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. Author manuscript; available in PMC: 2015 May 1.
Published in final edited form as: Dev Psychol. 2012 Nov 26;50(5):1362–1376. doi: 10.1037/a0030725

Figure 3.

Figure 3

Full biometrical moderation model with Conscientiousness moderating the genetic and environmental influences on Alcohol Use Problems (model is shown for only one member of the twin pair). A signifies influences due to additive genetics, C refers to shared (common) environmental influences, and E refers to non-shared (unique) environmental variance. Ac, Cc, and Ec represent the common variance shared between Conscientiousness and Alcohol, while Au, Cu, and Eu represent any residual variance in Alcohol after accounting for Conscientiousness. Moderation of Alcohol by Conscientiousness is represented by the product of a coefficient that indexes the direction and magnitude of moderation (e.g., βXc) multiplied by the level of the moderator. The total phenotypic variance in Alcohol can be calculated by squaring and summing all of the paths leading to it: P2= (aC+βXacM)2 + (aU+βXauM) 2 + (cC+βXccM)2 + (cU+βXcuM)2 + (eC+βXecM) 2 + (eU+βXeuM) 2.