Should students change their answers on multiple choice questions?

Multiple choice exams are ubiquitous, but advice on test-taking strategies varies and is not always well informed by research. This study evaluated the question of whether students benefit or are harmed when they change their initial answers on multiple choice questions in the context of physiology and biology courses. Previously marked examinations were reviewed for eraser marks that indicated answer changes, and the impact of these changes on exam grades was tabulated.