Arshya Keyvanfar - Islamic Azad University, North Tehran Branch and University of Tehran
Sepideh Tahami - Islamic Azad University, North Tehran Branch, Faculty of Foreign Languages, TEFL Department

Cognitive diagnostic assessment (CDA) is a careful diagnostic assessment approach with the purpose of providingdiagnostic analysis by determining cognitive skills required to correctly answer an item in a tested domain. This studyhas investigated the necessary sub-skills in answering the reading module of the IELTS exam. The think-aloud verbalprotocols gathered from Iranian EFL learners while answering IELTS reading comprehension tests were analyzed. TheQ- matrix was constructed before the test was administered to a second group of IELTS candidates. Four predictionswere investigated and the aim was finding any relationship between CDA and the IELTS reading score, the ItemFacility as well as Item Discrimination, and the examinees’ self-assessment of their own reading comprehension ability.The findings revealed that the more sub-skills needed for answering an item, the larger number of candidates managedto answer it correctly. It was found that the more sub-skills an item needed, the higher its item facility was; in contrast,the fewer the sub-skills an item needed, the easier it could discriminate masters from non-masters. Finally, it wasproved that Iranian IELTS candidates did not have an accurate picture of their own reading skills. To conclude, theimportant potential application of these findings could be beneficial for test designers, teachers, and students.

Cognitive Diagnostic Assessment, Fusion Model, Item Facility, Item Discrimination, skill profiles, verbal protocol