If good measurement depends in part on the estimation of accurate item characteristics, it is essential that test developers become aware of discrepancies that may exist on the item parameters before and after item review. The purpose of this study was to examine the answer changing patterns of students while taking paper-and-pencil multiple choice exams, and to examine how these changes affect the estimation of item difficulty parameters. The results of this study have shown that item review by examinees does produce some changes to the examinee ability estimates and to the item difficulty parameters. In addition, these effects are more pronounced in shorter tests than in longer tests. In turn, these small changes produce larger effects when estimating the changes in the information values of each student's test score.