CHICAGO (CBS) — A study from the University of Chicago and the University of Pennsylvania has found summer job and mentoring programs for disadvantaged youths in Chicago reduced violent crime arrests by nearly half over a 16-month period.

Dr. Sara Heller, Assistant Professor of Criminology at the University of Pennsylvania, said previous research suggested long-term intensive employment intervention was needed to reduce crime among disadvantaged youths

However, that common wisdom had not been studied vigorously, so Heller worked with the University of Chicago Crime Lab to set up an eight-week program in 2012, dividing 1,600 Chicago teens into three groups: one-third were provided summer jobs and mentors, one-third were given summer jobs, mentors, and counseling, and one-third were left on their own to find jobs.

Heller said those with jobs, or jobs and counseling together, had a 43 percent reduction in violent crime arrests, which continued for 16 months after the eight week program ended.

“Those two versions of the treatment – youths who received jobs, or youths who received jobs with social-emotional learning – had about the same drop in violence,” Heller said.

She said the study shows short-term jobs programs can reduce youth violence, and have a long-term impact.

“Just an eight-week intervention can actually have an enormous impact on violence,” she said. “What the job is doing is teaching kids how to perceive and respond to conflict more constructively. So what we see is a big drop in violent crime, but not in other types of crime; so not in property crime or drug crime.”