D3mirt: Descriptive Three-Dimensional Multidimensional Item Response Theory for R

The D3mirt package for R (R Core Team, 2021) offers functions for analyzing questionnaire items used in psychological research in a three-dimensional latent space.The application is based on descriptive multidimensional item response theory (DMIRT) (Reckase, 1985(Reckase, , 2009;;Reckase & McKinley, 1991), a statistical framework incorporating vector geometry to describe item characteristics.The method is foremost visual, and the latent model can be plotted as an interactive graphical device with the help of a dedicated plot function based on the RGL 3D visualization device system for R (Adler & Murdoch, 2023).Alongside the plot function, the package also includes a model identification function that helps the user identify the DMIRT model and a model estimation function for extracting the necessary vector estimates.New additions to the DMIRT framework introduced in the D3mirt package include studying constructs (explained below) and individual scores plotted in the three-dimensional latent model.