What is the reason for Experimental questions/Unscored questions on the GMAT?
1. Estimate difficulty level of questions to be included in future tests. Questions on the GMAT tests change every calendar month or every 30 days – that’s why you can take the test only once every 31 days. Since GMAT is an adaptive test, that’s quite a few new questions that GMAC needs to develop monthly and one of the hardest things about developing new questions is understanding how hard/easy they are. To help address this issue, about 20-30% of the questions you will see on the test are experimental questions (to be used on future tests) that GMAC is trying out and measuring difficulty level. This is one reason some test takers get scared when suddenly they get an easy question after a hard one, which could mean that they missed previous question, but in reality they just got served an experimental question that does not have a difficulty level assigned to it yet. 2. Measure question fit and quality – regardless of difficulty, a question may still be of poor quality – meaning it do
