01431nas a2200133   4500008004100000020001400041245008500055210006900140300001200209490000700221520094900228100001701177856010301194       2010                        eng d  a2190-050700aDesigning item pools to optimize the functioning of a computerized adaptive test0 aDesigning item pools to optimize the functioning of a computeriz  a127-1410 v523 aComputerized adaptive testing (CAT) is a testing procedure that can result in improved precision for a specified test length or reduced test length with no loss of precision. However, these attractive psychometric features of CATs are only achieved if appropriate test items are available for administration. This set of test items is commonly called an “item pool.” This paper discusses the optimal characteristics for an item pool that will lead to the desired properties for a CAT. Then, a procedure is described for designing the statistical characteristics of the item parameters for an optimal item pool within an item response theory framework. Because true optimality is impractical, methods for achieving practical approximations to optimality are described. The results of this approach are shown for an operational testing program including comparisons to the results from the item pool currently used in that testing program.Key1 aReckase, M D  uhttp://mail.iacat.org/content/designing-item-pools-optimize-functioning-computerized-adaptive-test