Published by the Foundation for Open Access Statistics Editors-in-chief: Bettina Grün, Torsten Hothorn, Rebecca Killick, Edzer Pebesma, Achim Zeileis    ISSN 1548-7660; CODEN JSSOBK
Authors: David Magis, Bruno Facon
Title: deltaPlotR: An R Package for Differential Item Functioning Analysis with Angoff's Delta Plot
Abstract: Angoff's delta plot is a straightforward and not computationally intensive method to identify differential item functioning (DIF) among dichotomously scored items. This approach was recently improved by proposing an optimal threshold selection and by considering several item purification processes. Moreover, to support practical DIF analyses with the delta plot and these improvements, the R package deltaPlotR was also developed. The purpose of this paper is twofold: to outline the delta plot by describing the original method and its recent improvements in a user-oriented way, and to illustrate the structure and performances of the deltaPlotR package. A real data set about language skill assessment is being analyzed as an illustrative example.

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Paper: deltaPlotR: An R Package for Differential Item Functioning Analysis with Angoff's Delta Plot     Download PDF (Downloads: 4171)
Supplements:
deltaPlotR_1.4.tar.gz: R source package Download (Downloads: 288; 19KB)
v59c01.R: R example code from the paper Download (Downloads: 360; 1006B)
Data-TCALS-1998-2000.txt: Example data in plain text format Download (Downloads: 348; 219KB)
DOI: 10.18637/jss.v059.c01

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Paper: Creative Commons Attribution 3.0 Unported License
Code: GNU General Public License (at least one of version 2 or version 3) or a GPL-compatible license.