02386nas a2200205   4500008004100000020001400041245008800055210006900143300001400212490000700226520173800233100001401971700001401985700002001999700001702019700001202036700001602048700001502064856010102079       2008                        eng d  a1520-639400aFunctioning and validity of a computerized adaptive test to measure anxiety (A CAT)0 aFunctioning and validity of a computerized adaptive test to meas  aE182-E1940 v253 aBackground: 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.1 aBecker, J1 aFliege, H1 aKocalevent, R D1 aBjorner, J B1 aRose, M1 aWalter, O B1 aKlapp, B F  uhttp://iacat.org/content/functioning-and-validity-computerized-adaptive-test-measure-anxiety-cat