irt is an R package that contains many helpful functions for psychometric analysis.
See the quick start guide.
The current release is available on CRAN, you can install it via:
install.packages("irt")
Install the latest development version from Github:
if (!requireNamespace("devtools")) install.packages("devtools")
devtools::install_github("egonulates/irt")
Note that the development version can contain untested features.
Please use the Issues tab for bug reports, questions, or feature requests.