Senior Researcher, National Institute of Population and Social Security Research Empirical Social Security Research
Visiting Professor, Graduate School of Economics and Management, Tohoku University

Professor, Graduate School of Economics and Management, Tohoku University

Professor, Faculty of Economics, Keio University

Research Fellow, Australian Institute of Family Studies

Using data from the Longitudinal Survey of Newborns in the 21st Century, we examine the effect of sibship size on high school standardized rank score in Japan. Using twin births as a control variable, the causal effect of sibling size on high school standardized hensachi scores is not found in the pooled sample across Japan, but emerges only when we divide the sample into urban and rural areas. We also find that when the number of children increases, parents and children in urban areas try to mitigate the adverse effects on hensachi by increasing the inputs of study time and conversations with parents. On the other hand, rural parents and their children reinforce the adverse effects by reducing their inputs.