This paper illustrates how graphical analyses can enhance
the interpretation and understanding of multidimensional
item response theory (IRT) analyses. Many
unidimensional IRT concepts, such as item response
functions and information functions, can be extended to
multiple dimensions; however, as dimensionality increases,
new problems and issues arise, most notably
how to represent these features within a multidimensional
framework. Examples are provided of several different
graphical representations, including item response
surfaces, information vectors, and centroid plots of conditional
two-dimensional trait distributions. All graphs
are intended to supplement quantitative and substantive
analyses and thereby assist the test practitioner in determining
more precisely such information as the construct
validity of a test, the degree of measurement precision,
and the consistency of interpretation of the number-correct
score scale. Index terms: dimensionality,
graphical analysis, multidimensional item response
theory, test analysis.
Ackerman, Terry. (1996). Graphical representation of multidimensional item response theory analyses. Applied Psychological Measurement, 20, 311-329. doi:10.1177/014662169602000402
Ackerman, Terry A..
Graphical representation of multidimensional item response theory analyses.
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