Both the new and old GMAT are computer-adaptive (CAT) tests. The computer-adaptive format presents questions according to each individual’s ability level. These questions are chosen from a pool of test questions categorized by content and difficulty. The first question is of medium difficulty. Every subsequent question is then determined by your responses to all previous questions. You are not allowed to change answers to previous questions as you proceed through the test, and you are not allowed to skip questions. A key part in preparing for the GMAT is to understand the CAT format and how your score is determined.