Table 3

Effect of Family Size on Children’s IQ OLS

No ControlsControls
First ChildSecond ChildThird ChildFourth ChildFirst ChildSecond ChildThird ChildFourth Child
One-child family0.099*
(0.031)		−0.037
(0.028)
Two-child family0.274*
(0.029)		0.222*
(0.031)		0.034
(0.026)		−0.015
(0.028)
Three-child family0.256*
(0.030)		0.236*
(0.031)		0.184*
(0.035)		0.052*
(0.026)		0.037
(0.028)		−0.055
(0.032)
Four-child family0.163*
(0.032)		0.144*
(0.034)		0.093*
(0.039)		0.063
(0.046)		0.051
(0.029)		0.037
(0.031)		−0.028
(0.035)		−0.045
(0.044)
N201,789134,69242,0427,879201,789134,69242,0427,879

  • ↵* indicates statistical significance at the 5 percent level. Standard errors (in parentheses) allow for correlation of errors within family. Each column represents a separate regression. The regressions with controls include indicators for age, test year, mother’s age, mother’s age at first birth, mother’s education, father’s education, father’s IQ, and the log of birth weight of the children studied.

  • Omitted Category is five or more children.