Despite the prevalence of small family norms, large family size (defined as families with four or more children) is still an important feature of children’s circumstances in many rich countries. Close to one-fifth of 11-13 year olds in the US and UK and one-fourth in Ireland grow up in families of 4 or more children. There is much research on the impact of sibling numbers and birth order on children’s development and later life outcomes. But in the literature on income inequality and poverty, family size attracts little attention. Where it is taken into account, it tends to be measured in ways that understate the prevalence of large family size among children. Here we take up this issue by analyzing household incomes and poverty among 11-13 year olds in large families in the US, the UK and Ireland. The data are taken from the US Current Population Survey 2014, the UK Millennium Cohort Study 2011 and the Growing Up in Ireland Study 2013. We outline the socio-demographic profile of 11-13 year-olds in large families, examine their household income situation and derive both risk and incidence measures of household poverty among them. The data show that while the social profile of large families differs across the three countries, large family size is a significant and under-appreciated risk factor for child poverty in all three. We discuss some policy implications arising from the findings.

Megan Curran has worked as a policy analyst in the field of child advocacy in the United States and is now a PhD candidate in social policy in UCD. Tony Fahey is Professor Emeritus of Social Policy in UCD.