Sibship size and children’s cognitive and non-cognitive outcomes: evidence from China

This paper examines how sibship size affects children’s cognitive and non-cognitive skills using data from the China Family Panel Studies (CFPS). To obtain the causal effect of sibship size on child development, we use first-born twins as an instrumental variable for sibship size and find that a larger sibship size significantly reduces children’s literacy and maths test scores, but alleviates depressive symptoms. When examining the potential channels behind the estimated effects, we find that having more siblings reduces educational expenditure on children and lowers their educational expectations, while prompting children to seek emotional support from their siblings, which suggests that sibship size weakens children’s cognitive skills mainly through resource dilution and alleviates children’s depressive symptoms largely through sibling interaction. Furthermore, we find that the effect of sibship size on child development varies by hukou status, household economic status, school quality, and child gender.