Document Type : Original Research Article
English Department, Islamic Azad University, Mashhad Branch, Mashhad, Iran.
In the current study, the validity of C-Test is investigated using the construct identification approach. Based on construct identification approach, the factors which are deemed to affect item difficulty in C-Test items were identified. To this aim, 11 factors were selected to enter into Linear Logistic Testing Model (LLTM) analysis to reconstruct C-Test item difficulties using the difficulty of the underlying factors. The 11 factors explained only 12% of the variance in item difficulties. Findings revealed that content words, inflections, and the frequency of the mutilated words had the greatest impact on C-Test item difficulty.