in that parameters rA and rC were fixed to .50 and 1, respectively. Thus, the common effects model allows for quantitative sex differences as well as sex differences in phenotypic variances but not qualitative sex differences. The third model was the scalar model, which allows for sex differences only in phenotypic variances (i.e., no qualitative or quantitative sex differences). In this model, estimates for A, C, and E are constrained to be proportionally equal for males and females. The full sex-limitation model, the common effects model, and the scalar model are hierarchically related (i.e., the scalar and common models are nested within the full model, and the scalar model is nested within the common model) and were compared using Δχ2 and AIC to determine the better fitting model.
