plink-package {plink}R Documentation

IRT Separate Calibration Linking Methods

Description

This package uses item response theory methods to compute linking constants and conduct chain linking of tests for multiple groups under a nonequivalent groups common item design. It allows for mean/mean, mean/sigma, Haebara, and Stocking-Lord calibrations of dichotomous (1PL, 2PL, and 3PL) and/or polytomous (graded response, partial credit/generalized partial credit, nominal, and multiple-choice model) common items.

Details

Running the separate calibration is typically a two-step process. The first step is to format the item parameters for processing with plink. Parameters should be formatted as a single irt.pars object with multiple groups, a set of irt.pars objects, or a set of sep.pars object. Once in this format, response probabilities can be computed using drm, gpcm, grm, mcm, or nrm or linking constants can be computed using plink.

The functions as.irt.pars, sep.pars, and combine.pars can be used to create the irt.pars and sep.pars objects. The function summary can be used to summarize item parameters (including descriptive statistics) and linking constants, and plot can be used to create item/category characteristic curves.

Author(s)

Jonathan P. Weeks weeksjp@gmail.com


[Package plink version 0.1-1 Index]