Recidivism rates are a growing concern due to the high cost of imprisonment and the high rate of ex-prisoners returning back to prison. One policy-relevant and potentially important determinant of recidivism is the composition of peer inmates. In this paper, we study the role of peer effects within a correctional facility using data on almost 80,000 individuals serving time in Georgia. We exploit randomness in peer-composition over time within prisons to identify effects of peers on recidivism rates. We find no evidence of peer effects for property or drug-related crimes in the general prison population. However, we find strong peer effects when we define peer groups by race and age. Our findings indicate that homophily plays a large part in determining the strength of peer exposure among prisoners in the same facility. These results suggest that prison assignments can be used to reduce recidivism for particular groups of prisoners. (JEL K14, K40).

中文翻译：

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同伴效应和累犯：种族和年龄的作用

由于监禁的高昂成本和前囚犯重返监狱的高比率，累犯率日益受到关注。累犯的一个与政策相关且潜在重要的决定因素是同龄囚犯的构成。在本文中，我们使用佐治亚州近 80,000 名服刑人员的数据研究了惩教设施中同伴效应的作用。我们利用监狱内同伴组成的随机性来确定同伴对累犯率的影响。我们没有发现一般监狱人口中财产或毒品相关犯罪的同伴效应的证据。但是，当我们按种族和年龄定义同龄人群体时，我们会发现强大的同龄人效应。我们的研究结果表明，同质性在确定同一设施中的囚犯之间的同伴接触强度方面起着重要作用。这些结果表明，监狱分配可用于减少特定囚犯群体的累犯。(JEL K14, K40)。