The GMAT is a computerized test that adapts to your performance. This format is called a CAT (computer-adaptive test). As you take the test, the computer will select questions based on your performance. If you get a question correct, the test will select a more difficult one next. If you get a question wrong, the computer will select an easier one next. Thus, the test adapts to your performance.
Benefits
This format offers many benefits.
The test can focus on your score range and create a more accurate score.
You have the option of canceling the score immediately after the test (before you see your score). If you accept, you will have immediate access to your math and verbal scores.
You take the test in a private cubicle instead of a classroom.
You can schedule the test at your convenience instead of taking it on set days.
Negatives
The most significant negative factors of the CAT revolve around the added difficulty of the format. The CAT is much more difficult than the paper test. Here is why:
You have to stare at a screen for several hours.
Your timing will have to be much more precise and is more difficult.
You can't skip questions.
You can't write directly on the test booklet and have to re-copy questions onto scrap paper.