Research

Divorce reshapes family life, yet little is known about one of its most consequential features: the allocation of child custody. We study the impact of joint versus sole custody on both parents and children using rich administrative data from Sweden linked to over 25 years of newly-collected court custody rulings. To address selection concerns, we exploit random assignment of custody disputes to judges who differ sharply in their propensity to grant joint custody. For fathers, joint custody substantially raises earnings and improves mental health, consistent with sustained paternal involvement enhancing labor market attachment and psychological well-being. In contrast, there are no measurable labor market or mental health effects for mothers. Turning to children, joint custody increases standardized test scores and school quality without affecting mental health outcomes. Joint custody increases fathers' chances of remarriage, keeps separated parents in closer geographic proximity, and has no effect on intimate partner violence allegations against either partner. These findings inform longstanding debates over the role of child custody in shaping post-divorce family life.

Academic inequality between migrants and natives is often attributed to family dynamics that are difficult to observe. Siblings provide a way to study them: I estimate the effect of having a high-achieving sibling on the educational outcomes of children in migrant and native families. Using exogenous variation in sibling achievement from Sweden’s school-entry cutoff in a Regression Discontinuity Design, I show that second-generation migrant girls face a unique disadvantage. A high-achieving brother lowers their grades, while a high-achieving sister has a small positive influence. Spillover effects are negligible for boys and native children regardless of sibling gender. Heterogeneity analysis suggests that traditional cultural norms contributes to this disadvantage, and parental labor market integration substantially attenuates it.