The purpose of this study is to determine the purpose, scope, research model, data collection tool, data analysis method and sample size of the studies on bilingualism. According to the general screening model, the documents collected were analyzed. In the first step, in order to determine the focus and scope, the objectives of the sample studies…

This dissertation proposes two modified cognitive diagnostic models (CDMs), the deterministic, inputs, noisy, "and" gate with hierarchy (DINA-H) model and the deterministic, inputs, noisy, "or" gate with hierarchy (DINO-H) model. Both models incorporate the hierarchical structures of the cognitive skills in the model estimation…