Knewton CAT Algorithm

[sunman]

Alright, so it's only 10 days before my GMAT retake. I decided to brush myself up by taking a free Knewton GMAT CAT. Never tried this brand before, but since I maxed out GMATPrep, MGMAT and 800score, I needed a new CAT to see if my skills have eroded or not (since I'm deploying to Afghanistan soon, predeployment training has been sucking up my study time.)

Came out with a 46Q, 43V and 720 Overall.

Is anyone somewhat familiar with how the algorithm works? (Knewton employees maybe?)

Because I pretty much crushed the Quant, even though I got 3 or 4 wrong in a row...

Anyway, results are below. Kind of upset that I scored in the 73rd percentile on quant again. Just seems to be my nagging critical vulnerability:











Anyway, 10 days to go until (re)game day. Having a hard time getting my quant up to the level that I want. Don't knows how this came out to a 46Q, but it did:

[gmatboost]

I cannot comment on the first part of your question, but if you're interested in trying to get your quant level up, I can suggest a few resources:

1. GMATBoost.com (Full Disclosure: Please note that this is my site)
2. "Advanced GMAT Quant" book by Manhattan GMAT
3. "Kaplan GMAT 800" book

[rijul007]

Even i have a similar ques regarding the scoring algo that knewton follows..





I just got a few questions wrong somewhere in the middle(Q16-21) and then correctly answered all the remaining questions..
still got just a 46..



@sunman.. i dont think you should worry much.. i am sure you would do pretty well..
All the Best!!

[Jessie@Knewton]

Hey there,

We get a lot of questions about CAT scores and why they sometimes don't seem to match a student's perceived performance level. This has to do with the way these particular exams are scored; the scoring is much less about how many questions you get right or wrong, but rather which questions you get right and wrong.

The CAT algorithm estimates your ability based on a variety of criteria, including the difficulty of a question. After each question, it evaluates your response and updates this estimate. When the test is over, the algorithm converts your quantitative and verbal ability estimates into the quantitative and verbal scaled scores, and then separately combines your quantitative and verbal ability estimates to calculate the overall score.

Therefore, the number you get correct and incorrect on a CAT is sometimes seemingly incongruous with your scaled scores. Additionally, all CATs have experimental items, and you can get all of those correct or incorrect and they won't change your score, but will alter your perception of what your score should be (since you can't see which ones were experimental). All of this is very much the reason the real GMAT doesn't give you item data -- you just get your scaled scores, so that the confusion of understanding the complicated way in which the CAT works is out of sight of the test-taker.

Hope this clears up the confusion around scoring. Feel free to reach out with any more questions!

All the best,

Jessie
Knewton GMAT Team

[sunman]

i'm not blasting Knewton or anything, but from what I've seen, it seems like the major test prep companies (Kaplan, Knewton, Princeton Review etc) ask their employees to defend the reputation of their products on these forums.

Really, I'm thankful to Knewton for offering a free CAT so I can brush up on my skills when I have already maxed out on the MGMAT and 800score.com CATs, but that logic is really kind of dubious. I think we both routinely test at the 700+ level, and when we get 31/37 and 33/37 wrong on quant respectively, it's probably a lot more likely that we answered difficult question incorrectly than an easier one.

I don't know. It's whatever. A 720 on a practice exam isn't going to make me shed any tears. I understand what an incredibly onerous process it can be to produce an algorithm that mirrors the official GMAT.

I think Manhattan GMAT probably comes the closest. Overall though, I had a good experience with the Knewton CAT, even if I was surprised by my scaled quant score.

At this point, as long as I am scoring consistent 700+s, I feel pretty good about my retake on Monday.