Avoiding the C-Trap in Data Sufficiency
Have you heard of the C-Trap? I’m not going to tell you what it is yet. Try this problem from GMATPrep® first and see whether you can avoid it
* “In a certain year, the difference between Mary’s and Jim’s annual salaries was twice the difference between Mary’s and Kate’s annual salaries. If Mary’s annual salary was the highest of the 3 people, what was the average (arithmetic mean) annual salary of the 3 people that year?
“(1) Jim’s annual salary was $30,000 that year.
“(2) Kate’s annual salary was $40,000 that year.”
I’m going to do something I normally never do at this point in an article: I’m going to tell you the correct answer. I’m not going to type the letter, though, so that your eye won’t inadvertently catch it while you’re still working on the problem. The correct answer is the second of the five data sufficiency answer choices.
How did you do? Did you pick that one? Or did you pick the trap answer, the third one?
Here’s where the C-Trap gets its name: on some questions, using the two statements together will be sufficient to answer the question. The trap is that using just one statement alone will also get you there—so you can’t pick answer (C), which says that neither statement alone works.
In the trickiest C-Traps, the two statements look almost the same (as they do in this problem), and the first one doesn’t work. You’re predisposed, then, to assume that the second statement, which seemingly supplies the “same” kind of information, also won’t work. Therefore, you don’t vet the second statement thoroughly enough before dismissing it—and you’ve just fallen into the trap.
How can you dig yourself out? First of all, just because two statements look similar, don’t assume that they either both work or both don’t. The test writers are really good at setting traps, so assume nothing.
Read more
My GMAT Score Dropped! Figuring Out What Went Wrong
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I’m reviving an old article I first wrote five years ago (time flies!) because the topic is so important. I hope that no one ever again experiences a significant GMAT score drop on the real test (or even a practice one!), but the reality is that this does happen. The big question: now what? Read more
When is it Time to Guess on Quant?
So you’ve been told over and over that guessing is an important part of the GMAT. But knowing you’re supposed to guess and knowing when you’re supposed to guess are two very different things. Here are a few guidelines for how to decide when to guess.
But first, know that there are two kinds of guesses: random guesses and educated guesses. Both have their place on the GMAT. Random guesses are best for the questions that are so tough, that you don’t even know where to get started. Educated guesses, on the other hand, are useful when you’ve made at least some progress, but aren’t going to get all the way to an answer in time.
Here are a few different scenarios that should end in a guess.
Scenario 1: I’ve read the question twice, and I have no idea what it’s asking.
This one is pretty straightforward. Don’t worry about whether the question is objectively easy or difficult. If it’s too hard for you, it’s not worth doing. In fact, it’s so not worth doing that it’s not even worth your time narrowing down answer choices to make an educated guess. In fact, if it’s that difficult, it may even be better for you to get it wrong!
To make the most of your random guesses, you should use the same answer choice every time. The difference is slight, but it does up your odds of getting some of these random guess right.
Scenario 2: I had a plan, but I hit a wall.
Often, when this happens, you haven’t yet spent 2 minutes on the problem. So why guess? Maybe now you have a better plan for how to get to the answer. I know this is hard to hear, but don’t do it! To stay on pace for the entire section, you have to stay disciplined and that means that you only have one chance to get each question right.
The good news is that no 1 question you get wrong will kill your score. But, 1 question can really hurt your score if you spend too long on it! Once you realize that your plan didn’t work, it’s time to make an educated guess. You’ve already spent more than a minute on this question (hopefully not more than 2!), and you probably have some sense of which answers are more likely to be right. Take another 15 seconds (no more!) and make your best educated guess.
Scenario 3: I got an answer, but it doesn’t match any of the answer choices.
This is another painful one, but it’s an almost identical situation to Scenario 2. It means you either made a calculation error somewhere along the way, or you set the problem up incorrectly to begin with. In an untimed setting, both of these problems would have the same solution: go back over your work and find the mistake. On the GMAT, however, that process is too time-consuming. Plus, even once you find your mistake, you still have to redo all the work!
Once again, though it might hurt, it’s still in your best interest to let the question go. If you can narrow down the answer choices, great (though don’t spend longer than 15 or 20 seconds doing so). If not, don’t worry about it. Just make a random guess and vow to be more careful on the next one (and all the rest after that!).
Scenario 4: I checked my pacing chart and I’m more than 2 minutes behind.
Pacing problems are best dealt with early. If you’re more than 2 minutes behind, don’t wait until another 5 questions have passed and you realize you’re 5 minutes behind. At this point, you want to find a question in the next 5 that you can guess randomly on. The quicker you can identify a good candidate to skip, the more time you can make up.
This is another scenario where random guessing is best. Educated guessing takes time, and we’re trying to save as much time as possible. Look for questions that take a long time to read, or that deal with topics you’re not as strong in, but most importantly, just make the decision and pick up the time.
Wrap Up
Remember, this test is not like high school exams; it’s not designed to have every question answered. This test is about consistency on questions you know how to do. Knowing when to get out of a question is one of the most fundamental parts of a good score. The better you are at limiting time spent on really difficult questions, the more time you have to answer questions you know how to do.
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What do you want to get wrong on the GMAT?
Right now, you might be thinking, “Wait, what? I don’t actively want to get stuff wrong!”
In fact, yes, you do. Let me take you on what might seem like a tangent for a moment.
Would you agree that one of the marks of a strong business person is the ability to tell the difference between good opportunities and bad ones? And the ability to capitalize on those good opportunities while letting the bad ones go?
Yes, of course—that’s a basic definition of business. What does that have to do with the GMAT?
The GMAT is a test of your business skills. They don’t really care how great you are with geometry or whether you know every obscure grammar rule in the book. They care whether you can distinguish between good and bad opportunities and whether you can drop the bad ones without a backward glance.
If you want to maximize your score on the GMAT, then you will have a short-list of topics that you want to get wrong fast on the test. My top three in math are combinatorics, 3-D geometry, and anything with roman numerals.
How do you decide what your categories should be? Let’s talk.
But I don’t really want to get stuff wrong… that’s just a metaphor, right?
No, it’s not a metaphor. I really want you to plan how and what you’re going to get wrong! If you haven’t already, read my post about what the GMAT really tests. (You can go ahead and read it right now; I’ll wait.)
In a nutshell, the GMAT is set up to force us to get some of the questions wrong. No matter what you can do, they’ll just give you something harder.
Ultimately, they want to see whether you have the makings of a good business person. One way to test that is to force you into a situation where your choice is between spending extra time and mental energy on something that’s too hard—likely causing yourself to run out of time and energy before the test is over—and cutting yourself off when appropriate.
How do I cut myself off?
First of all, put yourself in this mindset:
You’re at the office, working on a group project.
A colleague of yours is the project manager.
The manager annoys you because he (or she) keeps assigning too many tasks, some of which are not all that important.
Sometimes, you’re rolling your eyes when your colleague tosses a certain piece of work at you; you’re thinking, “Seriously, the client meeting is in 3 days. This is NOT the best use of our remaining time.”
Got that? Okay, now during the test, put yourself in that mindset. The test itself is your annoying colleague. When he drops a roman numeral question in your lap, or a 4-line sentence correction with every last word underlined, you’re already rolling your eyes and thinking, “Are you serious? Come on.”
Here’s the key step: let yourself get just a little annoyed—but with the test, not yourself. You’re not feeling badly that you don’t like the problem; you don’t feel as though you’re falling short. No way! Instead, your colleague is trying to get you to do something that is clearly a waste of time. Roll your eyes. To appease your colleague, figure out whether there’s enough here for you to make an educated guess. Then pick something and move on to more important tasks.
How do I know when to cut myself off?
Quick: name your top three annoyances in quant. Now do the same in verbal. Here’s another one of mine: an RC detail EXCEPT question on a really technical topic with very long answer choices. (In other words, I have to find the four wrong answers in order to find the one right answer… and the topic area is very long and annoying.)
That’s your starting point: you already know you dread these areas. Back this up with data: make sure that these really are the worst ones for you. “Worst” is defined as “I rarely get these right and even when I do, I still use too much time and brain energy.”
Next, check to see how commonly tested the particular topic or question type is. You can’t afford to blow off algebra—that’s too broad a topic. You can, though, blow off sequences.
For some topics, you do want to try to be able to answer lower-level questions. For instance, if one of my students just hates polygons (triangles, squares, rectangles), he has my blessing to blow off harder questions—the ones that combine shapes, for example, or that move into the 3-D arena. He does need to learn the more basic formulas, though, so that he isn’t missing too many lower-level questions.
Your particular mix of pet peeves will almost certainly change over time. Initially, I had some other things at the top of my list, such as weighted averages. Then, I discovered a much better way to do those problems, so 3-D geometry took its place.
Some topics, though, will always be weaknesses. I’ve never liked combinatorics and doubt I ever will. That’s perfectly fine, particularly when the topic is not that commonly tested anyway!
Sound off in the comments below: what areas do you hate the most? Your new strategy is to get those wrong fast and redirect that time and mental energy elsewhere!
4 Steps to Get the Most out of your CATs (part 2)
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Last week, we talked about the first two elements of getting the most out of your CATs.
#1: How NOT to use your practice CATs
#2: How to analyze your strengths and weaknesses with respect to timing
This week, we’re going to dive even further into strengths and weaknesses using the Assessment Reports.
#3: Run the reports.
New Year’s Resolution: Get Your GMAT Score! (Part 1)
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Whether you’ve been studying for a while or are just getting started, let’s use the New Year as an opportunity to establish or renew your commitment to getting your desired GMAT score. Read more
Test your Critical Reasoning Skills: Are Top GMAT Scorers Less Ethical?
Some interesting —and alarming—articles have been making the rounds lately, following on the heels of an academic study published by professors at the University of Akron and Cleveland State University. The more reputable articles report such sweeping conclusions that I actually wondered whether the journalists got it wrong, so I went to the source (I can link only to the abstract here, but I did read the full study).
When I read the study’s methodology, I knew I had my next article topic. We’re going to test our Critical Reasoning (CR) skills on an actual academic study! You might have to do something similar in business school (admittedly with a business case, not an academic study), so let’s test your b-school readiness now!
(Note: I refer to the “more reputable articles” because some blogs have picked this up and publishing under headlines such as “Is the GMAT the root of all evil?” As much as you may hate studying for this test, I think we can agree that this characterization is a bit over the top. : ) )
Correlation vs. Causation
We need to define a couple of terms first. You may already have learned about correlation and causation in your CR studies; here’s a refresher.
Correlation: two phenomena tend to occur or appear at the same time or in conjunction with one another
Causation: one phenomenon causes another phenomenon
Correlation does not imply causation. One of two correlated phenomena could cause the other but those two things could also have absolutely no causation between them. Alternatively, the two things could both be caused by a third thing. The two things could even cause each other! (Predator-prey dynamics are an example of this kind of two-way dependency.)
For example, have you ever noticed how, when the ground is wet, people often seem to be carrying around umbrellas? Those two phenomena are correlated. Which one causes the other? Read more
Just Chillin’ @ the Bar
When under pressure, do you tend to sit back and assess the situation in a thoughtful way, or do you instead recall everything you know and start jotting down formulae such as W=RT on your scratch paper? If you have a tendency for the latter, this blog post is for you.
I’ve recently had a few tutoring students who all suffered from the same issue: they try a problem in a relaxed state and can easily solve it, sometimes without even putting pen to paper… But when they are in the midst of a practice test (and even more so in a real test) they can see the same problem and spend 4 minutes on it, with a lot of messy algebra, and often times they just give up and move on (the right thing to do under that circumstance!).
The Quant section of the GMAT may feel like a math test, but I assure you it is not. It is a cleverly designed assessment of your thinking faculties, and if you turn on ‘autopilot’ you are no longer thinking. In order to succeed on this test, you have to think your way through each problem.
When I take the GMAT, I imagine that I’m hanging out with my buddies at the bar – we’re telling each other jokes and sharing brain teasers. Here’s how it works: you’re all just out having a good time, there’s no pressure, maybe you’ve had a couple of drinks so you only try to solve those brain teasers that you think you can solve in 2-3 minutes or less. If the brain teaser seems too hard, you just give up (and no-one will think less of you!)
I suspect that your approach to the following problem would be completely different if your mindset is a ‘bar’ mindset vs. an ‘autopilot’ mindset:
I’m driving at a constant speed and it took me 4 hours to finish the first 1/3 of my trip. How long will it take me to complete the rest of the trip if I double my speed?
GMAT Percentiles Update
Last week, GMAC updated its percentiles for GMAT scores. The organization does this once a year to smooth out any differences in the testing pool.
What do I mean by “differences?” The demographics of the people taking the exam change over time. In particular, over the last ten years or so, GMAC has seen a huge increase in the number of non-United-States-based students taking the test. A majority of these students speak English as a second (or third!) language; a majority also have a better grounding in quantitative skills than the average U.S.-educated student. These differences lead to changes in the data over time.
Scaled Scores vs. Percentiles
GMAT results are reported using various “scaled scores.” We receive a 2-digit score for quant, a separate 2-digit score for verbal, a Q+V-combined 3-digit score, and two more separate scores for the essay and IR sections.
Think of these scaled scores as “skill levels.” They reflect a specific, measurable level of ability. Here’s the interesting thing: the skills needed to reach a certain level do not change over time. A quant score of 45 today reflects the same skill level as a quant score of 45 earned ten or even twenty years ago.
What does change over time is the percentile ranking associated with that score. A percentile ranking reflects how much better you did than a certain percentage of the test-taking population. For example, if you score in the 75th percentile, then you scored better than 75% of the people taking the test—not just that day, or that week, but for the past couple of years (or whatever timeframe is designated for that test).
Imagine that you give a math test to a bunch of 10-year-olds. The scoring algorithm is very simple: if you get a question right, you get one point. You then gather all of the scores and figure out percentile rankings for that group. Let’s say that a certain score (let’s call it 5) represents the 50th percentile. A student who scores 5 earned a better score than 50% of her peers.
Then you take that exact test and give it to a bunch of 14-year-olds. They’re a lot better at math. The same score of 5 might represent only the 25th percentile for this new group, because more of these students have better math skills and can answer more questions correctly. A score of 5 still means the same thing (in this case, 5 questions right), but the pool of testers has changed and so the percentile rankings change too.
This is essentially what happens with the GMAT over time as well. If more people who are good at math start taking the test, then that score of 45 (which represents a certain, fixed level of skill) will drop in the percentile rankings because more people will be capable of performing at that level or higher.
We’ve seen especially big demographic changes on the GMAT over the last 5 to 10 years. In 2006, a quant score of 45 was rated the 78th percentile. Someone scoring at that level had better quant skills than 78% of the people taking the exam around that time.
Today, that same skill level of 45 rates the 66th percentile. This does not mean that someone scoring a 45 today is worse at math than someone with the same score in 2006; rather, the two students are equally good. Instead, a greater percentage of the population taking the test today has stronger math skills.
You might be thinking: oh, great. So that means I have to do even better at math. Actually, the opposite is (sort of) true. Keep reading.
This Year’s Trends
Paranoia Runs Deep, Into Your Heart It Will Creep
I know what Statement 2 is telling me; it’s saying ˜Become a carpenter!’
Why is this question here? Why am I here? When’s the civil service exam? Garbage men still have a union. . .
Have you lived that movie? Paranoia is only human and the old saying is true: Just because you’re paranoid doesn’t mean they’re not out to get you. Paranoia is a primal reaction, developed to help protect humans from animals with sharp, pointy teeth. Unfortunately, it is not helpful when one is facing questions with sharp, pointy teeth. Even though the GMAT is out to get you. Failing to control your paranoia is a hidden reason for underperforming on the actual exam.
On this blog, I and others have discussed many factors crucial for success: foundation skills, strategies, timing, precision, and so forth. And it’s like I say about L.A.—everything you ever read [here] about it is true. However, after honing these skills, after achieving mastery, too many test takers succumb to their paranoia and thus revert when taking the actual exam, especially for the first time. Even 99th percentile skills will crumble if undermined by irrational panic and the results will not be gratifying. (Have you ever watched the Chicago Cubs play a post season series?) To succeed, folks must understand the difference between dispassionate, objective analysis—I’ve never gotten a combinatrics question right in life, why do I think I’ll have a divine inspiration today?—and irrelevant fear—They’re going to tattoo a scarlet L on my forehead. Just as folks plan question and timing strategies, they must develop tools to banish their internally generated negative visualizations.
How do you tell the difference? Objective analysis responds to the stimuli on the monitor. Paranoia is a response to internal doubts. (Notice how this is parallel to the nature of the exam—search for the answer on the screen, not in the opinions in your head.) Sometimes, after you’ve read a question twice (everyone has a sinking feeling the first time), you hear yourself singing, I’ve got the ˜I don’t know where I’m going but I’m going nowhere in a hurry’ blues. That’s the truth, not paranoia. Bail out. As one of my acting coaches used to say, Only schizophrenics don’t react to the reality around them. Conversely, paranoia is when your thoughts of impending disaster revolve around your supposed shortcomings rather than the material on the screen. As I’ve said before, if while taking the exam you find yourself thinking about how big a dumb ass you are, check the question—if it doesn’t read, Which of the following best describes how big a dumb ass you are?, you’re thinking about the wrong thing. That is paranoia. No kidding—you knew that.
Well then, why do people recognize the difference between analysis and paranoia but still succumb to the latter? Because they try to do the impossible. They try not to have thoughts of failure. That’s impossible—you can’t override human nature. I have feelings of paranoia, even though I’ve always scored in the 99th percentile. I still have them”even though I don’t really care about my score anymore. Instead, you have to recognize irrationality in yourself and laugh it off. I say to myself, Save some of that craziness for menopause. Then I giggle, read the question again, and really listen to the words. And if I still don’t get it, I say, Screw them if they can’t take a joke. And bail out.
Maybe some of you can’t make jokes to yourself during the exam because you’re worried about your entire future. That’s part of the problem—if a chunk (or all) of your mind is thinking about things other than the words on the monitor, it will lower your score. It’s the difference between worrying about being the hero or the goat and just seeing the ball and hitting the ball. Feelings of failure while taking the exam are like stage fright. That’s what stage fright is—standing up there thinking you look like an idiot. You say, No, it’s much different—they give me a piece of paper that says I’m an idiot. No. Really. It’s the same. So, I’ve got another suggestion for you, if you didn’t like the first one.