Similar models were proposed by Cho and Cohen (2010) and Tay et al. (2011) but each has different concepts. Cho and Cohen limits the scope of the model to the one-dimensional Rasch model and use the Bayesian estimate, while Tay et al. limit their scope of their model to the multidimensional 2PL model and use the maximum likelihood (ML) estimation. In this study, however, the scope will be the multidimensional 3PL model using the Bayesian estimate. It can be said that this is a new model which corresponds to the scope of the general unobserved variable model. This model will also be suitable for nested data and two yield results, and it can be used to conduct a survey of LC for each individual. This integration of these models is presented in Venn’s diagram in Figure 1 below: