APPENDIX A

How Much Can a GMAT Score Change?

The following appendix is adapted from The GMAT Unlocked, a white paper from Kaplan’s Research Series. For more information, or if you’re interested in any of our classroom or tutoring programs, please visit our website at KaplanGMAT.com.

Whether you are just starting your studies or whether you have already taken the GMAT and are looking to retest, there’s likely one question on your mind more than any other: how much can I improve my score?

This is an important practical question. If you have a baseline score that’s far from your target, you need to know whether you can reach your target and how much work it will take. Or, you may have received a low score on the GMAT, and you’re wondering how much it might go up if you retook the test in a month with a better mindset and some further study under your belt.

While the exact answer to the question of score improvement is as unique as your particular talents and circumstances, there is some information that’s worth knowing. There are actually two questions regarding how much a person’s GMAT score can change within a given period of time:

  1. How much do scores vary?

  2. How much can scores be improved?

Let’s discuss some important facts related to these two questions and examine what these facts mean for your preparation.

HOW MUCH SCORES VARY

Scores can vary widely, but they tend not to. The testmakers present two statistics on the subject that tell slightly different stories.1

First is the “reliability” of the test. The GMAC answers this question directly by saying that you are 92 percent likely to get the same score on the GMAT if you take the test and then retake it (without any study in between). That’s probably a lot more reliable than you expected. The testmakers go on to make the following statement:

The current standard error of measurement for the GMAT Total score is 29, which means the reported GMAT Total score is within 29 points above or below a score reflecting true performance—a repeat test taker with Total scores within 29 points of each other knows he or she has performed consistently.

So there is little reason to retake the GMAT in the hope of improving your score without substantial preparation in the interim. The standard error of measurement also gives you some perspective on score improvement. Any score improvement of 30 points or more constitutes a major accomplishment. In other words, 30 points may or may not sound like a lot on the GMAT scoring scale to you—but it is a lot.

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The Magic Number Is 30 When Evaluating Scores Against True Performance

HAVING A “BAD DAY”

As GMAT teachers, we see applicants have a “bad day,” recognize it as such, and walk away with unrealistically high hopes about how much their score will go up after a simple retake on a “good day.” The figures above—the 92 percent reliability and the 29-point standard error—indicate that your score on a good day is likely to be the same as your score on a bad day. Furthermore, if your score on a good day is any higher, it’s very, very unlikely to be more than 30 points higher, unless you have raised your skill level through preparation. There is hope for score improvement (we at Kaplan have seen hardworking students make tremendous score gains), but it lies along a path paved with practice.

One exception to this rule is the off day caused by sickness or a traumatic life event. If you have reason to believe that specific circumstances have caused you to underperform significantly, you should probably cancel your score on Test Day. This scenario is why it is so important to go into Test Day knowing both your goal score and the minimum score you will accept without canceling (see the section on “Cancellation and Multiple Scores Policy” in chapter 21 for more detail). Even if you don’t cancel, you might wish to schedule another testing appointment in the near future to have a good shot at the exam. Other disruptions that may affect your performance, such as a fire alarm going off or computer malfunctions during your test, can also be good reason to cancel your scores or retake the exam. If the disruption is caused by an irregularity in testing conditions, you should report it to the test administrators immediately and follow up through the appropriate channels to make sure that the situation is remedied fairly.

THE “GAMBLE RETAKE”

Maybe you had a fine day at the test, but you got a 690 and you’re aiming for one of the top ten or so programs, where the average score is close to 720. You hear the standard error is 29 points, which is almost exactly the size of the increase you’d like. So you wonder whether you should gamble on a retake—simply take the test again and hope to do better. Knowing that you can simply cancel your score if you do the same or worse on the test provides a good measure of insurance against those risks. However, when you are contemplating such an investment of money ($250 for test registration), time, and stress, it’s first worth considering logically what your actual chances are of improving your score without additional dedicated study in the interim.

Here’s a breakdown of the gamble retake. Let’s consider three cases:

  1. Say your true score (at your current skill level) is 690. In this case, you are quite likely to get a 690, or close to it, on a gamble retake. Moreover, you’re as likely to get a 660 on your gamble retake as a 720.

  2. Say your true score at your current skill level is a 720. This is the possibility you want to believe is the case. In this case, your 690 score was somewhat lower than your true score—not necessarily because you had a bad day but perhaps due to statistical variation in scores. In this case, on your gamble retake, you’re most likely to score at or near 720.

  3. Say your true score at your current skill level is a 660. This case is the mirror image of case #2. In this case, your 690 was indeed a fluke, but in your favor. You’re likely to score at or near a 660 on your gamble retake, and you’re just as likely to score under 660 as above 660.

There are other possibilities, of course—your true score at your current skill level could be 680 or 700 or something near this range. It could even be as far away as 600 or 780—but such cases are very unlikely (and if you’d like to gamble on those odds, you may want to dedicate your B-school tuition to playing the lottery instead). But given the statistical reliability of the GMAT, the most likely case of all is #1. Cases #2 and #3 are less likely—and each of those is as likely as the other.

So even if you are only 30, 20, or 10 points shy of your goal, the gamble retake is not a particularly good gamble. The risk posed by case #3 is entirely mitigated by the fact that if you underperform on your retake, you may simply cancel your score. Nevertheless, a straight-up gamble retake will produce the same score more often than any other result—the most likely outcome is a simple waste of time and money. In general, a retake is the right move only if you have a month or two beforehand to devote to serious study.

IMPROVING YOUR SCORE

Devoting your time and focus to regular study, on the other hand, is no gamble; it’s a proven way to gain familiarity with, and ultimately mastery over, the test. Rather than guessing at your true skill level as we discussed above, you can accurately assess your performance by looking at the range of scores after you’ve taken several Kaplan practice CATs. While the exact score will likely vary from test to test, the scores taken together should reveal a consistent pattern of performance. As you continue to practice, look for upward trends. Keeping the standard error of measurement in mind, don’t focus too minutely on the individual scores but rather on the larger picture they reveal. Use this book and your online resources to move that range upward over time. Keep working to improve your performance until you’re comfortable with the score range you are seeing consistently on your CATs. With practice, you can feel confident that you will receive a score on Test Day that reflects your highest attainable level of ability.

1 http://www.gmac.com/gmac/thegmat/gmatbasics/whyrelyongmatscores.htm