Royal Kenneth D, Stockdale Myrah R
Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.
College of Pharmacy and Health Sciences, Campbell University, Buies Creek, NC, USA.
J Adv Med Educ Prof. 2017 Apr;5(2):84-89.
Research has asserted MCQ items using three response options (one correct answer with two distractors) is comparable to, and possibly preferable over, traditional MCQ item formats consisting of four response options (e.g., one correct answer with three distractors), or five response options (e.g., one correct answer with four distractors). Some medical educators have also adopted the practice of using 3-option responses on MCQ exams as a response to the difficulty experienced in generating additional plausible distractors. To date, however, little work has explored how 3-option responses might impact validity threats stemming from random guessing strategies, and what impact 3-option responses might have on cut-score determinations, particularly in the context of medical education classroom assessments. The purpose of this work is to further explore these critically important considerations that largely have gone ignored in the medical education literature to this point.
A cumulative binomial distribution formula was used to calculate the probability that an examinee will answer at random a given number of items correctly on any exam (of any length). By way of a demonstration, a variety of scenarios were presented to illustrate how examination length and the number of response options impact examinees' chances of passing a given examination, and how subsequent cut-score decisions may be impacted by these factors.
As a general rule, classroom assessments containing fewer items should utilize traditional 4-option or 5-option responses, whereas assessments of greater length are afforded greater flexibility in potentially utilizing 3-option responses.
More research on items with 3-option responses is needed to better understand what value, if any, 3-option responses truly add to classroom assessments, and in what contexts potential benefits might be discernible.
研究表明，使用三个选项（一个正确答案和两个干扰项）的多项选择题与传统的由四个选项（例如，一个正确答案和三个干扰项）或五个选项（例如，一个正确答案和四个干扰项）组成的多项选择题格式相当，甚至可能更优。一些医学教育工作者也采用了在多项选择题考试中使用三个选项的做法，以应对生成更多合理干扰项时遇到的困难。然而，迄今为止，几乎没有研究探讨三个选项的回答如何影响随机猜测策略带来的效度威胁，以及三个选项的回答可能对分数线的确定产生什么影响，特别是在医学教育课堂评估的背景下。这项工作的目的是进一步探讨这些至关重要的考虑因素，而这些因素在很大程度上在医学教育文献中至今仍被忽视。
使用累积二项分布公式来计算考生在任何考试（任何长度）中随机正确回答给定数量题目的概率。通过示例，展示了各种情景，以说明考试长度和选项数量如何影响考生通过给定考试的机会，以及后续分数线决策可能如何受到这些因素的影响。
一般来说，题目数量较少的课堂评估应采用传统的四个选项或五个选项的回答，而长度较大的评估在潜在使用三个选项的回答方面具有更大的灵活性。
需要对三个选项回答的题目进行更多研究，以更好地理解三个选项的回答真正为课堂评估增加了什么价值（如果有的话）以及在哪些情况下可能会发现潜在的好处。
