How to Get a Perfect GMAT Quant Score
How can you get the elusive Q51 on the GMAT? To start, let’s be clear that this question is mostly a matter of curiosity. You don’t need a 51 on Quant to score a 700 on the GMAT: technically, with a perfect Verbal score, you would only need a 36! You don’t need a 51 on Quant to get into HBS: the median score last year was 48. You don’t even need a 51 to be a test prep teacher (although if you want to work for MPrep, you do need to be in the 99th percentile)!
And this is a good thing, because as you’re about to learn, getting a 51 on Quant involves at least a little bit of luck.
Do you need to get every question right?
As a GMAT instructor, this is a tough question for me to answer. Not because the answer is complicated, but because the answer is (as dramatic as this sounds) a little dangerous!
Why? Well, suppose I say that you do need to get every Quant question right in order to score a 51. (We’ll see whether that’s actually true in a second). If that’s the case, then we’ve identified one way in which the GMAT is just like any other exam: in order to get a perfect score, you need a perfect performance.
You’ve spent your entire life taking other exams that worked like that. To get an A+ on a college final, you need to get pretty much every question right. There’s a simple reason for that: on almost all college exams, your score is a measurement of how many questions you got right.
So, if I say that getting a 51 on Quant means getting every question correct, it’s going to start to sound like the GMAT works the same way. You may be tempted to think that, just like a college exam, the GMAT is also trying to measure the number of questions you get right.
At this point, I’d recommend that you pause and take a look at this very interesting analysis from GMAT With CJ. In addition to the insightful commentary, CJ provides some data from his students’ score reports, comparing the number of incorrect answers to the final Quant score. What I found really striking was that almost everyone who scored between a 32 and a 48 got 10 or 11 questions wrong.
That’s more or less what Manhattan Prep came up with when we analyzed our own practice tests, which are based on Item Response Theory principles in the same way that the official GMAT is. (The number of incorrect answers on our practice tests is just a bit higher, because we don’t have experimental questions, which CJ excluded from his analysis of the real test.) Almost everybody misses almost the same number of questions, whether they’re getting a fantastic score or a so-so one.
In other words, the GMAT isn’t trying to measure how many questions you get right. And it doesn’t work the same way as a college exam.
But to get a 51 on Quant…drumroll…yeah, you need to get basically every question right.
Do you see why I hesitated to answer that question? You need to get pretty much every question right if you’re going to score a 51. But, because of the curious way that the GMAT’s scoring algorithm works, that doesn’t mean that more right answers = better.
A perfect (or almost perfect) Quant score is an exception to the rule
In order to calculate your score on Quant, the GMAT’s scoring algorithm goes through a process with a goal in mind. Its goal is to determine your “personal difficulty level”: the level of difficulty where you can sometimes, but not always, get questions right.
In order to do that, it keeps an eye on how well you’re doing at each point in the test. If you’re getting a lot of questions right, it amps up the difficulty. If you’re getting a lot of questions wrong, it tones things down. By making these fine adjustments, the test eventually settles on a level that reflects exactly how good you are at answering Quant questions (assuming you take the test correctly—for instance, you don’t rush or run out of time).
Suppose you’re at the very, very top of the scale and you can handle super-tough Quant questions. The GMAT will start out by giving you medium-level questions, just like it does for everyone else. You’ll get those questions right. Then, the test will give you harder questions. You’ll get those right too. It’ll eventually start giving you the very hardest questions it has. Surprise: you’ll get those ones right as well. But then, the GMAT runs out of difficulty levels. If it had even harder questions to give you, you’d probably start missing them eventually, and in the long run, you’d end up missing about as many questions as everyone else! But there aren’t any harder questions. In a way, if you’re scoring a 50 or 51, it’s because the GMAT isn’t hard enough to accurately assess you.
That’s fine, by the way. If you’re scoring a 51 on Quant, your quantitative skills are probably more than strong enough to handle everything that business school might throw at you. There’s no point in designing a test that can tell the difference between a 51 scorer who’s just barely hanging on, and a 51 scorer who could go all the way up to 60 (if 60-level questions existed). Plus, the GMAT would probably have to be a lot longer to do that, and who wants that?
So, that’s why a score of 51 on Quant corresponds to few, or no, wrong answers. It’s not because the test cares how many answers you get right. It’s because, once you’re at that level, the GMAT is pretty much throwing up its hands and declaring defeat: “fine, you’re so great at Quant that we can’t measure you with this test”! If you score a 51 on Quant, congratulations: you broke the GMAT.
Sounds great! Now, how do I get a perfect GMAT Quant Score?
If you’ve read this far, you understand what it means to get a “perfect” score on the GMAT, and why you need to get almost every question right to make that happen. We’re now asking a slightly different question: what does it take to get almost every Quant question right on the GMAT?
I could go into the skills involved at length, but instead, I’ll send you to this fantastic article from GMAT instructor Patrick Tyrell, who already did the work for me. He breaks it down into four skills: automaticity; use of alternate strategies; timing; and exposure. None of those skills is easy to develop, and given that a 51 score is more of a curiosity than a necessity, it’s probably not worth the work it may take to get there. But if you’re on the road to a 51, and you’re feeling inspired, click that link to Patrick’s article and start working on your study plan.
KEEP READING: Quick GMAT Math Hacks
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Chelsey Cooley is a Manhattan Prep instructor based in Seattle, Washington. Chelsey always followed her heart when it came to her education. Luckily, her heart led her straight to the perfect background for GMAT and GRE teaching: she has undergraduate degrees in mathematics and history, a master’s degree in linguistics, a 790 on the GMAT, and a perfect 170Q/170V on the GRE. Check out Chelsey’s upcoming GMAT prep offerings here.