According to the National Center for Education Statistics, about 1.5 million students took the standardized ACT exam in academic years 2009-10, and the number of students taking the test has steadily increased every year since 1996. Unlike the SAT, the ACT is an achievement test that measures the information you've learned in school, and some students find that they score better on this test than on the SAT. However, the test is timed, and failing to complete the test can hurt your scores.

ACT Scoring

Your ACT score is based on a raw score, which is the number of questions you answered correctly. You'll get one point for each question you answer correctly, and unlike the SAT, there's no penalty for guessing on the ACT. This means it's better to fill in an answer that could be wrong than leave a question blank, and not completing the ACT will always harm your score. Your test score -- which is a calculation based upon your raw score -- will range from one to 36 for each test section.

Effect on Score

The effect of not completing the test depends on how much of the test you leave blank and how many of the answers you would have answered correctly. If you leave just one or two answers blank, the effect on your score will be negligible and, if you wouldn't have gotten the answers right anyway, won't affect your score at all. But if you leave many answers blank, you could see a serious dip in your score. Even if you guess, the odds are good that your guesses will be right on at least a few answers.

Increasing Speed

To increase your odds of completing the test, take several timed practice tests before test day. If you find you're struggling with a question, move on to the next question, and return to the harder question when you've completed the easier questions. Reading a question carefully the first time and eliminating obviously incorrect answers can help you complete each section more quickly. Students with disabilities such as attention deficit-hyperactivity disorder and learning disorders can receive accommodations for longer testing times, so if you have a learning disability, contact the ACT and ask about accommodations to increase the odds that you'll complete the test.

Filling in Answers

If you find you only have a minute or two left, you're better off filling in guesses than leaving the test blank. As you take the test, cross out answers you know are wrong. This narrows your options for guessing and increases the likelihood that some of your guesses might be correct.