Common ACT Mistakes

If I had a nickel for every time a student hit his or her forehead and exclaimed, “Aaah! That was a stupid mistake!” I’d have….a lot of nickels.


Preferably handed to me by a tiny mouse.

Unlike this tiny mouse, making mistakes on the ACT is not so cute. Nothing is more frustrating than knowing you could have correctly solved a problem, but instead made a silly error and lost that opportunity.

Here are some of the most common mistakes students make on the ACT so you can be on guard.

On the Test Overall


Most students struggle with time on at least one section of the ACT. Rushing to get to every single question is not necessarily a good idea if you are making careless mistakes along the way. Focusing all of your attention on only three-quarters of the questions, or even two-thirds, may in fact get you your best score.

Not bubbling in answers for everything.

There’s no penalty for guessing on the ACT, so it’s a real shame to not get some points for lucky guesses.

On the ACT English Test

Avoiding “No Change.”

Some students think answer choices like “No change” or “No error” are traps, but this is not true, particularly on the ACT English section. The vast majority of questions have “No change” as a potential answer, and it is just as likely to be correct as any other answer choice.

Not reading the entire sentence.

The ACT often asks a question about one small part of a really long, complex sentence. Make sure to read your answer choice into the entire sentence–there may be a punctuation mark that doesn’t work with your answer, or your answer may inadvertently create redundancy or a sentence fragment.

Answering questions on the entire passage or paragraph too soon.

Sometimes questions that pertain to a whole paragraph or passage appear before you’ve gotten through the entire thing. Skip these questions and save them for last once you have read everything.


Not answering the right question.

It’s easy to get caught up in calculations and forget that the question asked you to find the value of 2y instead of y. Circle what the question is asking for and double-check before you answer.

Not using your calculator enough.

You are allowed to use a calculator, so use it for all but the simplest calculations. It’s easy to make a mistake dividing 84 by 6 with long division; you are less likely to do that on a calculator. If you have a graphing calculator, you can also use the graphing function to solve some coordinate geometry problems or the sin, cos, tan buttons to solve trig problems.

Not writing down your work.

If you are using hypothetical numbers to help solve a word problem, make sure to write down the numbers you are using. The last thing you want to do is get to your solution and forget the original numbers you had used. Or if you are plugging negative numbers into an algebra equation, make sure to use parentheses so you don’t forget about the signs. For example, if you know x = -6 and y = 14 – x, write y = 14 – (-6).


Inferring too much.

The ACT is very literal. Most of the answers will be directly stated in the passage. If they aren’t, then the ACT only wants you to make teeny tiny inferences, not grand leaps in thinking. If you find yourself rationalizing how an answer could be true, stop. You’re going down the wrong path.

Not noticing transitions.

If there is a change in perspective or a new counterargument or direction introduced, the ACT will almost always ask you about it, so note those transition words and phrases.

Answering questions in order.

The Reading questions are all mixed together. If you can’t figure out the answer to one, skip it and come back to it after you answer the others on the same passage; you may stumble upon the answer as you work through the other questions.


Mixing up labels and data.

The ACT Science test will often give you multiple charts, diagrams, and figures that include the same or similar information. Always make sure you are looking at the right table or the right line on a line graph.

Not noticing NOT and EXCEPT in the questions.

Sometimes it seems like putting words in all caps is a signal for your brain to ignore them rather than notice them. When you see “NOT” or “EXCEPT” in a question, circle it, draw arrows to it, whatever it takes for you to remember you are looking for what doesn’t fit, not what does.


Not addressing all three perspectives.

You have to address all three perspectives; the prompt says so. If you don’t, you will lose quite a few points.

Not having an argument.

It’s easy to focus too much on the analyzing the perspectives part and forget that the most important thing is that you present your own perspective. This means that you need to have a thesis statement and you should be supporting it throughout. Your thesis needs to present an argument. (A good test is to ask yourself if someone could disagree with your argument. If not, it’s not an arguable thesis.)

Straying too far from the question

The ACT essay question always gives you the option to “present a different point of view” on the topic. For all but the strongest writers, I strongly advise against this. It’s too easy for you to go off-topic, which will get you a very low score. Stick with agreeing with one of the provided perspectives.


  • Kristin Fracchia

    Dr. Kristin Fracchia has over fifteen years of expertise in college and graduate school admissions and with a variety of standardized tests, including the ACT, SAT, GRE, GMAT, and LSAT, with several 99% scores. She had a PhD from the University of California, Irvine, an MA degree from The Catholic University, and BA degrees in Secondary Education and English Literature from the University of Maryland, College Park. She was the recipient of the 2013 Excellence in Teaching Award and the Chancellor’s Club Fellowship from the University of California, Irvine. She’s worked as a high school teacher and university professor, as an independent college and graduate school admissions counselor, and as an expert tutor for standardized tests, helping hundreds of students gain acceptance into premier national and international institutions. She now develops accessible and effective edtech products for Magoosh. Her free online content and YouTube videos providing test prep and college admissions advice have received over 6 million views in over 125 countries. Kristin is an advocate for improving access to education: you can check out her TEDx talk on the topic. Follow Kristin on LinkedIn!

By the way, Magoosh can help you study for both the SAT and ACT exams. Click here to learn more!

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