(CBT) can efficiently improve individuals’ misbehavior and criminal outcomes (Blattman et al., 2017; Heller et al., 2017),<sup>3</sup> this paper provides experimental evidence designed to measure the effect of a CBT-inspired ASP to enhance impulse control and conflict management on participants’ violent behaviors and academic outcomes in the context of a developing and highly violent country. Second, we also study differences in the ASP’s impacts by students’ initial propensity for violence. Third, by exploiting the quasi-exogenous exposure to treated participants, we study spillover effects on misbehavior and academic attainment of at-risk children who were not enrolled in the ASP. Finally, by collecting neurophysiological recordings, we estimate the ASP’s impact on participant emotional regulation, which in our context is a proxy of motivation or disposition to act, and stress.<sup>4</sup> We discuss how this effect may be a mechanism of how the ASP modifies behaviors and academic performance. To our knowledge, this is the first experimental assessment of a CBT-inspired ASP’s impact from a country with these characteristics and on these categories of outcomes.

The intervention was performed in five public schools located in violent communities in El Salvador. This context is key for two reasons. First, El Salvador is a lower-middle-income country defined as a victim of an “epidemic of violence” since 2009 (WHO, 2011) and categorized as one of the top five deadliest places for adolescent boys in 2015 (UNICEF, 2017).<sup>5</sup> Second, El Salvador’s high violence levels and homicide rates have significantly affected its educational system in the last years. The country has witnessed a 13% reduction in its education enrollment rate (MINED, 2015),<sup>6</sup> with approximately 18% of students reporting they dropped out of school due to delinquency.<sup>7</sup> Also, in the past five years, more children and adolescents there have been victims of homicide than in the previous two decades (EPCD 2014).<sup>8</sup> The ASP we study in this article consists of clubs implemented after school hours within school

> 3For example, CBT is a therapeutic approach used to treat harmful beliefs and behaviors by making people aware of these patterns and trying to disrupt them through a “learning by doing process” (Blattman et al., 2017).

> 4As we explain below, “emotional regulation” is defined as a mixture of cognitive and emotional processes that affect a disposition to act (Salzman and Fusi, 2010). It involves consciously affecting one’s own emotional and physical responses to given stimuli.

> 5Between 2009 and 2012, the country’s average homicide rate was 69 murders per 100,000 inhabitants (PNUD, 2013). Over half of those killed during this time period were 15 to 34 years old; approximately 80% of the victims were male; 70% were executed using firearms; and nearly 40% of the murders took place in public spaces (FUNDAUNGO, 2013). In 2015, El Salvador was the country with the highest murder rate in the world: 103 killings per 100,000 inhabitants. As a reference, the worldwide homicide rate is 6.2 murders per 100,000 inhabitants (PNUD, 2013).

> 6In 2013, primary and secondary net enrollment rates were 93.4% and 61.6% respectively, after a relevant drop in 2015, when primary and secondary net enrollment rates were only 86.2% and 37.9% respectively (MINED, 2015).

> 7This may be a lower bound because 28.6% of students abandoned school due to change of address, which since 2010 has been highly correlated with gang threats according to testimonies elicited by local newspapers (LPG, 2016).

> 8From 2005 to 2013, approximately 6,300 youth were homicide victims. In 2013, 458 adolescents were charged with extortion and 321 with aggravated homicide (CSJ, 2014), which are crimes mainly related to gangs (PNC, 2014).

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