Table 2.
Descriptive Statistics for the Child Variables
| N | M(SD) | Reliability | |
|---|---|---|---|
| Executive functions (54 months) | |||
| CPT inhibition errors (reverse-scored) | 1002 | 205.81(21.30) | .65 to .74a |
| CPT sustained attention errors (reverse-scored) | 1002 | 210.87(7.59) | .65 to .74a |
| Delay of gratification (minutes waited) | 961 | 4.48(3.01) | -- |
| Stroop (percent correct) | 838 | 74.66(20.53) | .79b |
| Academic achievement (W-scores) | .80 to .87a | ||
| Elementary school | |||
| 1st grade reading | 1025 | 463.26(20.06) | -- |
| 1st grade math | 1023 | 470.05(15.54) | -- |
| 3rd grade reading | 1008 | 494.58(15.12) | -- |
| 3rd grade math | 1007 | 493.59(12.57) | -- |
| 5th grade reading | 989 | 507.60(14.18) | -- |
| 5th grade math | 989 | 510.56(12.80) | -- |
| High school | |||
| Reading | 883 | 520.35(12.44) | -- |
| Math | 883 | 524.52(16.72) | -- |
| Temperament | |||
| Child difficult temperament (6 months) | 1279 | 3.18(0.40) | .81b |
| Negative affectivity (54 months) | 1060 | 4.30(0.64) | .60 to .76b |
| Surgency/extraversion (54 months) | 1057 | 4.81(0.62) | .70 to .85b |
| Effortful control (54 months) | 1061 | 4.68(0.71) | .74 to .75b |
| General cognitive skills | |||
| Bayley Mental Developmental Index (15 months) | 1180 | 108.58(14.07) | > .80c |
| Picture vocabulary (W-score, 54 months) | 1060 | 459.54(14.09) | ≥ .80a |
Note. When no reliability information is provided, appropriate reliability information was not available for the NICHD SECCYD.
a
Test-retest reliability.
b
Internal consistency reliability (coefficient alpha).
c
Split-half reliability