lsirm12pl: An R package for latent space item response modeling

The latent space item response model (LSIRM; Jeon et al., 2021) allows us to show interactions between respondents and items in item response data by embedding both items and respondents in a shared and unobserved metric space. The R package lsirm12pl implements Bayesian estimation of the LSIRM and its extensions for different response types, base model specifications, and missing data. Further, the lsirm12pl offers methods to improve model utilization and interpretation, such as clustering of item positions in an estimated interaction map. lsirm12pl also provides convenient summary and plotting options to assess and process estimated results. In this paper, we give an overview of the methodological basis of LSIRM and describe the LSIRM extensions considered in the package. We then present the utilization of the package lsirm12pl with real data examples that are contained in the package.