Social capital is widely cited as benefiting children’s school performance, but close inspection of existing research yields inconsistent findings. Focusing on intergenerational closure among parents of children in the same school, this article draws from a field experiment to test the effects of social capital on children’s achievement in reading and mathematics. When children were in first grade, their schools were randomly assigned to an after-school family-based intervention that boosts social capital. A total of 52 schools in Phoenix, Arizona, and San Antonio, Texas, containing over 3,000 first graders, participated in the study, with half the schools in each city assigned to the treatment group and half serving as no-treatment controls. Two years later, no differences in third-grade achievement were evident between children who had been in treatment schools versus control schools. By contrast, nonexperimental analyses of survey-based measures of social capital suggest positive effects on achievement, indicating that naïve estimates based on survey measures may be upwardly biased by unobserved conditions that lead to both stronger ties among parents and higher test scores. This article adds to a growing literature that raises doubts about the effects of this type of social capital for achievement outcomes among young children.

社会资本被广泛认为有益于儿童的学校表现，但对现有研究的仔细检查会得出不一致的结果。本文着眼于同校儿童家长的代际封闭，通过实地实验来检验社会资本对儿童阅读和数学成绩的影响。当孩子们上一年级时，他们的学校被随机分配到一项以家庭为基础的课后干预措施，以提高社会资本。亚利桑那州凤凰城和德克萨斯州圣安东尼奥市共有 52 所学校参与了这项研究，其中包括 3,000 多名一年级学生，每个城市的一半学校被分配到治疗组，另一半作为无治疗对照组。两年后，在治疗学校和对照学校就读的儿童在三年级成绩方面没有明显差异。相比之下，基于调查的社会资本措施的非实验分析表明对成就有积极影响，表明基于调查措施的幼稚估计可能会因未观察到的情况而向上偏倚，导致父母之间的联系更紧密，考试成绩更高。这篇文章补充了越来越多的文献，这些文献对这种类型的社会资本对幼儿成就成果的影响提出了质疑。表明基于调查措施的幼稚估计可能会因未观察到的情况而产生向上偏差，导致父母之间的联系更紧密，考试成绩也更高。这篇文章补充了越来越多的文献，这些文献对这种类型的社会资本对幼儿成就成果的影响提出了质疑。表明基于调查措施的幼稚估计可能会因未观察到的情况而产生向上偏差，导致父母之间的联系更紧密，考试成绩也更高。这篇文章补充了越来越多的文献，这些文献对这种类型的社会资本对幼儿成就成果的影响提出了质疑。