Table 2.
Phenotypically Standardized Covariances.
| Phenotypic Correlation | = | Genetic | + | Shared Environmental | + | Nonshared Environmental | |||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. | 2. | 3. | 4. | 5. | 1. | 2. | 3. | 4. | 5. | 1. | 2. | 3. | 4. | 5. | 1. | 2. | 3. | 4. | 5. | ||||
| 1. Print Knowledge LV | - | - | - | - | |||||||||||||||||||
| 2. Rapid Naming LV | .42 | - | .13 | - | .23 | - | .05 | - | |||||||||||||||
| 3. Phonological Awareness LV | .75 | .36 | - | .32 | .02 | - | .42 | .31 | - | .01 | .03 | - | |||||||||||
| 4. Vocabulary LV | .67 | .35 | .76 | - | .17 | .01 | .21 | - | .48 | .29 | .55 | - | .02 | .05 | .01 | - | |||||||
| 5. Verbal Memory LV | .52 | .27 | .70 | .73 | - | .13 | .10 | .17 | .29 | - | .37 | .14 | .50 | .42 | - | .02 | .03 | .02 | .03 | - | |||
| Word Reading (TOWRE Sight Word Reading Efficiency) | |||||||||||||||||||||||
| Post-1st | .52 | .39 | .44 | .34 | .31 | .29 | .33 | .29 | .17 | .25 | .20 | .02 | .15 | .13 | .04 | .03 | .04 | .00 | .04 | .02 | |||
| Post-4th | .40 | .40 | .39 | .36 | .36 | .20 | .30 | .24 | .19 | .22 | .19 | .06 | .17 | .16 | .12 | .02 | .03 | −.02 | .01 | .02 | |||
| Residual Post-4th | .02 | .16 | .09 | .15 | .19 | −.02 | .07 | .04 | .09 | .05 | .06 | .08 | .08 | .09 | .13 | −.01 | .01 | −.03 | −.03 | .01 | |||
| Reading Comprehension (Woodcock Passage Comprehension) | |||||||||||||||||||||||
| Post-1st | .57 | .38 | .56 | .48 | .41 | .36 | .30 | .42 | .24 | .33 | .19 | .04 | .14 | .17 | .07 | .03 | .03 | .00 | .07 | .02 | |||
| Post-4th | .50 | .34 | .61 | .57 | .55 | .15 | .19 | .28 | .27 | .41 | .30 | .10 | .31 | .27 | .10 | .05 | .05 | .03 | .04 | .04 | |||
| Residual Post-4th | .17 | .12 | .32 | .35 | .38 | −.10 | −.01 | .00 | .15 | .26 | .23 | .09 | .28 | .21 | .08 | .04 | .04 | .04 | −.01 | .04 | |||
| Spelling (WRAT Spelling) | |||||||||||||||||||||||
| Post-1st | .48 | .29 | .46 | .32 | .30 | .30 | .19 | .35 | .23 | .23 | .15 | .07 | .10 | .07 | .05 | .02 | .03 | .01 | .01 | .02 | |||
| Post-4th | .44 | .32 | .46 | .34 | .34 | .32 | .23 | .31 | .18 | .20 | .11 | .06 | .13 | .12 | .10 | .01 | .03 | .02 | .04 | .04 | |||
| Residual Post-4th | .11 | .15 | .17 | .14 | .17 | .13 | .13 | .06 | .01 | .04 | −.01 | .01 | .09 | .09 | .10 | −.01 | .02 | .02 | .04 | .03 | |||
Note: The phenotypic correlations are decomposed into their genetic, shared environmental, and nonshared environmental components. LV = Latent Variable of Pre-reading measures; Residual Post-4th = Post-4th score after controlling for post-1st-grade score.
Correlations/Covariances in bold are significant at p < .05, determined by 95% confidence intervals.