plink: IRT Separate Calibration Linking Methods

Item response theory based methods are used to compute linking constants and conduct chain linking of unidimensional or multidimensional tests for multiple groups under a common item design. The unidimensional methods include the Mean/Mean, Mean/Sigma, Haebara, and Stocking-Lord methods for dichotomous (1PL, 2PL and 3PL) and/or polytomous (graded response, partial credit/generalized partial credit, nominal, and multiple-choice model) items. The multidimensional methods include the least squares method and extensions of the Haebara and Stocking-Lord method using single or multiple dilation parameters for multidimensional extensions of all the unidimensional dichotomous and polytomous item response models. The package also includes functions for importing item and/or ability parameters from common IRT software, conducting IRT true score and observed score equating, and plotting item response curves/surfaces, vector plots, information plots, and comparison plots for examining parameter drift.

Version: 1.5-1
Depends: R (≥ 3.3.3), methods, lattice
Imports: MASS, statmod
Published: 2017-04-26
Author: Jonathan P. Weeks
Maintainer: Jonathan P. Weeks <weeksjp at>
License: GPL-2 | GPL-3 [expanded from: GPL (≥ 2)]
NeedsCompilation: no
Citation: plink citation info
Materials: NEWS
CRAN checks: plink results


Reference manual: plink.pdf
Vignettes: plink: An R Package for Linking Mixed-Format Tests Using IRT-Based Methods
Package source: plink_1.5-1.tar.gz
Windows binaries: r-devel:, r-release:, r-oldrel:
OS X El Capitan binaries: r-release: plink_1.5-1.tgz
OS X Mavericks binaries: r-oldrel: not available
Old sources: plink archive


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