Item response theory (IRT) is a core analysis for test developers and researchers working with questionnaires, surveys, psychological measures of mood and cognition, and educators interested in academic achievement. It serves to provide information about both items and individuals in a comprehensive, connected framework. Basic IRT models make an assumption that the set of items measures a single common construct, such as intelligence. However, in reality, many constructs are multidimensional in nature, meaning that they consist of what can be thought of as several subconstructs. Standard IRT techniques are not able to accurately model such item responses because of their assumption of unidimensionality. For this reason, researchers working with multidimensional constructs need an alternative modeling paradigm, which comes in the form of multidimensional IRT (MIRT). ...