Skip to main content
. Author manuscript; available in PMC: 2021 Oct 14.
Published in final edited form as: Am J Psychiatry. 2015 Apr 23;172(7):630–637. doi: 10.1176/appi.ajp.2015.14070818

Table 2.

Fit indices from model-fitting for twin parents and their offspring on anxiety and neuroticism

Model −2LL AIC df χ2 P
Anxiety
1. Saturated 9582.91 2704.91 3439
2. Full model* 9610.65 2694.65 3458 27.74 (19) .09
3. Direct Transmission Only 9611.16 2693.16 3459 0.51 (1) .47
4. Genetic Transmission Only 9625.15 2707.15 3459 14.5 (1) <.001
Neuroticism
1. Saturated 5717.71 1649.71 2034
2. Full model* 5741.33 1635.33 2053 23.62 (19) .21
3. Direct Transmission Only 5742.06 1634.06 2054 0.73 (1) .39
4. Genetic Transmission Only 5756.44 1648.44 2054 15.12 (1) <.001

Note.

*

The most parsimonious model. The overall model fit is assessed by −2LL, which is minus twice the log likelihood. AIC is the Akaike Information Criterion, another measure of fit. The chi-square (χ2) for model 2 each time is the difference in minus twice the log likelihood (−2LL) between the full genetic and the phenotypic saturated model. In contrast, the chi-square for models 3 and 4 is the difference in −2LL between each model and the full genetic model (model 2).