Government-sponsored summer jobs programs for youth are widespread and politically popular, costing billions of dollars since the federal government started funding them in 1964. Yet although employment programs for adults and out-of-school youth have been the focus of an enormous amount of study, there is basically no rigorous evidence on the effects of providing in-school youth with summer jobs. This panel will present four well-identified papers on the effects of summer jobs based on large-scale programs in two of the nation's largest cities: Chicago and New York City. The two papers on New York City’s Summer Youth Employment Program take advantage of the fact that program slots have been allocated via random lottery for many years. They focus on two different outcome measures: Schwartz et al. study the program’s effects on schooling outcomes, and Gelber et al. focus on employment outcomes. Both papers match applicants from the lotteries to administrative data, generating high-quality evidence of the effects of this on-going, at-scale summer jobs program. The two papers on Chicago’s One Summer Plus (OSP) program are from two different randomized controlled trials in the summers of 2012 and 2013. Because OSP was designed primarily as a violence-prevention program, both papers focus on measuring youth violence and delinquency, but also match youth to schooling and (eventually) employment data. In addition to measuring the overall effects of the program, the Heller paper tests whether providing a social-emotional learning curriculum in addition to a summer job and adult job mentor improves outcomes. The Davis and Heller paper presents a follow-up study replicating the earlier results and testing a key aspect of treatment heterogeneity: whether the program effects differ for youth who are more deeply involved in the criminal justice system versus those who simply live in high-violence neighborhoods. (Note that if the review panel prefers only 3 papers, these two papers could be presented together as one.) There is a disturbing disconnect between the prevalence of youth summer jobs programs and the amount of evidence available on their effects; other than the papers in this panel, existing research consists of almost exclusively observational studies. The papers here represent an enormous advance in our understanding of these common but little-studied programs. Together, they provide the first convincing look at the effects of summer jobs, spanning different outcomes, program models, populations, and settings. The findings are highly relevant to the current national policy conversation’s focus on employment and training, as well as youth violence and outcomes for disadvantaged youth.