From Yacapaca wiki
- Distractors should be incorrect but plausible. The student should not be able to eliminate a distractor merely because it is blatantly wrong.
- Distractors should be similar to the key in length, complexity and grammatical form. It is easy to find oneself increasing the length and specificity of an answer (relative to distractors) in order to ensure its truthfulness. This, however, becomes an easy-to-spot clue for the testwise student
- Avoid always and never. Choose terms like usually, likely and rarely to prevent students from easily eliminating distractors.
- Use all of the above and none of the above sparingly. All of the above allows students to select the correct response by identifying just two of the options as correct. None of the above does not establish that the student knows the correct answer.
- If possible, ask a colleague with relevant experience of the content to look at your material for possible ambiguities, irrelevancies and other structural problems.