The aim of
the study is to examine differential item functioning (DIF) detection methods—the
simultaneous item bias test (SIBTEST), Item Response Theory likelihood ratio (IRT-LR),
Lord chi square (χ2), and Raju area measures—based on ability estimates when
purifying items with DIF from the test, considering conditions of ratio of the
items with DIF, effect size of DIF, and type of DIF. This study is a simulation
study and 50 replications were conducted for each condition. In order to
compare DIF detection methods, error (RMSD) and coefficient of concordance
(Pearson’s correlation coefficient) were calculated according to estimated and
initial abilities for the reference group. As a result of the study, the lowest
error and the highest concordance were seen in the case of 10% uniform DIF in
the test and the method of IRT-LR, considering all other conditions. Moreover,
for the method of SIBTEST and IRT-LR in all conditions, it was found that the
error obtained by purifying items with C level DIF is lower than the error
obtained by purifying items with both B and C level DIF. Similarly, for the
method of SIBTEST and IRT-LR in all conditions, it was seen that the
concordance coefficient found by purifying C level DIF is higher than the
coefficient by purifying items with both B and C level DIF.
Primary Language | English |
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Journal Section | Articles |
Authors | |
Publication Date | June 28, 2019 |
Acceptance Date | May 26, 2019 |
Published in Issue | Year 2019 |