jayneeniskeen wrote:If you're getting the same score over and over for your diags such as Princeton Review and GMAT Prep, should you expect the same score on the real GMAT? Or by how many points would you be able to go up or down?

GMATPrep is the only test that is truly representative of the actual GMAT. That being said, I think that I've heard that on a given day you should expect a 30-point variance in your test score--so if you're consistently scoring a 700 on GMATPrep, don't be surprised if you score anywhere between 670-730 on the real test.

This is not a perfect rule by any means. Many people here have reported scores that have been significantly different from their practice exams.

Good luck!

By the way, Stacey Koprince has written some fine comments addressing this topic: https://www.beatthegmat.com/viewtopic.php?p=21929#21929

You're welcome!