Effectiveness of Options in Multiple-choice Items: the case of none of the above

The present study examined the effectiveness of ‘none of the above’ (NOTA) as a test alternative in multiple- choice items.It intended to estimate item fit, item difficulty, itemdiscrimination, guess factor of such a choice and the reliability of the whole test. To this end, the researchersselected five passages of reading section of the Cambridge Key English Test known as KET (2010) and developed a parallel form of that test; test one did not include NOTA, whereas the second test, administered two weeks later, included NOTA. The two tests, 32 items each, were given to 142 high-school third graders. The results, analyzed through 3-parameter logistic model of item response theory (IRT), revealed that multiple-choice questions including the alternative NOTA were easier than their counterparts. In addition, NOTA option did not threaten item fit and item discrimination but increased the guess factor, which, in turn may threaten the reliability and validity of the test.