Many scholars compared various item discrimination indices in real or simulated data. Item discrimination indices, such as item-total correlation, item-rest correlation, and IRT item discrimination parameter, provide information about individual differences among all participants. However, there are tests that aim to select a very limited number…

Research has found that the "a"-stratified item selection strategy (STR) for computerized adaptive tests (CATs) may lead to insufficient use of high a items at later stages of the tests and thus to reduced measurement precision. A refined approach, unequal item selection across strata (USTR), effectively improves test precision over the…

Adult educators in the state of New Jersey have expressed concern about the adequacy of the 1978 General Educational Development (GED) test. Based on these concerns research was conducted in the use and applicability of the current GED test. The project investigated whether the existing GED test was meeting the needs of the large majority of GED…