Indeed, the GMAT is testing not only your skills, but also its own future questions. These are called experimental GMAT questions. Although, you have no way of recognizing them on the test, GMAT Tutor’s academic director highlights what you need to know about them:
Experimental questions appear on the GMAT. These questions help GMAC discern their difficulty level and gauge whether the questions are testing the same concepts that the rest of the exam is testing.
Experimental questions can have a negative effect on test takers’ confidence and time management during the exam. Here’s a few things about experimental questions to take into consideration.
They don’t count toward your final score. This should give you more confidence when deciding on whether to attack a question.
Question difficulty levels are unknown. Many test takers attempt to measure their progress based on how difficult the following question is. But if suddenly you see a question you perceive as very easy or very difficult, it may also be experimental. This can also work to your benefit: if a question is very easy, this can give you a mental break from the hard ones and save you some time.
Do not assume that your score will be lower/higher because you are receiving easier/harder questions. You also cannot assume a question is experimental – we simply don’t know! Stick to proper time management, and remember that you can choose your battles. So keep fighting!
Up to 25% of questions can be experimental, and they can appear anywhere. Many people believe that 10-25% of questions on the GMAT are experimental and that most appear in the middle of the exam. However, GMAC has confirmed neither fact. Therefore, do not assume a set of question is experimental. Instead, concentrate your efforts on performing well at the beginning. Do not allow yourself to obsess too much at the beginning. Adhere to a proper time management strategy — this will get you closer to a higher score.
Read the original article on the blog of The Economist’s GMAT Tutor.