When grading students' quizzes and exams, I find that students are seemingly always changing their answers from the right answer to the wrong answer. In fact, I have cautioned students against changing their answer. Colleagues have made similar observations and some books on test-taking strategies advise against answer-changing. In an effort to find out how pervasive the answer-changing problem was, I collected some data and dug a little deeper into the research. My hypothesis was that students most frequently changed their answers from right to wrong. Have you made similar observations? If yes, then the results of this study may surprise you.