Public policy and the effect of sibship size on educational achievement: A comparative study of 20 countries

Using international data on educational achievement among 15-year-olds in 20 OECD countries, I compare the effect of sibship size on reading literacy and link the cross-national variation in the sibship-size effect to differences in national contexts of public policies for families and children. Comparisons highlight significant cross-national variation in the level of public policies, even among countries ordinarily thought to belong to the same welfare regime. Deviating from previous literature that focused on overall differences across welfare regimes, I explore the way in which specific public policy variables, rather than categorical regimes, mediate the relationship between sibship size and educational achievement. The results of two-level hierarchical linear models show that countries with stronger public support for childcare, universal child benefits, larger public expenditures on education and family, show a much less negative effect of growing up in large families. Moreover, these policy variables explain a large part of the better performance of social democratic countries in reducing the negative effect of sibship size.