The aim of this study was to examine log linear modelling (LLM) compared with logistic regression (LR) and Mantel-Haenszel (MH) test for detecting Differential Item Functioning (DIF) in a mastery test. The three methods were chosen because they have similar components. The results showed fairly high matching percentages together with high…

Many examination agencies, policy makers, media houses, and the public at large make high-stakes decisions based on test scores. Unfortunately, in some cases educational tests are not statistically equated to account for test differences over time, which leads to inappropriate interpretations of students' performance. In this study we illustrate…

This study uses PISA cycle 3 field trial data to investigate the relationships between gender differential item functioning (DIF) across countries and test languages for science items and their formats and the four other dimensions defined in PISA framework: focus, context, competency, and scientific knowledge. The data used were collected from 60…

Differential item functioning (DIF) analysis is a statistical technique used for ensuring the equity and fairness of educational assessments. This study formulates a new DIF analysis method using the information similarity index (ISI). ISI compares item information functions when data fits the Rasch model. Through simulations and an international…

Comparisons of human characteristics across different language groups and cultures become more important in today's educational assessment practices as evidenced by the increasing interest in international comparative studies. Within this context, the fairness of the results across different language and cultural groups draws the attention of…

In this study, we examined the presence of differential item functioning (DIF) among groups of students who were tested in their native language or in a different language when participating in the 1999 Trends in International Mathematics and Science Study. Data from 18,837 examinees from three countries (Singapore, United States, and Iran) were…

This study investigates the effect of reporting the unadjusted raw scores in a high-stakes language exam when raters differ significantly in severity and self-selected questions differ significantly in difficulty. More sophisticated models, introducing meaningful facets and parameters, are successively used to investigate the characteristics of…

When a test is adapted from a source language (SL) into a target language (TL), the two forms are usually not psychometrically equivalent. If linking between test forms is necessary, those items that have had their psychometric characteristics altered by the translation (differential item functioning [DIF] items) should be eliminated from the…

There has been considerable research regarding the extent to which psychometric sound assessments sometimes yield individual score estimates that are inconsistent with the response patterns of the individual. It has been suggested that individual response patterns may differ from expectations for a number of reasons, including subject motivation,…

Test validity is predicated on there being a lack of bias in tasks, items, or test content. It is well-known that factors such as test candidates' mother tongue, life experiences, and socialization practices of the wider community may serve to inject subtle interactions between individuals' background and the test content. When the gender of the…