where xij symbolizes the response to the observable variable i by
person j; λi indicates factor loading (i.e., attribute loading) to the
item, which takes three types of the following values: intercept
= 0, main effect = 1, two-way interactions = 2, etc.; αjk symbolizes
latent variable value (i.e., attribute value) for individual j and latent
variable k (k = 2 in equation 1 above); and eij represents the uniqueness
of the individual in observed indicator variables (residuals).