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Tag: multiple-choice tests

multiple-choice tests
Writing good multiple-choice questions

Should students change their answers on multiple-choice questions? Believe it or not, that question has been explored empirically rather at length. Is it an important enough query to merit quantitative analysis? In and of itself, maybe not, but I wonder whether it isn’t related to questions with larger implications: How do you know if you’ve got something right? What makes you doubt an answer, and what questions should you ask when you do? What guidelines should you follow when guessing at the answer?

A current study (Merry et al., 2021) of changing answers on exams in three different STEM courses found that “answer changing is beneficial by approximately a 3-to-1 ratio” (p. 187). That meant a significant improvement in exam scores when these students changed answers. In response to a survey question, 51 percent of the students said that changing answers helped their grades, whereas 27 percent reported that changing hurt their grades. Other research has found students less certain of this benefit. Interestingly, the faculty surveyed in this current study disagreed; just over 6 percent said changing answers helped students, and almost 40 percent reported that it lowered exam scores. Another 34 percent weren’t sure about the effect.

The results of this study are consistent with other research: students change their answers from wrong to right significantly more than they change them from right to wrong. The findings provide useful background for teachers and students, but individual students need to know whether changing answers helps or hurts their scores. I’m not sure many students have made the analysis that would enable them to correctly answer that question. This research uncovered another interesting detail: some students change answers more consistently than other students. Other research found that students change answers more often on difficult questions. The Merry research team wondered whether the motivation to change answers related to the discipline or to a student’s confidence with particular kinds of material. Given how seriously most students take course exams, they should find questions like these of interest.

Furthermore, putting these questions to students during an exam debrief provides the opportunity to raise the larger and more significant questions. What’s the best way to approach a question (any question, really) when you don’t know the answer or think you might know it but aren’t sure? Obviously, if the question is important enough to be on the exam, it contains content students should have learned. Even so, on most exams most students struggle to answer some of the questions. And in life, be it personal or professional, folks are regularly confronted with questions they can’t answer or answer without a lot of confidence.

Intrigue surrounds the confidence issue. Being confident that an answer is right does not guarantee correctness, just as a lack of confidence does not always signal an error. Although researchers have probed the question of why students ultimately decide to change answers (or not), their results are confusing and contradictory. Once again, in all likelihood it depends on the individual student and whether they have thought through the decision to change an answer and arrived at a conclusion that appropriately blends fact and feeling.

On exams, students tend to go with their gut—the answer option that first strikes them as being right, followed by trying not to read too much into the question or overthinking the possibilities. These feeling-based criteria may work, but they should accompany a more reasoned analysis of the question—carefully rereading and rethinking what it’s asking, assessing whether prior knowledge rules out options, and looking for related information in other questions. Most exam environments prevent externally searching for answers. What’s the best approach in any of those situations where answers can’t be acquired or there isn’t time to look up them up?

Asking students to think about when and why they change their answers can lead them to a deeper analysis of knowing when to change answers and how to make reasonable guesses.


Merry, J. W., Elenchin, M. K., & Surma, R. N. (2021). Should students change their answers on multiple choice questions? Advances in Physiology Education, 45(1), 182–190. https://doi.org/10.1152/advan.00090.2020 [open access]