Table 4.
Fit statistics from the models of variance components allowing for gene-environment interaction and correlation
| Model | −2*LL | df | χ2 | Δdf | p | AIC |
|---|---|---|---|---|---|---|
| Age 24 AAB as a function of age 24 educational attainment | ||||||
| All parameters free | 3675.4 | 2154 | --- | --- | --- | 3709.4 |
| Fix all moderation paths | 3687.4 | 2160 | 12.0 | 6 | ns | 3709.4 |
| Age 17 AAB as a function of age 17 GPA | ||||||
| All parameters free | 6172.2 | 3599 | --- | --- | --- | 6206.2 |
| Fix common A, C, & E | 6172.5 | 3602 | .3 | 3 | ns | 6200.5 |
| Fix common A, C, & E, and unique A moderation paths | 6177.9 | 3603 | 5.4 | 1 | ns | 6203.9 |
| Fix common A, C, & E, and unique C moderation paths* | 6172.5 | 3603 | .0 | 1 | .020 | 6198.5 |
| Fix common A, C, & E, and unique E moderation paths | 6208.1 | 3603 | 35.6 | 1 | <.001 | 6234.1 |
| Fix common A, C, & E, and unique C & A moderation paths | 6191.9 | 3604 | 19.4 | 2 | <.001 | 6215.9 |
| Fix common A, C, & E, and unique C & E moderation paths | 6208.1 | 3604 | 35.6 | 2 | <.001 | 6232.1 |
| Fix common A, C, & E, and unique A & E moderation paths | 6234.3 | 3604 | 61.8 | 2 | <.001 | 6258.3 |
| Fix all moderation paths | 6299.4 | 3605 | 126.9 | 3 | <.001 | 6321.4 |
Note: A refers to genetic influences, C to shared environmental influences, and E to nonshared environmental influences. There are possible common and unique moderation paths for each of A, C, and E. Best-fitting models are indicated by *. Fixed moderation paths were constrained to 0, which means that those sources of influence were present but did not vary across the levels of the moderators. AIC is Akaike Information Criterion.