[RETRACTED ARTICLE] irtplay: An R Package for Unidimensional Item Response Theory Modeling Hwanggyu Lim, Craig S. Wells The article and accompanying software package have been retracted by the authors, and hence removed from the journal, because the software violated the copyright of a proprietary software and the intellectual property of a third party. Journal of Statistical Software August 2022 https://doi.org/10.18637/jss.v103.i12