difR - Collection of Methods to Detect Dichotomous and Polytomous
Differential Item Functioning (DIF)
Methods to detect differential item functioning (DIF) in
dichotomous and polytomous items, using both classical and
modern approaches. These include Mantel-Haenszel procedures,
logistic regression (including ordinal models), and
regularization-based methods such as LASSO. Uniform and
non-uniform DIF effects can be detected, and some methods
support multiple focal groups. The package also provides tools
for anchor purification, rest score matching, effect size
estimation, and DIF simulation. See Magis, Beland, Tuerlinckx,
and De Boeck (2010, Behavior Research Methods, 42, 847–862,
<doi:10.3758/BRM.42.3.847>) for a general overview.
