GMAT Critical Reasoning: Inference Vs. Assumption Examples

GMAT - Inference vs Assumption

The reason GMAT aspirants get confused between Inference and Assumption is the phrase, ‘Must be true’ that resonates in both places. Moreover, neither inference nor assumption is explicitly stated in the argument. But, they hold good if the argument is true.

Inference is something that can be validated to be true, from the information presented in the argument. It is a logical deduction from a part or whole of the argument. It is never explicitly stated in the argument. But it is just as true as anything that is written in the passage. If you make a mental map out of premises and conclusion of the argument, the inference follows the conclusion.  The question stem here is, ‘if the statements above are true, which of the following must be true?’
Generally, in GMAT Exam, an inference question does not have an explicit conclusion in the argument or in the question stem. It’s left to be inferred.

Assumption is a hidden or unstated premise. It must be true if the conclusion is true. And it is not something that can be logically derived from the other information given in the argument. In the mental map you make of premise, conclusion, inference, an assumption holds its place between premise and conclusion. The question stem here is which of the following is an assumption on which the argument depends? Assumption questions generally have a defined conclusion using which you can deduce assumptions.


Recently, in the state of ABC, the use of seat belts in cars and other passenger vehicles has been made mandatory. While there is not much difference in the number of accidents, the number of life threatening injuries caused by accidents has gone down with the new rule.

What can possibly be the assumptions and inferences in this argument?


People are wearing their seat belts after the rule has been implemented in the state of ABC. The premise is that the rule has been made mandatory. It is not stated that people are following the rule. This is an assumption that leads the premise to the conclusion about reduced number of injuries.

One can also safely assume that using seat belts does not reduce the number of accidents.


There can be multiple inferences here. One such inference is that the new rule and its implementation are very effective in reducing the number of life threatening injuries from car and vehicular accidents in the state of ABC.

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