I personally find the Kaplan CAT and the scoring algorithm quite random.
Just completed the first CD CAT and scored a miserable 590, (Q50, V28) my lowest ever by a huge margin. Have been scoring consistent 690 - 710 range on
MGMAT and GMAT prep.
Coming back to the scoring algo, in Q i had 3 questions wrong and got a raw score of 50, fair enough. But then my partner did a test on-line and got 1 question wrong but got a 48. Absurd !
With regards to the CD Verbal, maybe I did not do as well as i wanted to but then again I did not feel that the questions were getting easier. Given i was doing badly i should have expected the level of questions to go down but that did not happen. Now on-line verbal was even more of an absurdity, she got first 1/3 questions as SC, then the next 1/3 as CR and the last bit RC ! How can you call that a Computer adaptive test !
To add to that a raw score of Q50 and V28 should translate to ~640, but I got a measly 590.
I may be biased based on the 1 test that I have done. So will probably give another test before deciding if its worth taking these scores into account or just abandon the CAT scoring and use the questions as a practice.