The effect of the conditioning score on the results of
differential item functioning (DIF) analyses was examined.
Most DIF detection procedures match examinees
from two groups of interest according to the examinees’
test score (e.g., number correct) and then summarize the
performance differences across trait levels. DIF has the
potential to occur whenever the conditioning criterion
cannot account for the multidimensional interaction
between items and examinees. Response data were
generated from a two-dimensional item response theory
model for a 30-item test in which items were measuring
uniformly spaced composites of two latent trait parameters, θ₁ and θ₂.
Two different DIF detection methods-
the Mantel-Haenszel and simultaneous item bias
(SIBTEST) detection procedure-were used for three different
sample size conditions. When the DIF procedures
were conditioned on the number-correct score or on a
transformation of θ₁ or θ₂, differential group performance
followed hypothesized patterns. When the conditioning
criterion was a function of both θ₁ and θ₂
(i.e., when the complete latent space was identified),
DIF, as theory would suggest, was eliminated for all
items. Index terms: construct validity, differential
item functioning, item bias, Mantel-Haenszel procedure,
Ackerman, Terry A & Evans, John A. (1994). The influence of conditioning scores in performing DIF analyses. Applied Psychological Measurement, 18, 329-342. doi:10.1177/014662169401800404
Ackerman, Terry A.; Evans, John A..
The influence of conditioning scores in performing DIF analyses.
Retrieved from the University of Minnesota Digital Conservancy,
Content distributed via the University of Minnesota's Digital Conservancy may be subject to additional license and use restrictions applied by the depositor.