GMAT: Anatomy of a Weaken Question – Part 1

Weaken questions are among the most common CR question-type. When students get these questions incorrect, it’s usually for one of two reasons: either they did not understand the necessary assumptions, or they choose an answer choice that seemed logical rather than one that more clearly related to the argument. In this series, we’ll be dissecting Weaken Questions, looking closely at their wording, set-up, and answer choices. Hopefully after this series you’ll be on your way to better scores on this GMAT question-type!

Let’s start with the basics – how do you know you’re looking at a Weaken question? Here are some examples of the phrasing you might see on Test Day:

-Which of the following, if true, would most weaken the claim that periodontal disease is a cause of Coronary Artery disease?
-Which of the following, if true, casts the most doubt on the argument to the left?
-Which of the following, if true, most seriously weakens the argument to the left?

Sometimes the word “weaken” will be in the question itself, and sometimes not. The idea is that the answer choices will somehow hurt the passage’s claims.

What is being weakened? Most of the time the entire argument is being weakened, however occasionally only one aspect of the argument is being weakened, or a secondary conclusion. Make sure you know WHAT is being weakened. Otherwise, you risk choosing an answer choice that is weakening the wrong part of the argument!

-Which of the following, if true, most undermines the conclusion stated in the passage to the left?

In this question “the conclusion” is what needs to be weakened, so as you narrow down and compare answer choices, you will need to ask yourself: which choice hurts the conclusion the most? Two answer choices may sound logical, but only ONE will direct its venom more squarely on the conclusion.

In taking apart an argument, you should already be comfortable identifying the Conclusion, the Evidence, and coming up with 2-3 logical Assumptions. You will need to do this before you can answer any weaken question. Let’s refresh on an easy-level question:

Recent U.S. legislation limiting the emissions permissible from automobiles will require auto manufacturers to incorporate new technology and more costly components in cars. This will drive up the price of cars, both at home and abroad. Therefore, the legislation will result in the loss of many export markets.

Conclusion: Legislation = loss of export markets
Evidence: Legislation requires $$ technology; will drive up price of cars

We know that Evidence + Assumptions = Conclusion, so the assumptions here are anything that will increasingly link the legislation’s requirements to a loss of export markets. Ask yourself: why would the increasing price of cars lead to a loss of export markets? An “export market” means that the US cars are sold overseas. The idea here is that if they are more expensive, then no one overseas will buy them because they will be more expensive than their native automobiles.

Here’s how we could write that down in shorthand:

Assump: US cars are more expensive to foreigners; they will stop buying the US cars

Look out for Part 2 of this series to see how this Assumption relates to the answer choices in this question!