Psychometric Properties of the Wisconsin Schizotypy Scales in an Undergraduate Sample: Classical Test Theory, Item Response Theory, and Differential Item Functioning

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Terry A. Ackerman, Professor and Chair (Creator)
Thomas R. Kwapil, Associate Professor (Creator)
Paul Silvia, Professor (Creator)
Beate P. Winterstein (Creator)
The University of North Carolina at Greensboro (UNCG )
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Abstract: The Wisconsin Schizotypy Scales are widely used for assessing schizotypy in nonclinical and clinical samples. However, they were developed using classical test theory (CTT) and have not had their psychometric properties examined with more sophisticated measurement models. The present study employed item response theory (IRT) as well as traditional CTT to examine psychometric properties of four of the schizotypy scales on the item and scale level, using a large sample of undergraduate students (n?=?6,137). In addition, we investigated differential item functioning (DIF) for sex and ethnicity. The analyses revealed many strengths of the four scales, but some items had low discrimination values and many items had high DIF. The results offer useful guidance for applied users and for future development of these scales. The items for the Wisconsin Schizotypy Scales are available from Thomas R. Kwapil.

Additional Information

Language: English
Date: 2011
schizotypy, wisconsin schizotypy scales, classical test theory, item response theory, differential item functioning, psychology

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