What is the most significant weakness of binary-choice assessments such as true-false questions?

The most significant weakness of binary-choice assessments, such as true-false questions, lies in the fact that students have an equal likelihood of guessing the correct answer. With only two possible answers, there is a 50% chance that a student can arrive at the correct answer purely by chance, even if they lack understanding of the material. This characteristic can lead to inaccuracies in measuring a student's actual knowledge or comprehension of the content.

Moreover, this potential for guessing doesn’t provide a reliable assessment of student understanding; it can inflate scores and misrepresent a student’s grasp of the subject matter. Therefore, while binary-choice assessments can be useful for evaluating basic recall or factual knowledge, this inherent possibility of guessing undermines their effectiveness in reflecting true student proficiency or mastery of concepts.