ConceptVerbal

Assumptions: Find the bridge the argument needs

An assumption is an unstated claim the argument requires for its evidence to support its conclusion.

The correct answer does not need to prove the conclusion. It must protect a necessary bridge.

Separate evidence from conclusion

Consider:

A retailer plans to reduce product returns by adding more photographs to each product page.

Evidence may show that customers request more visual information. The conclusion is that more photographs will reduce returns.

The missing bridge could be:

Inadequate visual information contributes meaningfully to returns.

If returns mainly occur because deliveries are late, more photographs may have little effect.

Assumption versus strengthener

A strengthener makes the conclusion more credible. An assumption is something the argument cannot afford to lose.

Suppose a new fact says that customers enjoy high-resolution photos. That may sound favorable, but the plan does not necessarily require customers to enjoy them. It requires the photos to address a cause of returns.

The distinction is not “weak support versus strong support.” It is “helpful versus required.”

Use the negation test carefully

Negate a candidate assumption and ask whether the argument’s reasoning is seriously damaged.

Candidate:

A meaningful share of returns results from customers misunderstanding the product’s appearance.

Negation:

No meaningful share of returns results from customers misunderstanding the product’s appearance.

Under the negation, adding photos loses its proposed mechanism. That is strong evidence that the statement is necessary.

Negate the core claim, not every word mechanically.

Critical Reasoning Very Hard · assumption

A regional development agency argues that the government should approve a new paper mill on the river because it will create several hundred jobs and increase tax revenues. The mill will discharge warm water into the river, which would eliminate the trout population that supports a local sport-fishing industry.

Which of the following is an assumption required by the agency's argument?

A The economic benefits of the paper mill will exceed the economic losses to the sport-fishing industry.
B The sport-fishing industry currently provides no significant economic benefit to the region.
C The region cannot obtain comparable job and tax revenue gains through any industry other than paper milling.
D No alternative industry could generate more jobs and tax revenue for the region than the paper mill would.
E The agency has not deliberately misrepresented the mill's environmental impact in order to gain approval.

Answer: A

The agency concludes that the benefits justify the environmental costs. If the trout population is eliminated, the sport-fishing industry loses its basis, creating an economic loss. The argument must assume the paper mill's gains outweigh that loss, so A is required. B denies the existing benefit and is not supported. C and D impose uniqueness or optimality conditions not needed by the argument. E concerns intent, which is irrelevant to the cost-benefit logic.

Original GMAT-style question written for Premiergrad and checked by an independent blind solve. Not an official GMAT question.

What Lumen looks for

Lumen reads the answer you chose, not just whether it was wrong. On a question like this it separates three things that all look identical in a score: a concept you have not met, a reasoning step that went sideways, and a correct method pointed at the wrong target. Those need three different next weeks, and only the third one is fixed by re-reading the topic.

A single answer is weak evidence and Lumen says so. It becomes a diagnosis when the same shape shows up across several questions — which is the part a page like this cannot do for you.

Common wrong-answer patterns

a fact that strengthens but is not required
background information about the topic
a restatement of the conclusion
a claim outside the argument’s population or time period
a condition that would be sufficient to prove success but is not necessary

These map to Unstated Assumption, Scope Shift, and Necessary vs. Sufficient Confusion.

What mastery looks like

You can:

mark the evidence and conclusion separately
describe the gap before reading choices
distinguish required from merely helpful
negate a choice precisely
explain why the argument fails when the correct assumption is denied

Practice next with GMAT Assumption Questions or compare assumption logic with Evaluate the Argument.

Premiergrad can show not only why an option is wrong, but what kind of option it was—and why it looked attractive.

Practice assumption questions →

Trap Necessary vs. Sufficient
A necessary condition must be present for a result to occur. A sufficient condition guarantees the result. The GMAT…

Why a strengthener is not an assumption.
Concept Causal Reasoning
A causal argument says that changing or observing X explains a change in Y. The GMAT tests whether the evidence…

The argument family with the most predictable gap.
Practice GMAT Assumption Questions
An assumption is not just a fact that helps. It is a bridge the argument needs. This set makes that distinction visible…

Five arguments, with each wrong answer negated for you.

Knowing it and recognising it are different

Most people who miss questions on this concept can explain it perfectly. What separates them is spotting it when the question does not name it. The diagnostic tells you which of the two you are.

Practise this concept Everything on this page stays free and open — no account needed to read it or to attempt the questions above.

Last reviewed 2026-09-17