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Study published in the Archives of General Psychiatry

A study led by Robert D. Gibbons, Ph.D., was published in the November 2012 issue of Archives of General Psychiatry regarding the development of a computerized adaptive test (CAT) for depression: the CAT-Depression Inventory or “CAT-DI.”
* Please note that Figure 3 in the article referenced above should be replaced with this image.

The paper describes how CAT based on multidimensional item response theory can adaptively select a small targeted set of items for each individual from a much larger bank of test items. The paradigm shift is from a fixed set of items with varying measurement uncertainty to a varying number of items with fixed measurement uncertainty. The net result is a dramatic improvement over traditional mental health measurement. The CAT-DI requires an average of 12 items per patient yet maintains a correlation of r=0.95 with the entire 400 item bank. Using an empirically derived threshold, sensitivity of 0.92 and specificity of 0.88 are obtained for differentiating patients with major depressive disorder (based on systematic DSM-IV interview) versus non-psychiatric controls.