Package: irtlink
Title: IRT Linking and Linking Error Estimation Across Time Points and
        Groups
Version: 0.1.0
Authors@R: 
    person("Oskar", "Engels", email = "engels@leibniz-ipn.de",
           role = c("aut", "cre"),
           comment = c(ORCID = "0009-0008-3325-0352"))
Description: Estimation of trends in the mean and standard deviation
    of latent ability distributions across the time points of
    educational assessments, and of ability distribution differences
    across linked groups, for unidimensional item response theory
    (IRT) models (1PL, 2PL, 3PL, partial credit, and generalized
    partial credit). Groups connected through common items, with
    independent or dependent person samples, are calibrated on an
    internal marginal maximum likelihood EM engine, separately,
    concurrently, with fixed item parameters, or with regularized
    calibration. Linking methods include mean-mean and mean-geometric
    mean linking, Haberman linking (Haberman, 2009,
    <doi:10.1002/j.2333-8504.2009.tb02197.x>) with robust Lp loss and
    a pairwise variant (Robitzsch, 2025,
    <doi:10.3390/appliedmath5010007>), and the response function
    methods of Haebara and Stocking-Lord. Under differential item
    functioning (DIF), the linked estimates depend on the selected
    common items, and the package estimates this linking error
    together with the standard error by jackknife and sandwich
    estimators, including bias-corrected variants (Robitzsch, 2024,
    <doi:10.3390/stats7030036>). RMSD and likelihood-ratio DIF
    diagnostics with iterative purification are included.
License: GPL (>= 3)
URL: https://github.com/oskarengels/irtlink
BugReports: https://github.com/oskarengels/irtlink/issues
Encoding: UTF-8
Imports: graphics, grDevices, parallel, Rcpp, stats, utils
LinkingTo: Rcpp
Suggests: knitr, rmarkdown, testthat (>= 3.1.7)
VignetteBuilder: knitr
Config/testthat/edition: 3
NeedsCompilation: yes
Packaged: 2026-10-06 21:45:08 UTC; engels
Author: Oskar Engels [aut, cre] (ORCID:
    <https://orcid.org/0009-0008-3325-0352>)
Maintainer: Oskar Engels <engels@leibniz-ipn.de>
Repository: CRAN
Date/Publication: 2026-10-16 13:30:02 UTC
