When talking to my students about their study plans to prepare for the GMAT, I always emphasize the need to take as many computer-adaptive practice tests as possible. A test-taker needs to experience what the real GMAT is like, and there’s no better way to do that than to sit for four straight hours and experience the challenge (and joy?!) of facing progressively difficult questions.
When students begin preparing for the GMAT, I always recommend that they take a GMATPrep practice test early in their studies. I do this for several reasons:
This is the last installment of an FAQ series on Computer-Adaptive Tests (CAT). Check out part 1 and part 2 as well.
You can be in the 99th percentile overall even if you didn’t score in the 99th percentile on either of the sections, because the overall score is calculated separately from the section scores and their percentiles. So, for example, you could get a 48 on Quantitative (86th percentile), a 45 on Verbal (98th percentile), and a 760 overall (99th percentile).
This is a follow to my last piece, CAT FAQ: Beginner.
Most exams are linear assessments, like the SAT or your 10th grade history final. These are scored by counting the number of questions you answer correctly, and sometimes by penalizing for each question you answer incorrectly. The result, a raw score, is then converted to a scaled score, like the 600-2400 range for the SAT.
A computer-adaptive test (CAT) works very differently. It doesn’t really care as much about how many you get right or wrong, but rather which questions you get right and wrong. The CAT algorithm estimates your ability based on a variety of criteria, including the difficulty of a question. After each question, it evaluates your response and updates this estimate. When the test is over, the algorithm converts your quantitative and verbal ability estimates into the quantitative and verbal scaled scores, and then separately combines your quantitative and verbal ability estimates to calculate the overall score.
I’ve received a number of inquiries from the community about the GMAT algorithm, so I thought it best to reply in article form.
An algorithm, generally, is a usually efficient set of well-defined steps the following of which results in the solution to some pre-defined problem. In the case of a CAT algorithm, the problem is to reliably and efficiently estimate a student’s ability in a reasonable amount of time. Some CAT algorithms seek to solve this problem by selecting one question at a time, each subsequent question selected based on all of the student’s prior responses. Other algorithms look only at the most recently-answered question. Still others evaluate responses to specific groups of questions. CAT algorithms also vary with regard to the explicit criteria they use to select the next question (or sets of questions) to administer. Some try to minimize total measurement error. Others try to maximize the precision and accuracy of measurement for each question administered. Still others try to select questions that will most refine the current ability estimate. As a consequence, CAT algorithms can vary greatly from one another, depending on the specific implementation of the algorithm, and the intent of the algorithm developers.
It’s essential to prepare for the GMAT with full-length computer adaptive tests (CATs), because the CAT format has lots of unique features (for example, the importance of skipped questions). Bottom line: you need to get your hands on some CATs and make sure that you practice wisely with them, because they are a relatively scarce resource.
FACT: So many students get caught up in the idea that one must solve a problem to get the correct answer. Well that is not the case for many questions on the GMAT. Sometimes it actually slows you down to fully work out a problem.
Let’s go to the board to check out my point with DATA SUFFICIENCY.
It’s really weird taking a test on a computer. Processing the ones and zeros on the screen requires extra mental effort on your part. Many people now taking the GMAT go in having only experienced paper-based standardized tests. Additionally, the GMAT may well be your first experience working on a computer under strict time constraints.
One of the biggest frustrations of taking a CAT test is that you don’t have the questions and answers right there in front of you. Without the luxury of being able to write notes, eliminate answers, make equations or draw pictures, I am certain that you will find this extremely annoying in a CAT environment. Some of the following might sound like common sense, but not everyone employs these useful strategies that will save you valuable time come test day
The CAT test format can be frustrating, and time consuming, for many reasons, but there are some tricks that I found useful when taking the test that seemed to help me out.
The GMAT is a CAT, or a Computer-Adaptive Test. But on some sections, the computer is less an assistance than a hindrance. The older you are, the more likely it is that you spent your childhood, teen years, and even adulthood learning how to read in a paper-based world. Standardized testing, especially reading comprehension, is very different on a paper-based test than it is on a CAT. Years of paper-based reading trains the test-taker to take notes on the passage itself, underlining significant sections of the passage and putting notes in the margins near the relevant text. On a CAT, you don’t have that luxury. But learning to read actively even without the benefit of marking up the text is key to improving your reading comp score. Here are a few ways to do that.
We’ve received grades all our lives. In fact, we’re so used to them that we often don’t think very much about what they mean, or how they are calculated. So today we’re going to look at some of the different ways in which tests are scored, and at what those scores mean.
There are several general ways the makers of the test can increase the level of difficulty of any given passage. Before examining the specific elements that the test makers like to test, reviewing the general methods that can be used to increase difficulty is helpful.
The following five methods are the primary ways used by the test makers to alter the perception of difficulty that students have about individual passages:
Your overall score out of 800 results from your performances in quant and verbal, each of which is first scored independently on a scale of 0-60*. These subscores are then combined to yield your overall score according to formulae to which only GMAC and ACT (the organizations that own and write the GMAT, respectively) are privy. Each subscore (verbal and quant) receives a percentile ranking as well. This indicates the percentage of test-takers who scored below your level over the past few years. So, for example, if you receive a verbal subscore of 40, you are in the 89th percentile, which means that 89% of all test-takers did not perform as well as you in verbal.
This is the first in a series of common student questions that I’ll be answering here on BTG. This is one we hear a lot — I just had a bad day; I’ll take it again soon and make sure to focus next time. If the GMAT were really that susceptible to luck, it wouldn’t be a very good yardstick by which to compare individuals with limited data points. So, how big a role does luck play?
