Table 3. Results for Mixed Models Predicting Growth in Academic Achievement.
| Predictor | Numerical Operations | Word Reading | ||
| Estimate (se) | p | Estimate (se) | p | |
| Intercept | 26.70(.39) | .0001 | 112.38 (.87) | .0001 |
| Grade | −3.86(.09) | .0001 | −11.06(.23) | .0001 |
| Girl vs. Boy on intercept | −2.31(.56) | .0001 | −1.16(1.25) | .3536 |
| Girl vs. Boy on slope | .36(.13) | .0046 | .85(.32) | .0084 |
| First Grade Working Memory, Intelligence, Attentive Behavior, and RAN RT Predictors of Achievement | ||||
| Intelligence on intercept | .86(.31) | .0063 | 1.90(.71) | .0074 |
| In-class attentive behavior on intercept | 1.64(.34) | .0001 | .71(.78) | .3609 |
| 1st grade central executive on intercept | 1.36(.40) | .0007 | .68(.88) | .4381 |
| 1st grade phonological memory span on intercept | −.02(.37) | .9530 | 1.90(.94) | .0433 |
| 1st grade visuospatial memory span on intercept | −.04(.33) | .8986 | −1.69 (.75) | .0249 |
| 1st grade RAN numeral RT on intercept | −.55(.31) | .0780 | ||
| 1st grade RAN letter RT on intercept | −1.66(.70) | .0183 | ||
| Intelligence on slope | −.11(.07) | .1249 | .40(.18) | .0282 |
| In-class attentive behavior on slope | −.34(.08) | .0001 | .13(.20) | .5004 |
| 1st grade central executive on slope | −.24(.09) | .0069 | .24(.23) | .2959 |
| 1st grade phonological memory span on slope | −.03(.08) | .6798 | .09(.20) | .6707 |
| 1st grade visuospatial memory span on slope | .06(.07) | .4169 | .04(.19) | .8448 |
| 1st grade RAN numeral RT on slope | .00(.07) | .9712 | ||
| 1st grade RAN letter RT on slope | −.49(.17) | .0041 | ||
| Fifth Grade Working Memory and RAN RT Predictors of Fifth Grade Achievement | ||||
| 5th grade central executive on intercept | −.14 (.15) | .3250 | .96(.74) | .1934 |
| 5th grade phonological memory span on intercept | .14 (.15) | .3518 | .41(.75) | .5856 |
| 5th grade visuospatial memory span on intercept | .28 (.13) | .0346 | .81(.65) | .2126 |
| 5th grade RAN numeral RT on intercept | .22 (.12) | .0618 | ||
| 5th grade RAN letter RT on intercept | −1.52(.58) | .0087 | ||
Note: Negative girl vs. boy on intercept estimates mean girls have lower scores in fifth grade. Positive girl vs. boy on slope estimates mean that the sex difference is smaller in earlier grades. RAN = rapid automatized naming; RT = reaction time (sec).