KR-21 reliability and its extension (coefficient [alpha]) gives the reliability estimate of test scores under the assumption of tau-equivalent forms. KR-21 reliability gives the reliability estimate for summed scores for dichotomous items when items are randomly sampled from an infinite pool of similar items (randomly parallel forms). The article…

Standard errors computed according to the operational practices of international large-scale assessment studies such as the Programme for International Student Assessment's (PISA) or the Trends in International Mathematics and Science Study (TIMSS) may be biased when cross-national differential item functioning (DIF) and item parameter drift are…

The current simulation study examined the effects of Item Parameter Drift (IPD) occurring in a short scale on parameter estimates in multilevel models where scores from a scale were employed as a time-varying predictor to account for outcome scores. Five factors, including three decisions about IPD, were considered for simulation conditions. It…

One of the best-known methods for setting a benchmark standard on a test is that of Angoff and its modifications. When scored dichotomously, judges estimate the probability that a benchmark student has of answering each item correctly. As in most methods of standard setting, it is assumed implicitly that the unit of the latent scale of the…

The results of an exploratory study into measurement of elementary mathematics ability are presented. The focus is on the abilities involved in solving standard computation problems on the one hand and problems presented in a realistic context on the other. The objectives were to assess to what extent these abilities are shared or distinct, and…

Numerous studies have compared the Angoff standard-setting procedure to other standard-setting methods, but relatively few studies have evaluated the procedure based on internal criteria. This study uses a generalizability theory framework to evaluate the stability of the estimated cut score. To provide a measure of internal consistency, this…