Biometric modeling was utilized to evaluate the genetic and environmental moderation of internalizing pathology by marital quality. This type of modeling makes use of twin methodology and structural equation modeling to estimate how much of the variance in a trait (phenotype) is due to additive genetic effects (A), common environmental influences (C), and unique environmental influences (E). The standard univariate “ACE” model assumes that the A, C, and E components are fixed over the entire population from which the sample is drawn. In other words, there is no provision for the association between the genetic and environmental influences on internalizing pathology and any other trait.
