comparing reliability and item difficulty of multiple-choice and translation questions on a test of grammatical knowledge

multiple-choice questions are commonly employed for testing languageknowledge. however, since in the recently proposed systematic approach toitem writing, using various item formats is desirable and there is very fewresearches on the possibility of using translation items for giving variety toitems on a test. the present study aims at comparing reliability and itemdifficulty of translation and multiple-choice item formats on a test ofgrammatical knowledge. first, the specifications of the tests were composed oftwo sections: one with translation items and the other with multiple-choiceitems, and then reviewed by eight english teachers with some experience inlanguage testing. then, the specifications were revised according to thefeedback. the test for the present study was prepared, and administered to 158english learners with mixed proficiency levels. the data was analyzed usingboth classical test theory and rasch model. the results indicated that both itemformats had good reliability (r translation section = 0.88, r multiple-choicesection = 0.84). also, generally, the items showed good fit in rasch model.furthermore, an independent t-test did not find a significant difference betweentwo formats in terms of item difficulty (t= 1.696, df= 58, p>0.95). therefore,based on the finding of the study, it is suggested that, in a systematic approachto item writing, translation item format can be employed alongside multiple –choice item format for measuring grammatical knowledge.