Distractors & Effectiveness
Although Item Discrimination statistics measure important characteristics about test item effectiveness, they don’t reveal much about the appropriateness of item distractors. By looking at the pattern of responses to distractors, teachers can often determine how to improve the test.
The effectiveness of a multiple-choice question is heavily dependent on its distractors. If two distractors in a four-choice item are implausible, the question becomes, in effect, a true false item. It is, therefore, important for teachers to observe how many students select each distractor and to revise those that draw little or no attention. Use of “all of the above” and “none of the above” is generally discouraged.