GMAT SPLIT SCORE - Brief by Jeff Sackmann

Found a nice article on gmat score splits

Source:http://www.gmathacks.com/cat-strategy/what-is-the-ideal-gmat-split-score.html

Your overall GMAT score--the number between 200 and 800--is generated from a combination of Quantitative and Verbal "scaled scores." The Q and V scaled scores technically range from 20 to 60, though scores near either end are not used.

The numbering system isn't what's important. Instead, focus on percentiles. Often, you'll hear people report their scores this way: "90th percentile on Verbal, 70th percentile on Quant." So, how does the GMAT combine those section scores into the overall number?

To understand how it works, recognize two things: It's relatively rare that test-takers have equal skill levels on the two halves, and business schools (and by extension, the GMAT) value balance.

Because most people are better at one section or the other, students who are equal are rewarded. For instance, someone who scores the coveted "80/80 split"--an 80th percentile score on each of the two sections--will have an overall score of about 700: better than the 90th percentile.

Thus, your overall score is not just the average of your two section scores.

Part of the reason the 80/80 split is so highly valued is that is reflects a broad skillset that most applicants don't have. Many students have tremendous Quant skills but struggle with the language, while others with more liberal arts backgrounds excel at the Verbal but are frightened away by math.

This shows up in the overall GMAT score. While a 70/90 split is an excellent score (regardless of which one is which), it is not quite as good as the 80/80. A 60/99 is still solid as well, but the result is worse than that of the 70/90 split.

The ideal split score, then, is an equal one. If your practice test scores are showing a huge gap between the two section percentiles, your overall score will increase more if you are able to improve on your weaker half of the exam.