The link between number of children in the family and children’s educational outcomes

The relationship between number of children in the family and children's human capital has important implications for optimal population policy. We examine the relationship between number of children in the family and children educational outcomes. Using the two percent sample of individual records from Iran Population Census 2011, we constructed a sample of school age children. The empirical model allows for non-linear effects of children quantity on their educational attainment while controlling for other observable household characteristics. Birth order was a key confounding factor which was controlled for. Educational attainment was measured by school progression constructed from comparing actual school grade and expected school grade based on age. Estimation results, using unrestricted ordinary least squares with controlling for confounders including birth order, shows an inverse-U relationship between number of children in the family and educational outcomes; children’s educational performance improves significantly as the number of children increases from one to two. But for families with three or more children, increasing the number of children significantly deteriorates educational outcomes. This corroborates previous findings in the recent literature.