Critical Reasoning
Verbal
7 min readStrengthen questions ask you to choose the option that makes the argument more likely to be valid. The correct answer supports the link between the evidence and the conclusion. It does not prove the conclusion, and it does not need to be a necessary assumption. It only needs to increase the argument's credibility.
A strengthen answer can do several things:
The answer must connect to the argument's reasoning, not just its topic. A fact about the same subject can be irrelevant if it does not affect the conclusion.
Strengthening is about the link, not the conclusion. Ask what would make the evidence more supportive of the claim. The answer often removes a doubt or closes a gap.
An assumption is necessary. A strengthen answer is helpful. The correct strengthen choice may be stronger than an assumption, or it may be a different fact that makes the conclusion more plausible without being required.
For example, if the argument says a new study method improved test scores, an assumption is that the students used the method as intended. A strengthen answer could be that a second group using the old method scored lower. The second fact supports the conclusion but is not required for the argument to make sense.
Many arguments rely on a cause. The evidence shows that A happened before B, and the conclusion says A caused B. A strengthen answer can rule out another cause of B. If the argument says a new advertising campaign increased sales, a strengthen answer could show that the campaign ran in a region where no other marketing changed during the same period.
Example. Argument: A company introduced a new performance bonus and productivity rose the next quarter. Therefore, the bonus caused the increase.
Strengthen: During the same quarter, the company did not change its management, equipment, or production targets.
This rules out other explanations and makes the bonus a more likely cause.
When an argument generalizes from a sample, a strengthen answer can show that the sample is representative. If a survey of 100 customers finds that most prefer a new product, a strengthen answer could show that the 100 customers were randomly selected from the full customer base.
Conversely, a weaken answer would show that the sample was biased. The same fact can strengthen one argument and weaken another depending on the direction of the conclusion.
If the conclusion predicts a future result, a strengthen answer can show that the conditions for the prediction are present. For example, if a city predicts that a new transit line will reduce car traffic, a strengthen answer could show that the line connects residential areas with major employment centers and runs at convenient times.
The answer does not need to prove that the prediction will come true. It only needs to make it more likely.
Strengthen questions with numbers often require a baseline or a comparison. If a company says its profits rose after a new CEO took over, a strengthen answer could show that profits in the industry fell during the same period. The comparison makes the company's gain more impressive and more likely to be due to the CEO.
Be careful with percentages. A 20% increase from a small base may be less meaningful than a 5% increase from a large base. A strengthen answer can clarify the base or provide a relevant comparison.
A choice that restates the evidence does not add support. A choice that is consistent with the conclusion but does not affect its likelihood is irrelevant. A choice that supports a different conclusion is off track. A choice that is generally true but unrelated to the argument does not strengthen it.
Some choices strengthen a little, while others strengthen a lot. The GMAT usually asks for the choice that most strengthens. Compare the remaining choices and choose the one that closes the most important gap.
Causal arguments need more than a correlation. To strengthen a causal claim, show that the cause came before the effect, that the effect did not occur without the cause, or that other explanations are unlikely. A study that compares a group with and without the cause is stronger than a study that looks at only one group.
For example, an argument claims that a new study program improves scores. A strengthen answer could show that students were randomly assigned to the program and a control group, and that the two groups had similar scores before the program. Random assignment and a baseline comparison reduce the chance that another factor explains the difference.
Example. A city claims that installing brighter streetlights reduced crime. Which fact strengthens the claim?
A good strengthen: crime fell in the neighborhoods that received the new lights but did not fall in similar neighborhoods that kept the old lights. This comparison controls for broader trends and supports the causal link.
Recommendation arguments claim that a course of action will produce a benefit. A strengthen answer can show that the action is feasible, that the benefit is likely, or that the costs are lower than the alternatives. It can also show that the proposed action addresses the actual cause of the problem.
If a company recommends switching suppliers to reduce costs, a strengthen answer could show that the new supplier charges less for the same quality and can meet the company's delivery schedule. A choice saying the new supplier has a good reputation is weaker because it does not directly address cost or feasibility.
More than one choice may strengthen the argument. The GMAT asks for the choice that most strengthens. Prefer the choice that closes the central gap. A fact that supports a minor premise is less valuable than a fact that rules out the main alternative explanation.
A strengthen answer does not have to prove the conclusion. It only needs to make the conclusion more likely. The strongest choice usually affects the argument's main assumption, not a side detail.
| Argument pattern | Strengthen by |
|---|---|
| Cause and effect | Ruling out other causes |
| Sample to population | Showing the sample is representative |
| Prediction | Showing the conditions are present |
| Comparison | Providing a relevant baseline |
| Recommendation | Showing the benefits outweigh the costs |
The best strengthen answer usually feels like a missing piece of the argument. It does not repeat the conclusion and it does not introduce a new topic. It makes the evidence more relevant to the claim.
Free Critical Reasoning questions on this topic — try a few now.