The optimal number of options for multiple-choice questions on high-stakes tests: application of a revised index for detecting nonfunctional distractors

Research suggests that the three-option format is optimal for multiple choice questions (MCQs). This conclusion is supported by numerous studies showing that most distractors (i.e., incorrect answers) are selected by so few examinees that they are essentially nonfunctional. However, nearly all studies have defined a distractor as nonfunctional if it is selected by fewer than 5% of examinees. A limitation of this definition is that the proportion...