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# CITATION.cff file created with {cffr} R package
# See also: https://docs.ropensci.org/cffr/
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cff-version: 1.2.0
message: 'To cite package "irtlink" in publications use:'
type: software
license: GPL-3.0-or-later
title: 'irtlink: IRT Linking and Linking Error Estimation Across Time Points and Groups'
version: 0.1.0
abstract: 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, <https://doi.org/10.1002/j.2333-8504.2009.tb02197.x>) with robust Lp loss
  and a pairwise variant (Robitzsch, 2025, <https://doi.org/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, <https://doi.org/10.3390/stats7030036>). RMSD and likelihood-ratio DIF diagnostics
  with iterative purification are included.
authors:
- family-names: Engels
  given-names: Oskar
  email: engels@leibniz-ipn.de
  orcid: https://orcid.org/0009-0008-3325-0352
preferred-citation:
  type: manual
  title: 'irtlink: IRT Linking and Linking Error Estimation Across Time Points and
    Groups'
  authors:
  - family-names: Engels
    given-names: Oskar
    email: engels@leibniz-ipn.de
    orcid: https://orcid.org/0009-0008-3325-0352
  year: '2026'
  notes: R package version 0.1.0
  url: https://CRAN.R-project.org/package=irtlink
repository: https://cran.r-universe.dev
repository-code: https://github.com/oskarengels/irtlink
commit: 3c2dd8ba15a445c78dea7033f2949629d7e42db9
url: https://github.com/oskarengels/irtlink
date-released: '2026-10-16'
contact:
- family-names: Engels
  given-names: Oskar
  email: engels@leibniz-ipn.de
  orcid: https://orcid.org/0009-0008-3325-0352