Table 4. Parameter Estimates.
| Models | |||||
|---|---|---|---|---|---|
| Estimates/Model Fit Statistics | Fully Unconstrained | Constrain ACE Ages 13-30a | Constrain ACE Ages 13-41b | Fully Constrainedc | |
| Parameter Est: | |||||
| 10-12 years | |||||
| A | .00 (.00-.44) |
.00 (.00-.44) |
.00 (.00-.44) |
.54 (.38-.59) |
|
| C | .58 (.12-.73) |
.58 (.12-.73) |
.58 (.12-.73) |
.00 (.00-.15) |
|
| E | .42 (.27-.64) |
.42 (.27-.64) |
.42 (.27-.64) |
.46 (.41-.51) |
|
| 13-15 years | |||||
| A | .52 (.30-.61) |
.49 (.30-.48) |
.54 (.40-.59) |
-- | |
| C | .00 (.00-.18) |
.03 (.00-.20) |
.00 (.00-.13) |
-- | |
| E | .48 (.39-.59) |
.48 (.42-.55) |
.46 (.41-.51) |
-- | |
| 16-19 years | |||||
| A | .62 (.09-.75) |
-- | -- | -- | |
| C | .00 (.00-.44) |
-- | -- | -- | |
| E | .38 (.25-.57) |
-- | -- | -- | |
| 20-25 years | |||||
| A | .51 (.28-.60) |
-- | -- | -- | |
| C | .00 (.00-.20) |
-- | -- | -- | |
| E | .49 (.40-.60) |
-- | -- | -- | |
| 26-30 years | |||||
| A | .50 (.00-.70) |
-- | -- | -- | |
| C | .07 (.00-.55) |
-- | -- | -- | |
| E | .43 (.30-.61) |
-- | -- | -- | |
| 31-41 years | |||||
| A | .28 (.00-.65) |
.28 (.00-.65) |
-- | -- | |
| C | .27 (.00-.60) |
.27 (.00-.60) |
-- | -- | |
| E | .45 (.35-.57) |
.45 (.35-.57) |
-- | -- | |
| Model Fit: | |||||
| -2lnL (df) | 7732.09 (2217) | 7756.79 (2225) | 7749.98 (2229) | 7762.35 (2232) | |
| Δχ2 (df) | -- | 33.70 (8) | 17.89 (12) | 30.26 (15) | |
| p | -- | <.001 | .12 | .01 | |
| AIC | 3298.09 | 3306.79 | 3291.98 | 3298.35 | |
Note. A = additive genetic effects; C = shared environmental effects; E = nonshared environmental effects; -2lnL = -2 times the log likelihood; Δχ2 = the difference in -2lnL values between the fully unconstrained and the nested constraint models; AIC = Akaike's Information Criteria. Twins from complete and incomplete pairs were included in the analysis. The best-fitting model is noted in bolded text.
Parameter estimates are constrained to be identical from ages 13-31; thus, these estimates are only listed for the age 13-15 group.
Parameter estimates are constrained to be identical from ages 13-41; thus, these estimates are only listed for the age 13-15 group.
Parameter estimates are constrained to be identical across all ages; thus, these estimates are only listed for the age 10-12 group.