Resolved the misalignment issue of standard errors in the output
of the est_irt() function when
fix.a.1pl = TRUE is specified and the items are calibrated
using the 1PLM.
Added a new function, grdif(), to perform
differential item functioning (DIF) analysis across multiple groups.
This function calculates three generalized IRT residual DIF (GRDIF)
statistics. For more information about the function and its usage,
please refer to the accompanying documentation.
Fixed several typos in the manual documentation
Initial release on CRAN
The irtQ package is a successor of the
irtplay package which was retracted from R CRAN due to the
intellectual property (IP) violation. All issues of the IP violation
have been clearly resolved in the irtQ package.
Most of the functions the irtQ package are identical
in appearance and functionality to those of irtplay package
except a few functions (e.g., shape_df(),
est_score()). However, the computing speed of several
functions (e.g., est_irt(), est_score(),
lwrc()) in the irtQ package are faster than
the previous ones in the irtplay package. Read the
documentation carefully prior to using the functions.