This study investigated the application of item response theory (IRT) to expand the range of ability estimates for gifted (hereinafter referred to as high-achieving) students' performance on an above-level test. Using a sample of fourth- to sixth-grade high-achieving students (N = 1,893), we conducted a study to compare estimates from two…

The accuracy of the results of the national tests in English, mathematics and science taken by 11-year olds in England has been a matter of much debate since their introduction in 1994, with estimates of the proportion of students incorrectly classified varying from 10 to 30%. Using live data from the 2009 and 2010 administration of the national…

Three decision consistency and accuracy (DC/DA) methods, the Livingston and Lewis (LL) method, LEE method, and the Hambleton and Han (HH) method, were evaluated. The purposes of the study were: (1) to evaluate the accuracy and robustness of these methods, especially when their assumptions were not well satisfied, (2) to investigate the "true"…

In many practical settings, essentially the same differential item functioning (DIF) procedures have been in use since the late 1980s. Since then, examinee populations have become more heterogeneous, and tests have included more polytomously scored items. This paper summarizes and classifies new DIF methods and procedures that have appeared since…