Should you change an answer when going back over questions in an exam? A now famous, often-quoted research study involved 1,561 University of Illinois students taking exams. The researchers tracked eraser marks on the answer sheets (similar to OREA's scantron cards). Here's the key results and the odds when changing an answer: 51% of changes were from wrong to right; 25% were from right to wrong and 23% were from wrong to wrong. Our advice: Don't do anything in a rush. Think out any change carefully. Want to test the odds and see how well you do when changing answers, you can experiment with Passit. We've got hundreds of practice questions in every guide. (Source: Counterfactual Thinking and the First Instinct Fallacy, Journal of Personality and Social Psychology, 2005, Vol. 88, No. 5, 725–735)