Document Type : Original Research Article
English Department, Islamic Azad University, Mashhad Branch, Mashhad, Iran.
English Department, Farhangian University, Mashhad, Iran.
The purpose of the present study is to compare the psychometric qualities of canonical single-response multiple-choice items with their double-response counterparts. Thirty, two-response four-option grammar items for undergraduate students of English were constructed. A second version of the test was constructed by replacing one of the correct replies with a distracter. The two test forms were analysed by means of the Rasch model. To score double-response items, two scoring procedures, dichotomous and polytomous, were applied and compared. Results showed that dichotomously scored double-response items were significantly harder than their single-response counterparts.Double-response itemshad equal reliability to the single-response items and had a better fit to the Rasch model. Principal component analysis of residuals showed that double-response multiple-choice items are closer to the unidimensionality principle of the Rasch model which can be the result of minimized guessing effect in double-response items.Polytomously scored double-response items, however, were easier than single-response items but substantially more reliable. Findings indicated that polytomous scoring of double-response items without the application of correction for guessing formulas results in the increase of misfitting or unscalable persons.