Estimated impacts of IHDP treatment effects on high/low income IQ and achievement gaps.
| Age and outcomes | High-low income gap | IHDP treatment effect for nonlow-income subsample | IHDP treatment* Low-income interaction | Percent Gap closed from universal program | Percent Gap closed from targeted program | |
|---|---|---|---|---|---|---|
| IHDP mean difference | b1 | b2 | b3 | Cb | Cb | |
| IQ at 9 or 12 months | 0.24* (0.14) | 0.01 (0.18) | 0.11 (0.18) | 0.04 (0.25) | 159 (100545) | 999 (182168) |
| IQ at age 2 | 1.35*** (0.18) | 1.09** (0.28) | 0.46* (0.23) | 0.82** (0.30) | 74.8** (22.2) | 117.2*** (20.8) |
| IQ at age 3 | 1.76*** (0.17) | 1.42*** (0.24) | 0.34 (0.21) | 1.28*** (0.31) | 89.4*** (15.2) | 113.4*** (8.4) |
| IQ at age 5 | 1.08*** (0.14) | 0.76** (0.21) | −0.22 (0.22) | 0.77** (0.22) | 101.2* (43.7) | 71.8*** (15.8) |
| IQ at age 8 | 1.03*** (0.15) | 0.77*** (0.17) | −0.08 (0.29) | 0.52 (0.34) | 67.1 (40.9) | 56.7** (15.9) |
| Reading at age 8 or Grade 3 | 1.08*** (0.18) | 0.82*** (0.13) | −0.44 (0.27) | 0.74** (0.23) | 89.7* (37.4) | 36.6 (28.6) |
| Math at age 8 or Grade 3 | 0.96*** (0.19) | 0.76** (0.24) | −0.20 (0.19) | 0.64** (0.22) | 83.6** (30.6) | 56.8** (18.6) |
Notes: “Low income” is defined as having family income < 180 percent of the U.S. poverty line. Estimates in the table come from applying ECLS-B-based weights to IHDP data.