Large scale international assessments depend on invariance of measurement across countries. An important consideration when observing cross-national differential item functioning (DIF) is whether the DIF actually reflects a source of bias, or might instead be a methodological artifact reflecting item response theory (IRT) model misspecification.…

This study examined the existence of latent classes in TIMSS 2015 data from three countries, Singapure, Turkey and South Africa, were analyzed using Mixture Item Response Theory (MixIRT) models (Rasch, 1PL, 2PL and 3PL) on 18 multiple-choice items in the science subtest. Based on the findings, it was concluded that the data obtained from TIMSS…

In this research, the effect of an item's type and cognitive level on its difficulty index was investigated. The data source of the study consisted of the responses of the 12535 students in the Turkey sample (6079 and 6456 students from eighth and fourth grade respectively) of TIMSS 2015. The responses were a total of 215 items at the eighth-grade…

Item response theory (IRT) has so many advantages than its precedent Classical Test Theory (CTT) such as non-changing item parameters, ability parameter estimations free from the items. However, in order to get these advantages, some assumptions should be met and they are; unidimensionality, normality and local independence. However, it is not…

Background: This paper discusses a framework for analyzing the dependence on mathematical theory in test items, that is, a framework for discussing to what extent knowledge of mathematical theory is helpful for the student in solving the item. The framework can be applied to any test in which some knowledge of mathematical theory may be useful,…

In this study, we investigated gender and minority achievement gaps on 8th-grade science items employing a multilevel item response methodology. Both gaps were wider on physics and earth science items than on biology and chemistry items. Larger gender gaps were found on items with specific topics favoring male students than other items, for…

The least squares distance method (LSDM) was used in a cognitive diagnostic analysis of TIMSS (Trends in International Mathematics and Science Study) items administered to 4,498 8th-grade students from seven geographical regions of Turkey, extending analysis of attributes from content to process and skill attributes. Logit item positions were…

In information-rich environments, schools are often presented with a myriad of data from which decisions need to be made. The use of the information on a classroom level may be facilitated if performance could be described in terms of levels of proficiency or benchmarks. The aim of this article is to explore benchmarks using data from a monitoring…

As the largest international study ever taken in history, the Trend in Mathematics and Science Study (TIMSS) has been held as a benchmark to measure U.S. student performance in the global context. In-depth analyses of the TIMSS project are conducted in this study to examine key issues of the comparative investigation: (1) item flaws in mathematics…