irtQ - Unidimensional Item Response Theory Modeling
Fit unidimensional item response theory (IRT) models to
test data, which includes both dichotomous and polytomous
items, calibrate pretest item parameters, estimate examinees'
abilities, and examine the IRT model-data fit on item-level in
different ways as well as provide useful functions related to
IRT analyses such as IRT model-data fit evaluation and
differential item functioning analysis. The bring.flexmirt()
and write.flexmirt() functions were written by modifying the
read.flexmirt() function (Pritikin & Falk (2022)
<doi:10.1177/0146621620929431>). The bring.bilog() and
bring.parscale() functions were written by modifying the
read.bilog() and read.parscale() functions, respectively (Weeks
(2010) <doi:10.18637/jss.v035.i12>). The bisection() function
was written by modifying the bisection() function (Howard
(2017, ISBN:9780367657918)). The code of the inverse test
characteristic curve scoring in the est_score() function was
written by modifying the irt.eq.tse() function (González (2014)
<doi:10.18637/jss.v059.i07>). In est_score() function, the code
of weighted likelihood estimation method was written by
referring to the Pi(), Ji(), and Ii() functions of the catR
package (Magis & Barrada (2017) <doi:10.18637/jss.v076.c01>).
