The computerized version of the old GRE was a CAT (Computer-Adaptive Test), which means that the difficulty level of the questions you saw depended on your performance earlier in the test. Thus, the more problems you were solving correctly, the harder the problems you would get (and vice versa). The purpose was to give you a score that most accurately represented your understanding of the concepts and materials covered by the test. In short, a CAT test will adapt after you answer each question (either getting slightly harder if you answer correctly or getting slightly easier if you answer incorrectly). However, there are a few disadvantages to this type of test:
1) There is no option to skip or review questions. Because each question plays a critical role in the way the test plays out, you cannot skip questions on a question-by-question CAT test. Neither can you go back and review questions that you have already answered as this could drastically change the difficulty of the questions you should have faced.
2) It can be difficult to recover from a few incorrect answers at the beginning of the test. A small miscalculation on one of the earliest problems can set you on a downward trajectory that is tough to dig out of, resulting in a low score that may not accurately reflect your abilities.
These concerns are both addressed in the revised GRE, which is in the form of an MST (Multi-Stage Test). An MST is still an adaptive test, but it adapts from section to section rather than from question to question. Once you have completed a section, your score in that section will determine the overall difficulty of the next section. This allows you the freedom to skip and review questions within the section that you are working on without interfering with the adaptive element of the exam. Thus, it does not matter in what order you answer the questions in the first verbal and quantitative reasoning sections of the new GRE. What matters is how well you score on those first sections, because that will determine whether the second verbal and quantitative reasoning sections will be composed of easy, medium, or hard questions (and for the record, you want to end up with more difficult questions in order to achieve a better score).
ETS uses a process called “equating” to calculate your score on the new GRE. Equating is designed to accurately calculate your total score based on both your raw score (the number of questions you answered correctly) and the difficulty level of the questions you faced (easy, medium, or hard). Keep in mind that facing easier questions is not necessarily better. A student facing the more difficult problems will have a higher score after the equating process than if he or she had answered the same number of questions correctly in an easier section. Thus, it is to your advantage to do as well as possible on the first verbal and quantitative sections you see. A higher score here will set you up for a higher overall score. As with any test, the best strategy is to answer as many questions as possible correctly.
Another significant feature of the computer-based exam is that your essay is typed rather than written. This may seem like a minor difference, but the better your typing skills are, the more time you will have to think through and focus on the content of your essay. On the other hand, if your typing skills are rather weak, you may spend too much time trying to get enough words on the page instead of developing your argument (if this worries you, be consoled by the fact that at least you won’t have to worry about the legibility of your handwriting!). As an added plus you will be able to use basic editing tools such as copy and paste; however there is no spell-check. Therefore, make sure that you practice for the analytical writing section with a basic word processing program that will not autocorrect your spelling mistakes. The better you are able to simulate the conditions of the actual exam, the better prepared you will be on test day.
In sum, your approach to the computer-based GRE should be largely the same as your preparation for a paper-based exam. Practicing past GRE problems, brushing up on your vocabulary, and improving your writing skills are still the keys to scoring well on the new GRE. There is (and probably never will be) any real substitute for diligence and hard work. And when you take the actual exam, don’t stress out over the difficulty level of the questions that you see in each section. You can’t control what questions you are given, but you can control how well you answer them. Prepare diligently, study wisely, and then relax when you get to the test.