Evaluating Measurement Invariance in the IELTS Listening Comprehension Test

Measurement invariance (MI) refers to the degree to which a measurement instrument or scale produces consistent results across different groups or populations. It basically shows whether the same construct is measured in the same way across different groups, such as different cultures, genders, or age groups. If MI is established, it means that scores on the test can be compared meaningfully across different groups. To establish MI mostly confirmatory factor analysis methods are used. In this study, we aim to examine MI using the Rasch model. The responses of 211 EFL learners to the listening section of the IETLS were examined for MI across gender and randomly selected subsamples. The item difficulty measures were compared graphically using the Rasch model. Findings showed that except for a few items, the IELTS listening items exhibit MI. Therefore, score comparisons across gender and other unknown subgroups are valid with the IELTS listening scores.