Table 3.
Effect (change in variance accounted for) of twin contact, alcohol/drug group, and the contact × group interaction on child outcomes
| Effect | Child outcome variable |
|||
|---|---|---|---|---|
| Child AD | Child ND | Child CD | Problem index | |
| Alcohol/drug groupa | ΔR2 = .01, p = .01 | ΔR2 = .01, p < .01 | ΔR2 = .01, p = .05 | ΔR2 = .01, p < .01 |
| Twin contactb | ΔR2 = .00, p = .24 | ΔR2 = .00, p = .17 | ΔR2 = .00, p = .18 | ΔR2 = .00, p = .09 |
| Contact × group interactiona | ΔR2 = .00, p = .16 | ΔR2 = .00, p = .42 | ΔR2 = .00, p = .38 | ΔR2 = .00, p = .14 |
| Total R2 of full model | .12 | .06 | .10 | .13 |
ΔR2 indicates the amount that the variance accounted for increased when the specified effect was added to the model The Alcohol Group effect was added to a base model that included the covariates
a
Two terms were added to the model for these effects (see equation and explanation in text)
b
Test of the weighted average of the contact slopes