Mayor Marty Walsh has often touted Boston's summer youth jobs program as key to reducing violence, which tends to spike during warm months when school is out.

How much does the program actually contribute to keeping the peace on the streets?

The city is halfway through this year's six-week program, which started July 9. More than 3,000 young people, ages 15 to 18, are busy at jobs in parks, office buildings and summer camps across Boston.

Camp Jubilee at the Yawkey Boys and Girls Club in Roxbury employs four teens as part of the program. One recent day at the club, Dellena Bereket, a junior counselor who is 15, was building toy cars with an energetic group of six-year-olds.

“Having this job kind of prepares you for the real world and what it’s like after high school or after college," Bereket said. "It kind of teaches us how to be dependable and collaborate with others.”

Bereket works 25 hours a week, earning $11 per hour through the jobs program. Bereket said the money is good, but she can’t put a price on the real-world skills she's learning.

“When you kind of develop those skills and learn how to take initiative, you’ll ... see past those bad things that maybe other people are partaking in and understand why it’s bad and you know not to participate in,” she said.

Walsh is convinced that summer employment reduces violence among young people during the summer — even though there have been multiple deadly shootings this summer.

“Our summer jobs programs do work,” Walsh said. “It gets kids active and working, and we’ll have more than last year. It definitely helps keeps kids busy, keeps them off the street.”

The city provided more than $5 million for the jobs this year. Walsh asked private employers to hire city youth as well. John Hancock, for example, hired 750 teens as part of its annual MLK Scholars program.

Do the jobs work to reduce crime? Do the young people most in need get these opportunities?

David Siegel, a professor at New England Law Boston, pointed to a study using 2015 data done by Northeastern University professor Alicia Sasser Modestino about the summer jobs program of Action for Boston Community Development, the anti-poverty nonprofit commonly known as ABCD.

"It matched kids, about 1,200 kids who got jobs through ABCD, with 3,000 kids who applied but didn't get them because there aren't enough openings," Siegel said. “What it found was there was a significant reduction in arraignments for violent crime and property crime."

The study also found that this effect lasted longer than the summer.

“That difference between the kids who participated in the program and the kids who didn’t persisted for about 16 or 17 months.” Siegel said. “It wasn’t just a question of kids being occupied doing something like a job, so they couldn’t engage in crime. It was something that happened over the course of their summer jobs. It was something they learned or something they experienced that changed their outlook or their interaction with people.”

But do the kids most prone to getting into trouble land jobs with the city's program? A spokesman was unable to provide a percentage, but some of the summer employees are involved with the legal system, homeless or struggling in school. Some are from single-parent homes.

Andrea Swain, executive director of the Yawkey Boys and Girls Club, said she has seen the benefits of a summer of work during her 30 years helping young people.

“Having a summer job is critical for our young people, especially with the [high] unemployment rate for young black teens,” she said. “It’s imperative that young people have a structured job where they are gaining skills.”

Swain called the city's jobs program a good start, but noted it doesn’t have enough funding to hire every kid who wants a job. She has seen what happens when teens don’t get hired: “We have scores of young people who ended up in the juvenile justice system.”

Clarification: This story has been updated to include the author of the study 2018 study that looks at the crime prevention effects of a youth summer jobs program in Boston.