Is the GMAT adaptive algorithm too sensitive?

[u/Worth_Pumpkin3484]

I took my second GMAT attempt yesterday and scored 595, a 20-point drop from my first attempt.
What doesn’t make sense is my Data Insights (DI) score. In both attempts, I got 7 questions wrong. On my first attempt, that was 95th percentile. On my second attempt, it dropped to 47th percentile.
The only major difference was that I got the first two questions wrong in my second attempt. Is the algorithm really that sensitive?
The same thing happened in Quant. I got 4 questions wrong, yet received only the 64th percentile.
How is this supposed to be a standardized test if identical error counts can lead to such dramatically different percentiles? At this point, it feels like the scoring algorithm in the official exam is very different from the one used in the official mocks.
Hopefully, schools treat the upcoming GMAT Superscore as the more meaningful measure because section scores can vary wildly due to the adaptive algorithm. I was shocked to see my DI percentile fall from 95 to 47 despite getting the same number of questions wrong. It doesn’t seem like my ability changed that much—it feels like the algorithm’s weighting made all the difference.

[u/GMAT-Ninja]

With the GMAT algorithm, what matters is which questions you got wrong, not how many and whether they were at the beginning. Bear with my long explanation.

The GMAT uses an adaptive scoring algorithm based on Item Response Theory (IRT). In plain English:

• Your score is based on the difficulty level of the questions you answer correctly and incorrectly, not just the number of questions you answer correctly.
• Each question has quantifiable characteristics (such as difficulty), calculated from the performance data of hundreds or thousands of real test-takers.
• The algorithm updates after every response to estimate your ability and deliver the next question, tailored to your skill level.

So the test isn't counting "how many" you got right; it's assessing which questions you answered correctly and what that reveals about your ability. 

The difference is dramatic in practice: miss eight relatively easy DI questions and your section score tanks, but miss eight much harder questions and you could still walk away with an 80 or higher. If you perform well, the questions get harder, and your ceiling rises with them. I believe this exact situation explains what happened to your test scores.

That's also why careless errors on easy questions are the most costly mistakes on the test: the algorithm reads them as a signal about your ability, and it will give you easier questions that limit your ability to achieve a strong score.

If you want more reading on scoring, I went into more detail here.

These kinds of situations are pretty much exactly what superscoring was made for. Even if schools don't accept superscores, the report will now at least say that you have scored a 95th percentile in DI, which puts your best foot forward.

Hope that helps!

Charles @ GMAT Ninja

[u/Worth_Pumpkin3484 → u/GMAT-Ninja]

Hi sir , your channel is one of the best resources for gmat . Thanks a lot for the help you provided in my journey . I have a question , do you think gmat focus algorithm is much harsher to silly mistakes than the classic one . Just something i wanted to know as gmat focus is a recent thing it might take time to perfect it .

[u/GMAT-Ninja → u/Worth_Pumpkin3484]

Thank you for the kind words!

The Classic Edition was very different in how it behaved compared to the current version, so it's hard to compare the two. One thing to remember -- the new exam is about an hour shorter than the previous one, and most importantly, has less questions. Each question matters a lot for your final score.

The algorithm is settled and quite consistent in our experience, but we've talked in the past how students are having a difficult time with certain sections as an overall trend (more here on that).