
Ammon B. answered 03/14/19
Elite-trained GMAT Tutor (780)
Erick:
Comparing score across platforms can be tricky because each platform has written their own exams, so they might be different in important ways. I personally put the most weight on my OG guide scores because those questions were written by the makers of the GMAT. In fact, at least some of the questions come from previous GMAT exams. Because of that, I knew that the OG was the closest I was going to get to a real GMAT.
At the end of the day, these tests are written by humans who are full of bias and make mistakes. You have no guarantee from other test prep providers that their questions will be representative of the GMAT. Of course, they usually are pretty close and some do a pretty good job, but still, nothing is as good as the real thing.
On the other hand, if you feel like Manhattan's tests are much harder than the OG, and you're doing well on those, then you should be feeling pretty good.
Hope that helps.