The Story of a Lucky GMAT Test Score
A.k.a. How Lucky Was Mr. Fat Pants?
UPDATED FOR THE NEW GMAT IN 2024
Disclaimer: this article contains several stories about some of our previous students. These students took the “old” version of the GMAT, so the scores referred to do not match the scoring system on the GMAT Focus Edition, which was introduced in November 2023. However, the punchlines from these stories still hold true, so we decided to leave them intact in the hope they’ll help inspire you to achieve your GMAT goals.
If any of you are expecting a practical, useful article about improving your GMAT, I apologize in advance: this is going to be a pretty useless, vaguely technocratic article about standardized testing. You’ve been warned.
A couple of years ago, I wrote an article about a fellow named Mr. FP (Mr. “Fat Pants”), who once wrote a brilliant MBA application essay about his lunchtime festivities at the office. Mr. FP deserves to be a legend because he actually used the phrase “fat pants” in his MBA admissions essays, but he’s also notorious (in my little GMAT world, anyway) for springing a huge test-day surprise on both himself and his GMAT tutor: he scored a 680 and then a 640 on his only two full-length GMATPrep practice tests, then nailed a 720 on the actual GMAT — just a few days after the 640.
Mr. FP is a great guy who ultimately kicked all sorts of ass at a top-10 MBA program, and he clearly deserved to be there. But we agree that he got a little bit lucky on the GMAT.
But how lucky did he get? And can we somehow quantify his luck on the GMAT?
The quick answer is that Mr. FP was pretty darned lucky. As for quantifying his GMAT luck, you’ll need to dive deep into the bowels of your GMAT score report. (Sorry for the image; do you really want to dive “deep into the bowels” of anything?)
GMAT score reports include some mumbo-jumbo about something called the standard error of measurement, and GMAC will tell you that the standard error of measurement is about 30 points on the GMAT. But what exactly does that mean?
What is “Measurement Error” on the GMAT?
To understand the idea of measurement error on the GMAT, imagine for a moment that you have something called a “true” GMAT score. There are two ways to think about a “true” GMAT score. First, you could imagine that it’s the score you would receive if the GMAT always did a 100% perfect, 100% consistent job of measuring your verbal and quantitative reasoning skills (or whatever it is that the GMAT actually measures).
If that doesn’t seem intuitive, imagine this: you’ll take the GMAT, I’ll wipe out your memory of the exam using the “flashy thingy” from the Men in Black movie so that you don’t remember any of the questions, then I’ll send you back to the very same GMAT test appointment using a time machine from the Back to the Future movies. I’ll do this an infinite number of times. Assuming that you don’t get brain damage, the average score on your infinite number of GMAT exams would be your “true score.”
Of course, you wouldn’t always get exactly the same score on every single test appointment, even if we conjure some Hollywood magic to eliminate all day-to-day variations in your test-taking behavior. The truth is that GMAT scores are a little bit random, since the GMAT selects a different, relatively small sample of questions each time you take the exam. Even if you behaved exactly the same way every single time you took the test, you’d see a slightly different batch of questions on each exam – and you’d earn slightly different GMAT scores from one day to the next. That’s an inevitable part of standardized testing, especially on an adaptive exam that spits out somewhat randomized questions.
Back to the technical part: the standard error of measurement is basically a measure of that random variation in your scores from one GMAT exam to the next, even if we assume that you’re a robotic test-taker who always behaves exactly the same way.
If you’ve taken a few statistics courses, you could think of the standard error of measurement as the rough equivalent of a standard deviation for your GMAT score: since the GMAT’s standard error of measurement is around 30 points, roughly 2/3 of all test-takers will score within 30 points of their “true” GMAT score, and roughly 95% of test-takers will score within 60 points of their “true” GMAT score.
The Role of Luck in GMAT Scoring
With the standard error of measurement in mind, we can safely say that luck does play a role in GMAT scores, albeit a relatively small one. Your GMAT score could plausibly fluctuate by around 30 points from day to day, but you aren’t terribly likely to gain or lose 60 points simply by random chance.
Back to the original question: yes, Mr. Fat Pants seems to be a very lucky man. We’ll never know Mr. FP’s “true” GMAT score, but based on his homework and official practice test results, I would have wagered that he was in line for a 660 or so—halfway between his two mba.com practice test scores. If we pretend that 660 really was his “true” GMAT score, then Mr. FP scored 60 points—or two standard errors of measurement—above his “true” score.
If you’re a statistics geek, you’re welcome to bust out your favorite z-chart and do the calculations yourself, but there was roughly a 1 in 40 (2.5%) chance that Mr. FP would receive a random gift of 60 or more points from the GMAT gods. And keep in mind that any random, luck-based deviation from your “true” GMAT score could work in your favor—but it’s equally likely that it will work against you. If 1 out of every 40 test-takers will earn at least 60 “measurement error points” that they don’t “deserve,” then 1 out of every 40 test-takers will lose at least 60 points on their GMAT score, just from bad stinking luck.
The gods of random chance are sometimes very kind, but they’re also randomly very cruel.
So if you’re still 60 or so points away from your ideal GMAT score and you want to roll the dice, go for it. But your odds of a Mr. FP-esque stroke of good luck aren’t all that good, and it’s probably better to hit the GMAT books hard and make your own luck.