BIC values for these 3 models were all substantially poorer than for model 2. Since simplification of model 2 did not improve the fit, we then sought to improve fit by including additional common factors. Specifically, in models 8, 9, and 10, respectively, a second genetic, shared, or nonshared environmental common factor was added. Models 8 and 9 were both superior to model 2 in BIC values, with BIC for model 8 appreciably better than for model 2.
