Why Practice Test Scores Vary

I recently took a practice test and it was much lower than my other practice tests. I’ve been studying for awhile now, and I am freaking out a little bit. Shouldn’t I be improving. Here are the scores from my practice tests.

Practice test 1: 580
Practice test 2: 620
Practice test 3: 590
Practice test 4: 550

What happened? Can you help me improve? I don’t want this to happen when I take the test.

This is a common question that we encounter at Magoosh—a student is taking practice tests and their scores are all over the place. Shouldn’t there be some trend, like going up, after lots of practice. But this is not the case. Why?

You may be surprised that statistical variation is common and happens for a number of reasons. Let’s explore some of the reasons for this variation.

Different Practice Tests
The most obvious reason for a score difference is using practice tests from a different companies. Each test prep company creates questions of varying quality. And this quality affects students scores. Poorly created questions, like you might see in a Princeton Review, will not give you an accurate prediction of your score. Whereas, a Manhattan practice test will have better questions with less mistakes, making it a more accurate assessment, but not a perfect assessment (I hear grumblings in forums about inflated verbal scores on Manhattan tests).

But it doesn’t end here. We also have to think about how test prep companies calculate your estimated score at the end of the test. No company knows exactly what the GAMC does to convert a raw score into a scaled score. As such, each company has to approximate this conversion, and each company does something slightly different. Since this is not standardized across practice tests, you can definitely expect to see variations in the scaled score from test to test.

If you want the best prediction of your score on the test, I recommend taking a practice test made by the same people who make the GMAT—GMAT Prep.

Different Testing Environment
Environments exert a powerful influence over us. If you take the same test twice, but change the testing environment, you can expect to see a difference in scores. The difference between sitting in your room and going to a private study room at the local library to take a practice test is dramatic. One spot is obviously more ideal than the other. And by “ideal,” I mean that it is more like the testing environment for the test. Did you vary your testing environment? Was your low score from the test you took while in a cafe? Look no further. You found the culprit then. Make sure that you emulate the testing environment that you will see on test day.

Different Diet
What you put, or don’t put, into your body matters. Think back to what you ate in the 24 hours leading up to your practice test. Was your belly full of sweets or junk food? Did you skip a meal? Did you indulge in delectable southern BBQ? That might have been the difference. To optimize your score and your ability to succeed, you need to eat well. And not just before the test, but all the time. You need to give your brain the food it needs. Eat fish, almonds, avocados, garlic, and blueberries.

Different Sleep Patterns
Erratic and irregular sleep patterns are detrimental to learning and performance. Researchers at UC Berkeley have shown that a consistent eight hours of sleep is an important part of learning. Not only will it boost your focus and performance, but it will also keep you positive and foster emotional health. Make it a point to sleep enough before your test. And if you want all those daytime hours of studying to really make a difference, you need to get plenty of sleep in the weeks leading up to the test.

Takeaway
Variation in practice test scores is normal and expected. Many factors affect the predicted score you receive on a practice test. Ultimately, don’t invest too much in the estimated scores. Remember that it is only a predication and not necessarily accurate. Use practice tests as a way to simulate the test, not as a untainted measure of your GMAT score.

More from Magoosh:
How to Calculate GMAT Scores
How Hard is the GMAT
What's a Good GMAT Score
How Long Should I Study for the GMAT