Should I Guess on the SAT?

In my first SAT tutoring session with a new student, there are two questions I always ask:

  1. What do you know about the SAT "guessing penalty"?
  2. Should you guess on the SAT?

The range of answers that I receive is wider than a California freeway. There are a lot of conceptions--most of them misconceptions--out there about guessing on the SAT. So what's the deal? How does the SAT scoring system work? And as a student taking the test, how does that affect you? Should you never guess? Should you always guess, even if that means just filling in a random bubble?

The SAT Scoring System

Let's start with the SAT scoring system. It is designed so that a student who fills in every bubble randomly will score approximately the same as a student who leaves the entire test blank. The purpose is so students cannot improve their scores through completely random guessing. However, it is also designed so that random guessing does not hurt students' scores.

Here's how it works:

  • Correct answer: 1 point
  • Blank answer: 0 points
  • Incorrect answer: -0.25 points

Here's an example to see how it could affect an actual test taker:

  • First, let’s pretend that you are taking a test that does NOT have a guessing penalty, like the ACT. You have 10 questions remaining in the section. You look at the clock to see that the section is going to end any second. You quickly fill in a bubble for each of the last 10 questions. Assuming each question on this test has 5 answer choices (like the SAT), your chance of randomly guessing the correct answer is 1 out of 5. 1/5 x 10 questions = 2. This means that you can expect to get approximately 2 of the 10 questions correct by guessing randomly. These are essentially 2 free points. You didn’t even look at these questions, yet you still got 2 of them correct. The SAT guessing penalty is designed to eliminate these free points.
  • Now, let’s suppose you are in the same situation on the SAT: 10 questions remaining, time about to expire.
    • If you leave all the questions blank, you will get 0 points.
    • If you guess randomly, we can expect that you will get approximately 2 questions correct and 8 questions wrong. For your 2 correct answers, you will receive 2 points. For each of your 8 wrong answers, you will get lose ¼ point. -¼ point x 8 = -2 points. So you will gain 2 points for your correct answers, lose 2 points for your wrong ones, and end up with 0 points--the same score you would have received if you had left all the questions blank.

Remember, these are all approximations based on statistical averages. (The chance of getting heads when you flip a coin is ½, but that doesn't mean flipping a coin twice guarantees 1 heads and 1 tails.) A student in the situations above could get lucky and correctly guess 5 of the 10 answers or unlucky and guess incorrectly on all 10.

Should You Guess?

So you now know how the SAT scoring system works. But how should that affect your test taking strategy?

First, recognize that every student is unique. When I work with students, I design a customized approach to guessing and skipping questions for each student, depending on their scoring level, strengths and weaknesses, speed within each section, performance on easy vs. difficult questions, and ability to eliminate. There is a lot of variation. But that shouldn't stop us from covering one major rule that applies to any student:

Guessing Rule: If you can confidently eliminate 1 answer choice, you should always guess. And if you can eliminate more than 1, then it is even more critical that you guess!

There is statistical logic to support this rule. Let's start with the same example as above: 10 questions left in the SAT section. But this time, instead of guessing randomly from the 5 answer choices, let’s say you are able to eliminate 1 answer choice from each question. Of the 4 remaining choices, you still have no clue and have to guess completely randomly. However, because of your elimination, your odds of randomly guessing each correct answer are 1 out of 4 instead of 1 out of 5. Now, on average, you will get 2.5 of the 10 questions correct (for 2.5 points) and 7.5 wrong (for -1.875 points), leaving you with an average result of 0.625 points. It may not sound like a lot, but 0.625 is definitely better than 0. If you can eliminate more than one answer choice, your expected amount of points will increase even more.

So, for the one remaining question, what should you do if you can't eliminate any answer choices? Or if you're running out of time, should you bubble in randomly? Statistically, it doesn't matter. If you're feeling conservative, leave it blank. If you're a risk taker, go ahead and guess. You might just get lucky.