A study provides convincing evidence that the jobs program in Chicago helped reduce violence months after teenagers ended their summer employment. Source: Sara B. Heller: Summer jobs reduce violence among disadvantaged youth. In: Science 5, December 2014, p. 1219-1223. See also: http://www.realclearscience.com/journal_club/2014/12/04/do_jobs_reduce_crime_among_disadvantaged_youth.html