Does the Quantity–Quality Trade-off Depend on Maternal Education Levels?
This study examines the quantity–quality (QQ) trade-off hypothesis in Japan, focusing on how maternal education influences the allocation of educational resources and the educational outcomes of first-born children. Using data from the Longitudinal Survey of Newborns in the 21st Century (2001 Birth Cohort, 2001–2017) (LSN2001), we estimate a two-stage least squares (2SLS) model that exploits the occurrence of twin births at second parity as an exogenous variation in family size.
Our results indicate that the QQ trade-off varies by maternal education and household income.Among low-income households with highly educated mothers, an increase in sibling size significantly reduces the quality of the first-born child, as measured by the senior high school ranking score (hensachi). This decline is accompanied by a marked decrease in out-of-school educational expenditures. In contrast, no significant effects are observed among households with less-educated mothers or among high-income households.
