Developed by Educational Testing Services (ETS), the GRE exam has many similarities to the SAT. Both are now computer adaptive tests (CAT); no need to bring a pencil, pen or paper to the test site. In a CAT, you answer one question at a time; your answer to each question determines the difficulty level of the next question. As you answer questions correctly, the computer program increases the difficulty of your questions; when you answer a question wrongly, the computer program provides another of the same difficulty or a slightly reduced difficulty. Eventually, the computer program will tell you your score based on the correct level of your skill in that area.