You can never be completely sure of this. But go thru this article, the scoring is discussed.

https://www.crackverbal.com/blog/gmat-sc ... ied-partly

I hope it helps. These are just approximations +-10/20 is not unusual.

Great link, Akhil (so thanks to Arun@CrackVerbal, too).

At the GMAT Summit last week they went through this discussion, too, so I might as well pass that along. A few notable points:

-The 200-800 score is the final report, sent to schools to stay consistent with the old paper-and-pencil (pre-1997) test scoring system, but the scoring algorithm used in the computer uses its own system and just converts the 0-60 and 200-800 values over as that last step in reporting.

-Each scaled score has a corresponding "interim range" which spans 2-3 numerical values, so your 50 on quant might correspond to a range of 60-62 on that GMAT computer scale (again, the computer uses its own numbers that are more consistent with how the CAT algorithm scores you, then the system converts to the familiar display numbers). Those interim scores for quant and verbal are then combined and your "interim sum" (which now may span 5-6 potential values since you're adding two ranges together) is then converted to your 200-800 score.

So not all 49s (scaled score) are created equal - your 49 might be a "high 49" (at the higher end of the interim range of scores and someone else's might be a "low 49". When the computer uses its interim value, if you have a high/high split of interim values for the same Q/V scaled scores and someone else has a low/low split on theirs, your 49/39 might be a 730 and theirs a 710. The 3-digit 200-800 score is valid - it's just that you don't see the full process that goes into calculating it.

-So as an example (courtesy Dr. Rudner's presentation last week), if you have a 50Q/31V, that has a potential range of:

Quant: 51 scaled --> 60-62 interim range (you could be a 60 or a 62 and still end up at 51 scaled)
Verbal: 31 scaled --> 42-43 interim range

Total: 102 - 105 on the interim scale, on which 102 would correspond to a 670 and 105 would correspond to a 690. So the same two scaled scores could swing 20 points either way on the overall score, and that's because the overall score is calculated using the computer's numbers, not your score report numbers.