The achievement gap is largely set by age 5: IQ/test scores in standard deviations, by parent income quartile

Age Parent income in lowest quartile Parent income in lowest quartile Parent income in highest quartile Parent income in highest quartile 
0 -0.1206 0.033147
1
2
3
4 -0.28939 0.486972
5 -0.42535 0.53804
6
7 -0.32933 0.485797
8 -0.39463 -0.41495 0.432994 0.361795
9 -0.40094 0.286091
10 -0.44016 0.321102
11 -0.32139 0.360868
12 -0.37427 0.424476
13 -0.32371 0.398653
14 -0.42176 0.41377

Note: IQ scores are available through age 8 and are represented by a solid line. After age 8, math test scores are shown. A 3-year moving average is used for math scores, represented by a dotted line.

Source: Adapted from Council of Economic Advisers (2014)

View the underlying data on epi.org.