It is worth noting that GMAC is now stating on its website that "
The practice exams use the same scoring algorithm as the official GMAT® exam."
On the old version of the GMATPrep desktop software, the scoring algorithm was NOT the same as that of the real GMAT, in part because the real GMAT used to have 23 experimental questions, and on the GMATPrep desktop software, every question counted.
Yet, GMAC is now telling us the opposite: that the
new online tests use the same scoring algorithm as the real GMAT. However, unless there are also 12 questions on the GMATPrep online tests that are
experimental/pretest/unscored, this is not completely true.
Source: GMAC WebsiteTheoretically, however, there is nothing stopping GMAC from throwing 12 experimentals into the GMATPrep software as well--especially since the software is now online and can be updated at any time. Until we run some
controlled, detailed simulations with the new online tests, there is no way to know whether some of the questions count, and some don't. If there truly are 12 unscored questions, then maybe the new GMATPrep software (online version) really DOES now have the same scoring algorithm as the real GMAT.
Or maybe it's just marketing hype. Time will tell...
-Brian