Hi M838TE,
The scoring algorithm on the Official GMAT is far more complicated than most people realize. Since that algorithm is proprietary, no GMAT company has an exact match for it, thus CAT scores can vary a bit based on the 'biases' involved in their respective designs. While the most realistic CATs available are the 6 from GMAC, retaking a CAT that you've already taken is NOT a realistic way to assess your skills - since you will likely see some 'repeat' questions that you have already faced. Unfortunately, seeing even a couple of repeats can 'throw off' the Scoring Algorithm and impact your pacing, energy levels, fatigue, etc. (meaning that they would likely all appear to be better than they actually are). Thankfully, the CATs from Kaplan,
MGMAT and Veritas are all 'close enough' to the real thing that they will provide you with a relatively realistic score assessment (assuming that you correctly take the CAT in a realistic fashion that matches the parameters that you will face when you take the Official GMAT).
Unfortunately, there's no practical way to convert the results from the OG Diagnostic Test to an equivalent GMAT Score (there are simply too many factors that don't 'match up' - including the number of questions, the order of the questions (and the ratio of the subjects), the fact that the paper Test does not adapt, the interface, your pacing, etc.). The only practical way to assess how you might score on the Official GMAT is to take a FULL-LENGTH CAT/mock under realistic testing conditions. You can take 2 for free at
www.mba.com (and they come with some additional practice materials). That score will give us a good sense of your natural strengths and weaknesses and will help provide a basis for comparison as you continue to study. A FULL CAT takes about 3.5 hours to complete, so make sure that you've set aside enough time to take it in one sitting. Once you have that Score, you should report back here and we can discuss the results and come up with a study plan.
I'd like to know a bit more about your timeline and goals:
1) When are you planning to take the GMAT?
2) When are you planning to apply to Business School and what Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich