Collection of Methods to Detect Dichotomous, Polytomous, and Continuous Differential Item Functioning (DIF) R package difR version 6.1.0 CRAN Task View: Psychometrics (https://CRAN.R-project.org/view=Psychometrics) Methods to detect differential item functioning (DIF) in dichotomous, polytomous, and continuous 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. Software Depends: R (>= 3.0.0) Imports: mirt, ltm, lme4, deltaPlotR, DescTools, VGAM, glmnet, dplyr, tidyr, tibble, ggplot2 Sebastien Beland <sebastien.beland@umontreal.ca> Comprehensive R Archive Network (CRAN) David Magis [aut] (IQVIA Belux), Sebastien Beland [aut, cre] (Universite de Montreal), Carl F. Falk [aut] (McGill University), Gilles Raiche [aut] (UQAM), Adela Hladka [aut] (Institute of Computer Science of the Czech Academy of Sciences (nee Drabinova)), Josh Gilbert [aut] (Harvard Graduate School of Education-Harvard University) GPL (>= 2) 2025-11-29 application/tgz https://CRAN.R-project.org/package=difR doi:10.32614/CRAN.package.difR