13 Most Common GMAT Mistakes and How to Avoid Them


Everybody’s afraid of making mistakes on the GMAT, and it’s hard to know sometimes exactly where you’re getting tripped up in your prep or on the exam. But you can be a step ahead of the game if you avoid the most common traps for test-takers.

In this article, I’ll go over the most common mistakes in GMAT prep, strategy, and specific sections, so you can weed out any errors you might be making now and avoid them in the future.


Top 5 GMAT Prep Mistakes

GMAT prep is tough, and it’s easy to make mistakes along the way. Let’s go over the top five errors students make in GMAT prep so you can study as effectively as possible.


#1: Studying Without a Plan

Some test-takers take a “more is more” approach to GMAT prep. That is, they take practice test after practice test, and think that will be enough to improve their score. Doing this, you run the risk of simply repeating the same mistakes over and over without any tangible improvement. Your GMAT prep needs to be geared towards your personal needs, how much you need to improve, and what specific skills you need to build.

Quality is more important than quantity when it comes to GMAT prep, and quality means making a plan and a specific schedule. Make specific goals for yourself each week. Instead of “study for two hours,” a goal for a single study session could be to review five sentence correction questions you completed in previous practice tests that feature errors in pronoun usage and to complete a customized fifteen-question sentence correction practice quiz in fifteen minutes.

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#2: Not Using Computerized Adaptive Practice Tests

It’s important to mimic the conditions of the GMAT when you study. Prep books can be tempting as they advertise themselves as “comprehensive” study guides (and they can certainly be helpful in providing overviews of each section and test-taking strategies), but to get a realistic, reliable sense of what your score will be on the exam, you’ll need to take practice tests in the same format as the real test.

The GMAT is a computerized adaptive test (CAT), meaning that it adjusts to your skill level in real time, using an algorithm to “decide” what kinds of questions to give you next (difficult, medium, or easy) in real time. As many of your practice tests as possible should also be in CAT format. The best source of realistic GMAT practice tests is the Official GMATPrep Software, which contains two full-length practice tests authored by the Graduate Management Admissions Council (GMAC). Find more high-quality CAT practice tests here.


#3: Not Focusing On Your Weaknesses

Some students focus on all sections and question types equally, or spend more time on the sections in which they’re already excelling and want to boost their score a few extra points. Instead, you should hone in on the area(s) in which you’re weakest, whether that’s a particular section or question type, a test-taking issue such as pacing or calculating solutions in your head, and/or a fundamental skill set, such as grammar or basic math.

MBA admissions committees generally frown upon large score disparities between sections, particularly between the quant and verbal. So even if you’re doing very well in one section, it’s important to bring the other one up to that level (even if they won’t be exactly equal). And if you really struggle with a specific question type, it can throw off your game throughout the exam, as you’ll be nervous to encounter it, get tripped up on it, and potentially waste time as well as lower your score.

Once you take an initial diagnostic practice test (learn more about that here (coming soon)), you’ll have a good idea of what your weaknesses are. Your GMAT study plan should be focused on those weaknesses, and the majority of your prep time and energy should be spent on the areas you struggle with the most.


#4: Cramming

It can be tempting to try to shove all of your GMAT prep in to the last few weeks before the exam, but whatever you do, don’t try to cram!

Studying for the GMAT takes time, a prep routine, and a plan. You’ll need to delve into your specific weaknesses, complete drills, and gauge your progress using several practice tests in the same format as the real exam. It will also likely take regular study sessions (not just a few longer ones) to build any fundamental skills you might be missing. Because of this, it’s best to study for at least ten hours a week over several months. Plan for at least three months of studying when you create your GMAT prep schedule.

If it’s getting close to your exam date and you truly haven’t prepared enough, it’s best to reschedule your GMAT. Check out our detailed guide to rescheduling your exam date here.


#5: Not Getting Enough Rest

Pay attention to your emotional and physical health as you prep for and go into the exam, in addition to your mental preparation. The week before the GMAT, you should still be prepping, but not more intensively than in the previous months. The day before the exam, you shouldn’t study at all, in order to give your mind a rest.

Most likely, you won’t retain anything you study the night before in time to improve your score on the GMAT anyway. Being at your emotional and physical best on the day of the test is an important part of performing well on the exam.


Get your beauty rest! Sleeping well the night before the GMAT will help you be in tip top shape for the exam.
Get your beauty rest! Sleeping well the night before the GMAT will help you be in tip top shape for the exam.


Top 4 GMAT Strategy Mistakes

So, now you’re ready to take the actual GMAT. What kinds of mistakes do test-takers make in their approach to the exam? Let’s go through the four most common ones.


#1: Refusing to Guess

Some students have a tendency to agonize over GMAT questions they’re struggling with, or to take too long on the first five to 10 questions.

The GMAT is not designed for you to get every single question right. Instead, it’s in a computerized adaptive format that uses an algorithm to adjust to your skill level as you go along, and to give you an appropriate number of easy, medium, and difficult questions, as well as the appropriate number of each question type. It’s more important to get through the entire test than to answer every single question you’re given correctly.

If you’re struggling with a question, try your best at implementing the process of elimination, but don’t waste too much time. Take your best guess and move on to the next question.


#2: Not Taking Notes

Sometimes, test-takers make the mistake of not taking notes on the provided scratch pad as they read a question or figure out the answer. This might seem like it will save time, but not taking notes might actually lead you to to take longer. For example, you might forget important details from a reading comprehension passage, causing you to select the wrong answer choice or to have to go back and reread the passage several times.

To avoid this problem, take notes during your practice tests and drills so you’re used to doing so by the time you get to the real exam. To mimic the circumstances of the GMAT, use a legal pad and a thin marker or the simulated GMAT scratch pad available from Manhattan Prep. You can find more detailed information about the GMAT scratch pad here.


#3: Rushing Through Questions

Many test-takers mistakenly try to save time by rushing through questions and answer choices without fully reading them. You need to read the passage and each GMAT question fully to 1) keep track of all the information you’re being given, including any significant details and 2) know what the question is asking you to do.

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For example, a critical reasoning question may ask you to find the information that would weaken a given argument. Students who don’t read every word of the question or skim over it might instead instinctively look for the answer choice that would strengthen or support the given argument. You’re doing yourself a disservice and risking making careless errors if you skim any part of the question.


#4: Trying to Beat the Computerized Adaptive Format

Some students try to guess the difficulty level of a given question as they go along or otherwise try to “beat” the CAT format of the GMAT by focusing more on hard questions than on easy ones.

Simply put, this is a distraction, and it’s virtually impossible to “beat” or “trick” the algorithm. For one thing, it’s far more difficult than you think to guess the level of a given question, as what you find difficult might be different from the norm or might vary from moment to moment or under the pressure of taking an exam.

It’s a waste of time, effort, and focus to worry about the CAT format as you go along. Just do your best on every question, guess if you need to, and try not to worry about the outcome.


Taking notes as you take the GMAT might seem like a waste of time, but it may actually help you complete the test more quickly.
Taking notes as you take the GMAT might seem like a waste of time, but it may actually help you complete the test more quickly.


Top 4 GMAT Section Mistakes

In addition to mistakes in prep and test-taking strategy, there are some common errors that are specific to each different GMAT section. Let’s go over the four most common GMAT section-specific errors.


#1: Never Choosing Sentence Correction Answer Choice (A)

Sentence correction questions provide you with an initial sentence that may or may not contain an error. Answer choices (B) through (D) rewrite the sentence, while answer choice (A) is identical to the given sentence (so it’s the “no error” answer choice).

Many GMAT test-takers are wary of answer choice (A) on sentence correction questions and avoid it. Don’t fall into this trap and look for errors that may not be there! Answer choice (A) is as likely to be the correct option as any other answer choice on sentence correction questions.


#2: Calculating on Data Sufficiency Problems

Data sufficiency problems ask you to determine whether given statements or pieces of information are sufficient to answer a mathematical question. Many students are tempted to spend time on specific calculations and solve for x in an equation instead, even though the question doesn’t ask them to do so, which wastes precious time.

By doing this, you’re essentially solving the wrong question, as data sufficiency problems never ask you to actually solve an equation. Instead, they ask you to figure out what information you would need to solve an equation or answer a question. This means that spending time on specific calculations is usually a waste and unnecessary, or may even cause you to get confused and answer the question incorrectly.

If you’re running into this problem, devote targeted practice time to completing data sufficiency practice questions, reading the in-depth answer explanations, and coming up with your own plan as to how to tackle this question type.


#3: Assuming Too Much on Critical Reasoning Questions

A common mistake on critical reasoning questions is making assumptions that go too far. To avoid assuming too much, focus only on the information you’re given in the initial argument. Don’t rely on outside knowledge, or take the information you’re given to an extreme.

One clue that you might be making assumptions is if you start relying on absolutes. Let’s take a look at one example from the GMATPrep Software.

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Increases in the level of high-density lipoprotein (HDL) in the human bloodstream lower bloodstream cholesterol levels by increasing the body’s capacity to rid itself of excess cholesterol. Levels of HDL in the bloodstream of some individuals are significantly increased by a program of regular exercise and weight reduction.

Which of the following can be correctly inferred from the statements above?

A) Individuals who are underweight do not run any risk of developing high levels of cholesterol in the bloodstream.

B) Individuals who do not exercise regularly have a high risk of developing high levels of cholesterol in the bloodstream late in life.

C) Exercise and weight reduction are the most effective methods of lowering bloodstream cholesterol levels in humans.

D) A program of regular exercise and weight reduction lowers cholesterol level in the bloodstream of some individuals.

E) Only regular exercise is necessary to decrease cholesterol levels in the bloodstream of individuals of average weight.

Let’s take a look at answer choices A, C, and E. All of them contain inferences that make too many assumptions and are thus incorrect. In answer choice A, the assumption that underweight individuals don’t run “any risk” of high cholesterol levels goes too far; we can’t assume from the fact that weight reduction can contribute to lower cholesterol levels for some individuals that weight is the only factor.

Answer choice C also goes too far. No other possible methods of lowering cholesterol levels are discussed in the original argument, so we can’t infer that exercise and weight reduction are the best methods of increasing HDL levels.

Similarly, in answer choice E, the assumption is that all individuals of average weight can lower their cholesterol with exercise alone. The original passage explicitly states that exercise and weight reduction allow some individuals to increase HDL levels.

Clue words that key you in to the fact that you might be assuming too much are “never,” “best,” “worst,” “all,” “none,” “always,” and “only.” Often, answer choices that include these words aren’t correct—though that, too, is not a 100% absolute. But they should serve as red flags, and you should evaluate those answer options more closely. Ask yourself, “Do I really have enough information to come to that conclusion based on this passage alone?”


#4: Not Making an Outline for the Analytical Writing Assessment

Some GMAT test-takers, concerned about the 30-minute time limit on the essay, start writing as soon as they skim the analytical writing assessment prompt. You should always take the time to create an outline before you start writing your GMAT essay.

Making an outline, either on your provided scratch paper or in the text box (make sure to erase if you use this method!), is an important step in the writing process. It will help you to keep your thoughts organized, structure your essay in a way that makes sense, avoid repeating yourself, and address all the points you need to. Outlining shouldn’t take you more than five to six minutes, and will save you time in the long run.


Creating an outline for the analytical writing assessment is a good way to save time and improve your essay.
Creating an outline for the analytical writing assessment is a good way to save time and improve your essay.


The Final Word: Avoiding Common GMAT Mistakes

The GMAT can seem like a minefield of potential mistakes. But with the tips we’ve gone over, you can avoid the most common traps that GMAT test-takers fall into.

As you prep for the GMAT, study effectively: make a detailed study plan, stick to a schedule, and target your weaknesses. Use the best resources you can find, and familiarize yourself with the GMAT format.

When you take the exam, don’t be afraid to guess. Keep track of your timing, as it’s in your best interest to get through every section fully. Also, to avoid careless mistakes, pay close attention to what every question is asking you to do.

Finally, make sure you understand the GMAT format inside and out before you step into the testing center. Develop a strategy for every question type that you can use on every practice test and on the official GMAT. Feeling prepared for anything you encounter on exam day is the best way to avoid common GMAT mistakes.


What’s Next?

For more GMAT prep and test-taking strategies, check out our 10 expert tips on how to beat the GMAT.

Looking for additional section-specific guides? Our articles on GMAT grammar rules and the GMAT quant section will help you hone in on the section you find most challenging.

If you struggle with timing, our 9 expert tips on getting through every question on the GMAT will help.

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Author: Laura Dorwart

Laura Dorwart is a Ph.D. student at UC San Diego. She has taught and tutored hundreds of students in standardized testing, literature, and writing.