What's more, the teens are also more apt to stay out of trouble many months after the work season has ended, according to the researchers.
Researchers found that 25 hours of minimum-wage employment each week during summer break decreased violence among Chicago teens by 43 percent over the course of 16 months, according to findings reported online Dec. 4 in the journal Science.
"A lot of people have this conventional wisdom that nothing stops a bullet like a job, but it's not been clear whether that's true," said study author Sara Heller, an assistant professor of criminology at the University of Pennsylvania. "Now we know these programs are changing youth's future behavior, not just keeping them busy for the summer," she added.
Heller studied more than 1,600 teens in eighth to 12th grade. The teens were from particularly violent and poor Chicago neighborhoods. About half of the teens participated in a public summer jobs program called One Summer Plus, according to the study.
The program puts teens to work in nonprofit and government jobs, such as summer camp counselors, workers in a community garden, or office assistants for an alderman, Heller said in background information. One adult mentor oversees the progress of about 10 students.
Heller then monitored the kids' behavior for 13 months after the jobs program ended. She used administrative and attendance records from Chicago Public Schools and arrest records from the Chicago Police Department.
She found that students enrolled in the program were 43 percent less likely to be arrested for a violent crime -- but not necessarily other types of crimes -- compared to kids not enrolled in the program.
The study only found an association between working in the summer and less violent crime. But the decline in violent crime happened after the summer program ended and persisted for more than a year. So Heller contends that the work did more than simply keep kids off the streets for the summer.
"It might be teaching youths that not everything that happens is an affront to them, not to get quite so angry and not to throw that punch," she said. "It's teaching them to manage their own thoughts and emotions more constructively."
The summer jobs also might instill a sense of pride in earning a paycheck, and an improved ability to work with others, said Ed DeJesus, national director of workforce programs and policy at Youth Advocate Programs, a nonprofit agency that helps troubled kids.
"Work is showing young people that they matter. There are employers out there who value you, want you, are willing to teach you new skills," DeJesus said. "Young people have an awakening, a better outlook for their future. They have hope."
About half of the kids who got a job through One Summer Plus also received counseling to help them understand and manage emotions and behavior that might keep them from succeeding at work.
Interestingly, the kids who received this counseling did not fare any better than the kids who simply went to work, Heller noted. The job itself is what appeared to help keep them out of trouble for as long as a year after it had ended, according to the study.
Federally funded summer jobs programs are available in many major U.S. cities. "A lot of cities already do this," Heller said.
These cities could do better by expanding their summer jobs programs and making sure that the work goes to kids who are at risk of violence, she said.
Heller also noted that the adult mentors assigned to kids in Chicago's jobs program could play a key role, since they help the teens manage problems like transportation, job-appropriate clothing and other barriers to employment.
"That's something other cities should experiment with, the role of that mentor," she said. "We need some more work to figure out what works and for whom, but these jobs programs are something that's much easier to implement than other violence-reduction programs we've seen."
For more information on teen violence, visit the National Institutes of Health.