Income-Related Gaps in Early Child Cognitive Development: Why Are They Larger in the United States Than in the United Kingdom, Australia, and Canada?

Abstract

Previous research has documented significantly larger income-related gaps in children's early cognitive development in the United States than in the United Kingdom, Canada, and Australia. In this study, we investigate the extent to which this is a result of a more unequal income distribution in the United States. We show that although incomes are more unequal in the United States than elsewhere, a given difference in real income is associated with larger gaps in child test scores there than in the three other countries. In particular, high-income families in the United States appear to translate the same amount of financial resources into greater cognitive advantages relative to the middle-income group than those in the other countries studied. We compare inequalities in other kinds of family characteristics and show that higher income levels are disproportionately concentrated among families with advantageous demographic characteristics in the United States. Our results underline the fact that the same degree of income inequality can translate into different disparities in child development, depending on the distribution of other family resources.

Keywords: Child development; Cross-national; Parental income; School readiness; Social mobility.

Fig. 1

Within-country gaps in mean early literacy test scores (reference category = Q3). Error bars are 95 % confidence intervals. Q1 to Q5 refer to income groups defined by the quintile boundaries of the U.S. distribution from lowest to highest; that is, Q1 is the group with income less than $27,000, and Q5 is the group with income greater than $96,000. The chart plots the gap in mean standardized test scores between the specified group and the middle Q3 group (families with incomes of $44,000–$65,000 equivalized, in 2011 U.S. dollars). Estimates are calculated from the underlying microdata separately for each country. See Tables 1 and 2 for details of the source samples.

Fig. 2

Within-country gaps in family characteristics (reference category = Q3). Each panel plots the gaps in a different variable. Error bars are 95 % confidence intervals. Q1 to Q5 refer to income groups defined by the quintile boundaries of the U.S. distribution from lowest to highest; that is, Q1 is the group with income less than $27,000 and Q5 is the group with income greater than $96,000. Gaps are the differences between the mean or proportion in the group and the middle (Q3) group (families with incomes of $44,000–$65,000). Estimates are calculated from the underlying microdata separately for each country. See Tables 1 and 2 for details of the source samples.

Fig. 3

Within-country gaps in additional family characteristics (reference category = Q3). Canadian numbers for teenage motherhood suppressed due to small cell sizes. Each panel plots the gaps in a different variable. Error bars are 95 % confidence intervals. Q1 to Q5 refer to income groups defined by the quintile boundaries of the U.S. distribution from lowest to highest; that is, Q1 is the group with income less than $27,000, and Q5 is the group with income greater than $96.000. Gaps are the differences between the mean or proportion in the group and the middle Q3 group. Estimates are calculated from the underlying microdata separately for each country. See Tables 1 and 2 for details of the source samples.