To address the lack of attention to construct shift in IRT vertical scaling, a bifactor model is proposed to estimate the common dimension for all grades and the grade-specific dimensions. The bifactor model estimation accuracy is evaluated through a simulation study with manipulated factors of...

Although the design of Multistage testing (MST) has received increasing attention, previous studies mostly focused on comparison of the psychometric properties of MST with CAT and paper-and-pencil (P&P) test. Few studies have systematically examined the number of items in the routing test, the...

The primary purpose of this study is to investigate the impact of the local item dependence (LID) of testlet items on the performance of the multistage tests (MST) that make pass/fail decisions. In this study, LID is simulated in testlet items. Testlet items are those that physically share the...

A Monte Carlo simulation study investigated the effect of scoring format, item parameterization, threshold configuration, and prior ability distribution on the accuracy of ability estimation given various IRT models. Item response data on 30 items from 1,000 examinees was simulated using known...

The problem with which this study is concerned is articulating all possible CT3 and KR21 reliability measures for every case of a 5x5 binary matrix (32,996,500 possible matrices). The study has three purposes. The first purpose is to calculate CT3 for every matrix and compare the results to the...