Functioning and validity of a Computerized Adaptive Test to measure anxiety (A-CAT)

Depress Anxiety. 2008;25(12):E182-94. doi: 10.1002/da.20482.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Anxiety Disorders / diagnosis*
  • Anxiety Disorders / psychology
  • Comorbidity
  • Computers, Handheld*
  • Depressive Disorder / diagnosis
  • Depressive Disorder / psychology
  • Diagnosis, Computer-Assisted*
  • Female
  • Humans
  • Male
  • Mental Disorders / diagnosis
  • Mental Disorders / psychology
  • Middle Aged
  • Models, Statistical
  • Personality Inventory / statistics & numerical data*
  • Psychometrics / statistics & numerical data
  • Psychophysiologic Disorders / diagnosis
  • Psychophysiologic Disorders / psychology
  • Reproducibility of Results
  • Software*
  • Young Adult