Functioning and validity of A Computerized Adaptive Test to measure anxiety (A-CAT)
Article first published online: 31 OCT 2008
© 2008 Wiley-Liss, Inc.
Depression and Anxiety
Volume 25, Issue 12, pages E182–E194, December 2008
How to Cite
Becker, J., Fliege, H., Kocalevent, R.-D., Bjorner, J. B., Rose, M., Walter, O. B. and Klapp, B. F. (2008), Functioning and validity of A Computerized Adaptive Test to measure anxiety (A-CAT). Depress. Anxiety, 25: E182–E194. doi: 10.1002/da.20482
- Issue published online: 2 DEC 2008
- Article first published online: 31 OCT 2008
- Manuscript Accepted: 8 JAN 2008
- Manuscript Revised: 19 OCT 2007
- Manuscript Received: 23 MAY 2007
- Department of Psychosomatics and Psychotherapy, Charité Berlin, Humboldt University Hospital, Germany
- item response theory (IRT);
- computerized adaptive test (CAT);
Background: The aim of this study was to evaluate the Computerized Adaptive Test to measure anxiety (A-CAT), a patient-reported outcome questionnaire that uses computerized adaptive testing to measure anxiety. Methods: The A-CAT builds on an item bank of 50 items that has been built using conventional item analyses and item response theory analyses. The A-CAT was administered on Personal Digital Assistants to n=357 patients diagnosed and treated at the department of Psychosomatic Medicine and Psychotherapy, Charité Berlin, Germany. For validation purposes, two subgroups of patients (n=110 and 125) answered the A-CAT along with established anxiety and depression questionnaires. Results: The A-CAT was fast to complete (on average in 2 min, 38 s) and a precise item response theory based CAT score (reliability>.9) could be estimated after 4–41 items. On average, the CAT displayed 6 items (SD=4.2). Convergent validity of the A-CAT was supported by correlations to existing tools (Hospital Anxiety and Depression Scale-A, Beck Anxiety Inventory, Berliner Stimmungs-Fragebogen A/D, and State Trait Anxiety Inventory: r=.56–.66); discriminant validity between diagnostic groups was higher for the A-CAT than for other anxiety measures. Conclusions: The German A-CAT is an efficient, reliable, and valid tool for assessing anxiety in patients suffering from anxiety disorders and other conditions with significant potential for initial assessment and long-term treatment monitoring. Future research directions are to explore content balancing of the item selection algorithm of the CAT, to norm the tool to a healthy sample, and to develop practical cutoff scores. Depression and Anxiety, 2008. © 2008 Wiley-Liss, Inc.