago which have been suffering huge spikes in murders and shootings recently, Ander said. It counters skepticism in the academic world about the impact of social programs on adolescents and teenagers, she said.

A similar program in the Cook County juvenile detention center reduced readmission rates 21 percent, the study concluded.

The researchers found evidence that the program worked by helping the students “slow down” and reflect on whether their “automatic thoughts and behaviors are well-suited to the situation they are in.”

“The rate of return to investing in helping youth make better judgments and decisions in high-stakes moments seems promising,” the researchers wrote.

Youth Guidance is the nonprofit Chicago agency that developed BAM more than a decade ago.

“We meet youth where they are, physically within schools and emotionally with nurturing adult relationships, to help form positive youth identities that greatly improve their chances of school and life success,” said Michelle Adler Morrison, CEO of Youth Guidance, the nonprofit Chicago agency that developed BAM more than a decade ago.

Jannie Kirby, a spokeswoman for BAM, pointed to one student, Chris, whose father was absent in his life and whose stepfather is incarcerated. He witnessed violence firsthand in Englewood, was shot at several times and had lackluster grades until he entered BAM. But he recently graduated from Hyde Park Academy.

“I had no father figure, really,” he said in an interview. “I really had no one to look up to.”

He plans to attend Northern Illinois University and study sports medicine.

BAM currently serves more than 2,700 young men in 50 Chicago schools and is seeking to expand.

Mayor Rahm Emanuel has supported the program, and in a statement, said the study confirms “what we already know about the remarkable effects of the Becoming a Man program, and also affirm that an investment in our children’s futures is the most important investment we can make in Chicago’s future.”