Differential Item Functioning in While-Listening Performance Tests: The Case of the International English Language Testing System (IELTS) Listening Module

This article investigates a version of the International English Language Testing System (IELTS) listening test for evidence of differential item functioning (DIF) based on gender, nationality, age, and degree of previous exposure to the test. Overall, the listening construct was found to be underrepresented, which is probably an important cause of the observed lack of significant correlation between awarded scores on while-listening performance (WLP) tests and subsequent academic performance. Some short answer items were biased toward higher-ability subgroups, likely due to those test takers' higher ability to apply what they had understood. Finally, some multiple-choice questions (MCQs) with few options likely encouraged attempts at lucky guesses, particularly among low-ability people who had received training in test-taking strategies. Implications for listening assessment and language education are discussed.