The effect of using "none of the above" option on psychometric properties of multiple choice questions

The purpose of the research is to investigate using "none of the above" (NOTA) option on psychometric properties of multiple choice tests (MC): Item difficulty, item discrimination, and test reliability. Using two test forms symmetrical in content, consisted of (25) MC items with four options, the first form items had real options, the second form was built by replacing the key option in (13) items, and one of the distractors in the (12) items left, by NOTA option. These forms were applied on (240) individuals. The research results indicate that the existence of the NOTA option makes the test items more difficult, while it presence does not affect item discrimination nor test reliability.