Complex multiple-choice questions are inequitable for low-income and domestic students (and difficult for everyone)

High-stakes exams play a large role in determining an introductory physics student's final grade. These exams have been shown to be inequitable, often to the detriment of students identifying with groups historically marginalized in physics. Given that exams are made up of individual questions, it is plausible that certain types of questions may be contributing to the observed equity gaps. In this paper, we examine whether that is the case for one type of forced-choice question, the complex multiple-choice (CMC) question. In a CMC question, students must select an answer choice that includes all correct responses and no incorrect responses from a list. To conduct our study, we used four years of data from Problem Roulette, an online program at our university that allows students to prepare for exams with actual questions from previous years' exams in a not-for-credit format. We categorized the 951 Physics II (Electricity and Magnetism) questions in the database as CMC or non-CMC. We found that students performed 8.0 percentage points worse on CMC questions than they did on non-CMC questions. In addition, we found differential impacts for low income students and domestic students relative to medium and high income students and international students. Regression models supported these descriptive findings. The results suggest that complex multiple-choice questions may be contributing to the equity gaps observed on physics exams. Considering, however, that CMC questions are more difficult for everyone, future research should examine the source of this difficulty and whether that source is functionally related to learning and assessment. For example, our data does not support using CMC questions instead of non-CMC as a way to differentiate top-performing students from everyone else.

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