Spotting Common Critical Reasoning Flaws on the GMAT
This is the least frequently tested of the 5 Assumption Family question types, so you can ignore this type if you aren’t looking for an extra-high score. If you do want an 85th+ percentile verbal score, though, then you have to make sure you know how to tackle Flaw questions.
Flaw questions on the GMAT follow predictable patterns: the flaw always in some way addresses either how the evidence is being interpreted to lead to the conclusion, or how the evidence was obtained.
Let’s take a look at a few specific examples of common GMAT flaws.
Real Numbers v. Percentages
There are actually two major flaws here, and we’ll look at the one that ISN’T the title of this sub-section first, just to get it out of the way: the evidence isn’t sufficient to support the conclusion. The conclusion is about the “interest” of executives in “programs that promote leave options for personal reasons,” but the evidence only discusses percentages of executives who were involved in one specific program. Drawing a conclusion about programs in general based on that evidence is unsound. Also, participation alone is not necessarily indicative of the interest in the programs; maybe people ARE interested, but just haven’t had new babies in their families.
The more standard flaw here, though, is the “real numbers versus percentages” issue. Evidence is presented about percentages, and based on that evidence, a conclusion is drawn about quantity. But the conclusion is flawed: what if there are 100 male executives at Company X, and 200 female executives? In that case, there would be 15 male executives taking Family Leave, and 20 female executives; since 20 is clearly more than 15, the conclusion would not be properly drawn in that case. We can see, then, that percentage evidence alone is not sufficient to support a conclusion regarding “real number” quantities.
Causation v. Correlation
The issue here is that there is a correlation between two occurrences (the increased lifespans of married men and the decreased lifespans of married women) and the argument inappropriately assumes that there must be a causal link between those occurrences. Whenever you see an argument that presents two events—let’s call them X and Y– that occur together, and that then concludes that one event, X, must be causing the other event, Y, you should look for the possibility that Y in fact causes X, or that some outside factor, Z, is causing both X and Y.
Necessary v. Sufficient
Now, I know we’ve seen a lot of necessary/sufficient issues in past discussions, but in flaw questions, the application is simpler. The correctly-identified flaw here would be that the argument takes a condition that is necessary for achieving the goal of completing the hike, and has treated it as though it is sufficient. Good boots are necessary; without them, Drew couldn’t make the hike. But are they ENOUGH? What if Drew has a horrible virus and can’t even get out of bed, let alone go for a 47-mile hike? The boots are not, by themselves, SUFFICIENT to ensure success on the hike. As a reader, be on the lookout for arguments that don’t differentiate between necessary and sufficient conditions.
GMAT Flaw Practice Question
* Reviewer: The book Art’s Decline argues that European painters today lack skills that were common among European painters of preceding centuries. In this the book must be right, since its analysis of 100 paintings, 50 old and 50 contemporary, demonstrates convincingly that none of the contemporary paintings are executed as skillfully as the older paintings.
Which of the following points to the most serious logical flaw in the reviewer’s argument?
(A) The paintings chosen by the book’s author for analysis could be those that most support the book’s thesis.
(B) There could be criteria other than the technical skill of the artist by which to evaluate a painting.
(C) The title of the book could cause readers to accept the book’s thesis even before they read the analysis of the paintings that supports it.
(D) The particular methods currently used by European painters could require less artistic skill than do methods used by painters in other parts of the world.
(E) A reader who was not familiar with the language of art criticism might not be convinced by the book’s analysis of the 100 paintings.
Step 1: Identify the Question
First, we read the question stem:
Which of the following points to the most serious logical flaw in the reviewer’s argument?
The key identifying language is typical in this example. The language most serious logical flaw indicates that we have a Flaw question. The question stem itself does not provide any information about what that conclusion is; we’ll have to find it in the argument. This is an Assumption Family question, so we may be able to brainstorm some assumptions while we read the argument. If so, that will help us with our task: to find an answer that points out a flaw in the reasoning of the argument.
Step 2: Deconstruct the Argument
First, the argument was written by the reviewer and I was asked to find a flaw in the reviewer’s argument. I need to keep that in mind.
The first sentence tells me the book’s conclusion: European painters today aren’t as good as European painters of the past. The reviewer then agrees with this premise because, according to the reviewer, a certain piece of evidence demonstrates (this) convincingly. The reviewer’s argument, then, is contained in the second sentence “ and that’s what I need to attack.
Your notes might look something like this (though there are lots of ways to write notes!):
R: AD says EP today worse than EP before
R: book is right bc 100 pntg anal shows this
[assumptions: the 100 paintings are fully representative of both eras; the author didn’t selectively choose 50 great old paintings and 50 mediocre contemporary paintings, etc.]
Note that I used abbreviations; you can use any you want as long as they make sense to you. Also note that I added some assumptions that I brainstormed; I may not actually write these down on the real thing, but I wrote them down for you.
Is the argument implying or assuming anything else? I’m brainstorming a scenario: the paintings that still survive from 200 or 300 years ago are only the absolute best paintings from those eras “ so it’s literally impossible to pick bad examples for the 50 old paintings set, because the bad paintings no longer exist. That would skew the argument, so the author is assuming that this has NOT happened.
Step 3: State the Goal
Our goal is to find an answer choice that points out a flaw in the reasoning of the argument. We can think of this flaw as a bad assumption: the author is assuming a certain thing to be true, but the author might be wrong. The wording of the correct answer, then, will tell us the opposite of the assumption. For example, if I say that Marielle must be a great basketball player because she’s six feet tall, I’m assuming that all you need to be a great basketball player is height. The flaw might be worded in this way: It’s not necessarily the case that someone will be a great basketball player simply because she’s tall. Alternatively, the flaw might be: someone can be tall and still not be a great basketball player.
The most common trap on this type of question is one involving an irrelevant distinction or comparison. For example, an incorrect answer choice might discuss alternate plans or paths when we were asked to comment on a particular plan given in the argument. Alternatively, an incorrect choice might discuss a detail or distinction that does not actually affect the conclusion.
Step 4: Work from Wrong to Right
(A) The paintings chosen by the book’s author for analysis could be those that most support the book’s thesis.
This is similar to one of the assumptions I brainstormed: the reviewer assumes that the chosen paintings are fully representative and that the book’s author didn’t have a skewed group of paintings for some reason. If the book’s author specifically chose paintings that most support a predetermined thesis, then that would be a major flaw in the reviewer’s argument that the evidence of the 100 paintings validates the book author’s thesis. This one looks pretty good so far but let’s check the other answers.
(B) There could be criteria other than the technical skill of the artist by which to evaluate a painting.
I agree, there are certainly other ways by which to evaluate a painting! This doesn’t address the particular argument at hand, though: finding a flaw in an argument that is specifically about the technical skill of European painters today and in the past. This is one of those irrelevant distinction or comparison answer choices: we don’t want to talk about other criteria because the argument itself focuses on technical skill. Eliminate B.
(C) The title of the book could cause readers to accept the book’s thesis even before they read the analysis of the paintings that supports it.
Once again, I agree that this is a potential danger. We were asked to find a flaw in the reseNavigator’s reasoning, however, and this answer discusses a flaw in the readers’ reasoning. Eliminate C.
(D) The particular methods currently used by European painters could require less artistic skill than do methods used by painters in other parts of the world.
This is yet another irrelevant distinction trap! The argument is very specific in comparing contemporary European painters with European painters of the past. Painters in other parts of the world are not a part of this argument. Eliminate D.
(E) A reader who was not familiar with the language of art criticism might not be convinced by the book’s analysis of the 100 paintings.
This sounds familiar “ it sounds a bit like answer C. This would be a problem with the reader’s reasoning, but we were asked to find a flaw in the reseNavigator’s reasoning, and the reseNavigator doesn’t address what the readers might think or do. Eliminate E.
The correct answer is A.
Key Takeaways for Solving Flaw CR Problems
- Know how to recognize this type. The question stem will typically use some variation of the word flaw, though it can occasionally contain alternate wording, such as vulnerable to criticism. Note: Weaken questions can also use the word flaw in the question stem. Weaken questions will also use some variation on the language if true. Flaw questions will not use if true language.
- Know what to do with Flaw questions. The argument will contain premises and a conclusion, and may also contain counter-premises. Such arguments always have assumptions, and we should note any that we might brainstorm. Our goal is to find an answer that points out that a particular assumption might not be true or valid.
- Watch out for traps! The answer choices often contain irrelevant distinction or comparison traps, trying to draw us away from the scope of the argument. We saw examples of this in all 4 wrong answers on the practice problem above. B and D tried to change the details on us so that we were no longer talking about the primary issues or situation discussed in the argument. C and E answered the wrong question: we don’t care what the readers think. We care about the reviewer’s reasoning.
* GMATPrep questions courtesy of the Graduate Management Admissions Council. Usage of this question does not imply endorsement by GMAC.
