Population policy, family size and child malnutrition in Vietnam – Testing the trade-off between child quantity and quality from a child nutrition perspective

This paper estimates the quantity-quality (QQ) trade-off of children from a child nutrition perspective, using data on 2000 children born in 2001–2002 from the Young Lives project in Vietnam. Using the sex of the first-born in the family as an instrumental variable for family size, we found that having an additional sibling lowers a 5-year-old Vietnamese child’s height-for-age and weight-for-age Z scores by 0.3 and 0.26 standard deviations (SDs), respectively. This finding is robust to a series of checks, providing strong evidence of the quantity-quality trade-off of children. In more policy-relevant terms, our estimates suggest that the violation of Vietnam’s Two-Child policy (i.e., having more than two children) may have caused reductions in 5-year-old Vietnamese children’s height-for-age and weight-for-age by, respectively, 0.49 and 0.57 SDs.