Who gets the kids? Courts aim to decide custody in the child's best interests, but nobody has had the data to test how well those decisions work.
Gordon Dahl (UC San Diego, CEPR), Costas Meghir (Yale, CEPR) and seven co-authors built the data themselves. They collected more than 56,000 Swedish custody rulings, scanning paper files by hand where no digital copy existed, and linked them to records of parents' earnings, prescriptions and children's school tests.
It seems Swedish judges do not agree on how often to award joint custody. Some award it in about 60% of cases; others in about 20%. But that decision makes a huge difference to the lives, and happiness, of both parents and children. They tell Tim Phillips whether joint or sole custody has, on average, better outcomes.
The research behind this episode:
Canessa, Stella, Gordon Dahl, Anna Hasselqvist, Costas Meghir, Susan Niknami, Marten Palme, Helmut Rainer, Olof Rosenqvist, and Pengpeng Xiao. 2026. "Life After Divorce: Effects of Joint Custody on Parents and Children." CEPR Discussion Paper 21780.
To cite this episode:
Phillips, Tim, Gordon Dahl, and Costas Meghir. 2026. "Life after divorce." VoxTalks Economics (podcast).
About the guests
Gordon Dahl is Professor of Economics at the University of California, San Diego, and a Fellow in the Labour Economics programme of the Centre for Economic Policy Research. His research spans the family, public policy and the labour market, including how family income shapes children's achievement, peer effects among co-workers and family members, the effects of incarceration on employment, and how welfare use passes between generations.
Costas Meghir is the Douglas A. Warner III Professor of Economics at Yale University and a CEPR Fellow in the Labour Economics, Development Economics and Public Economics programmes. His research spans labour supply and welfare programmes, marriage markets and how resources are shared within households, informal labour markets, and early childhood development.
Research cited in this episode
The best interests of the child standard. Since the 1970s, most custody law has told judges to decide in the child's best interests rather than weigh the parents' claims. Most countries now read this as keeping both parents involved, which is why joint custody is the default in many jurisdictions. The standard leaves wide discretion to judges, and Meghir says judges get little systematic evidence on what works. Elizabeth Scott and Robert Emery examine why the standard has persisted despite this criticism in "Gender Politics and Child Custody: The Puzzling Persistence of the Best-Interests Standard" (Law and Contemporary Problems, 2014).
The tender years doctrine. Before the mid-19th century, English law treated children as their father's property. The Custody of Infants Act 1839, passed after a campaign by Caroline Norton, let mothers petition for custody of children under seven, and the presumption that young children belong with their mother spread across Europe. Dahl raises it to show how far the legal default has moved in less than two centuries, from father, to mother, to both.
Random assignment of judges. Families who end up with joint custody differ from those who do not, so a simple comparison cannot separate the effect of the arrangement from the effect of the family. In Sweden, custody disputes go to judges at random, and judges differ in how often they award joint custody. Comparing families who drew a lenient judge with families who drew a strict one isolates the effect of the ruling itself. Economists have used the same design to study prison sentences, for example Jeffrey Kling in "Incarceration Length, Employment, and Earnings" (American Economic Review, 2006). The method only measures effects for cases where judges could disagree; it says nothing about cases where every judge would reach the same decision.
Swedish court archives. Custody rulings are public records in Sweden, but no national database holds them. The authors requested files from all 48 district courts and received documents from 45. Digital archives covered cases from about 2010; for earlier years, the team visited court archives and scanned 19,491 paper rulings by hand. Dahl estimates that 80% of the project's time went on collecting data.
Swedish administrative registers. Statistics Sweden registers cover the whole population and record earnings, employment, family links and place of residence. The authors linked these to prescription records, which show who takes antidepressant, anti-anxiety and ADHD medication, and to records of intimate partner violence. This is why the research could follow mothers, fathers and children for years after each ruling.
National tests and school quality. All Swedish pupils sit the same national tests in Swedish and mathematics in grades three, six and nine. The authors use these scores to measure children's achievement, and build a measure of school quality from how much better or worse a school's pupils score than their backgrounds predict. In the paper, joint custody raises test scores by 0.47 of a standard deviation, which Meghir likens to about two extra years of schooling.
More VoxTalks Economics episodes
Helping fathers to acknowledge paternity. Anna Raute on what happens to mothers and children when fathers do not formally recognise their child, and which policies change that.
Love, money and parenting. Fabrizio Zilibotti on what economic research tells us about parenting, and about raising children who thrive.
Related reading on VoxEU.org
The effect of joint custody on marriage and divorce, a VoxEU column by Martin Halla using US state reforms to show that joint custody laws raised marriage rates without a clear effect on divorce.
The effect of parental divorce on children's long-term outcomes, a VoxEU column using Austrian data to estimate how divorce affects children's education, employment and health as adults.
