Writing Good Distractors

Multiple Choice Question types are frequently used in exams as an effective measure of a student’s level of knowledge and cognitive skill. In order for multiple choice question types to effectively assess a student’s knowledge, they need to have well written distractors. Below, we will outline some quick tips for writing good distractors. You can computer mark multiple choice questions in Surpass, which will save on valuable time and resources.

What is a Distractor?

A distractor is a wrong answer within a multiple choice, multiple response or either/or style question. In the layout of a multiple choice question, the candidate will see the stem, which is the text containing the question, followed by the correct answer and various distractors in varying orders. Below you can see the typical layout, and how this would look in a question:

             Stem                     >                What is the capital of France? 
             Distractor1           >                Madrid
             Correct Answer   >                Paris 
             Distractor2           >                London  

If none of the distractors are convincing the candidate will be able to select the correct answer regardless of whether of not they know it, simply by recognising that the other answers are too implausible to be correct and eliminating those choices. The examiner would then be prevented from accurately assessing the candidate’s actual knowledge of the topic.

The best types of distractors will need to be sufficiently plausible to pose a degree of challenge to the candidates. Convincing distractors are: common errors or misconceptions, statements that are true, but do not answer the question and content that is wrongly phrased – these can trip up even advanced students.

Writing a Good Distractor  

1) The stem should make sense by itself. A stem that presents a clear problem allows a focus on the learning outcome. A stem that does not do this may leave students struggling to grasp the meaning of the question.  
2) Stems should be phrased positively. Negatively phrased items can confuse students.
3) Alternatives should be the same type or category. A different answer option can provide cues to the student about the correct answer. As the “odd option out” the candidate may realise this must be a correct or incorrect answer.
4) Keep distractors the same length. An answer option  noticeably longer than the others may be a give-away to the candidate as to the right or wrong answer.
5) Avoid inadvertently giving away the correct answer. Any inconsistencies in grammar, formatting and language choice can provide inadvertent clues to the correct answer.  
6) Avoid using “all of the above” or “none of the above” as answer options. The candidate may be able to use these to work out the correct answer, reducing the validity of the exam.  
7) Ensure your answer option(s) are absolutely correct. Any ambiguity, doubt or confusion with either the topic itself or the phrasing of the question will confuse your candidate. Distractors, though plausible, should always be definitely wrong, with no room for debate. 

Note: The purpose of these articles is to provide you with general advice in the fields of assessment and testing. These articles are not intended to replace any regulations or instructions provided by your organisation, but may be used in conjunction with these materials to support the assessment process.

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To learn how to set up a Multiple Choise Question, visit the Multiple Choice section of the Surpass online Help.

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