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…

Variable-length computerized adaptive testing (CAT) can provide examinees with tailored test lengths. With the fixed standard error of measurement ("SEM") termination rule, variable-length CAT can achieve predetermined measurement precision by using relatively shorter tests compared to fixed-length CAT. To explore the application of…

The purpose of this book is to make it possible for measurement specialists to solve practical testing problems through the use of item response theory (IRT). The topics, organization, and presentation are those used in a 4-week seminar held each summer for the past several years. The material is organized to facilitate understanding; all related…