Critical Reasoning
Verbal
10 min readWelcome to the study of conclusions in Critical Reasoning. This guide will help you understand what an argument is, how to find its conclusion, and how to avoid common mistakes. We will start with the very basics and build up step by step.
On the GMAT Focus Edition, the Critical Reasoning section tests your ability to analyze arguments. An argument is a set of statements where some statements are used to support another statement. The statement being supported is the conclusion. The statements that do the supporting are called premises.
Questions about conclusions ask you to do one of two things:
The GMAT tests this skill because it is fundamental to clear thinking. In business, you must be able to separate what is known from what is being argued. You also need to know what can be safely inferred from data and what cannot.
Every argument has two main parts: premises and a conclusion. Sometimes there is also background information, which is not used as support but provides context.
Premises are facts, evidence, or assumptions that the author offers as reasons to believe the conclusion. They are statements that the author takes to be true for the sake of the argument. You do not need to judge whether premises are actually true; you just need to accept them for the purpose of the argument.
The conclusion is the main claim. It is the point that the premises are trying to prove. Every argument has exactly one main conclusion, though there may be intermediate conclusions that are supported by some premises and then used to support the main conclusion.
Think of an argument like a building. The premises are the foundation, and the conclusion is the roof. The roof rests on the foundation. If the foundation is weak, the roof collapses. In a well-structured argument, the conclusion must be supported by the premises.
For example:
All birds have feathers. A robin is a bird. Therefore, a robin has feathers.
Here, the premises are "All birds have feathers" and "A robin is a bird." The conclusion is "A robin has feathers."
In many arguments, there is a gap between the premises and the conclusion. The conclusion says something more than what the premises strictly imply. For example, from "Sales increased this quarter" you cannot conclude "Sales will increase next quarter." That conclusion goes beyond the evidence. Identifying this gap is crucial for drawing valid conclusions.
You will know you are dealing with a conclusion question by the wording of the question stem. Common phrases include:
Note that "must be true" questions are a type of conclusion question: you must choose an answer that is a logical consequence of the premises.
Here is a systematic method you can use for any conclusion question.
Ask yourself: What is the author trying to prove? Look for conclusion signal words such as therefore, thus, hence, so, consequently, as a result, it follows that, and this shows that. These words often introduce the conclusion.
Premise signal words include since, because, for, as, given that, and due to. These words often introduce support.
Place the word therefore before each candidate statement and see if it makes sense as a conclusion. For example, if you think "The sky is blue" might be the conclusion, try: "The sky is blue because it is a clear day." That works. Now try the other way: "It is a clear day because the sky is blue." That also could work, but which is the point? The author is more likely to be arguing that it is a clear day, using the blue sky as evidence.
Once you have the premises, ask: What must be true if these premises are true? The correct answer will be a statement that cannot be false if the premises are true. It will not add new information beyond what the premises support.
Remove any choice that goes beyond the evidence, is too broad, or is not supported. Also remove choices that are about something outside the scope of the argument.
For finding the conclusion, the correct answer is often a paraphrase of the main point. Wrong answers might be premises, background information, or a claim that is too strong or too weak.
For drawing a conclusion, the wrong answers often commit one of these errors:
This is the most common trap. The answer adds a new fact or makes a prediction that is not supported. For example, if the premises say "The company's profits increased last year," a wrong answer might say "The company's profits will increase again next year." That is a prediction, not a logical consequence.
The answer makes a general statement that covers more than the evidence. For example, if the premises talk about a specific product, a wrong answer might talk about all products.
If the premises say "All dogs are animals," a wrong answer might say "All animals are dogs." That is a reversal and does not follow.
Words like all, never, always, only, and must make a statement very strong. The premises usually support a weaker statement. For example, from "Most students passed" you cannot conclude "All students passed."
The answer brings in a fact or idea that is not mentioned in the premises. In a "must be true" question, the correct answer cannot introduce new information.
Argument: Since the new training program was introduced, employee productivity has increased by 15%. The increase in productivity is likely due to the training program. Therefore, the company should continue the program.
Question: Which of the following is the conclusion of the argument?
Solution: The author uses the productivity increase as evidence to support the recommendation that the company should continue the program. The phrase "therefore" introduces the conclusion. The conclusion is: "The company should continue the program." The other statements are premises.
Premises: All employees at XYZ Corp are required to complete a safety training course. Sarah is an employee at XYZ Corp.
Question: If the statements above are true, which of the following must also be true?
Solution: The correct answer is: "Sarah has completed the safety training course." This follows directly from the premises. Other answers might say "Sarah has completed other courses" or "All employees like the course," but those are not supported.
Premises: In a survey of 100 customers, 80 said they prefer brand A over brand B. The survey was conducted at a single store in New York.
Question: Which of the following is most strongly supported by the information above?
Correct answer: Some customers in the survey prefer brand A over brand B.
Why: This is a safe, direct consequence. It doesn't claim that all customers prefer A, or that the preference is nationwide, or that the survey is representative of all stores.
Wrong answers: "Most customers in the United States prefer brand A" goes beyond the evidence. "All customers surveyed prefer brand A" is too strong because 20 did not. "Brand A is better than brand B" is a value judgment not supported by the data.
Even at a beginner level, there are a few nuances to keep in mind.
Sometimes an argument has a sub-conclusion that is used to support the main conclusion. For example: "The company's profits are falling because costs have risen. Since profits are falling, the company may cut jobs." Here, "profits are falling" is a conclusion from the first premise, but it also serves as a premise for the final conclusion "the company may cut jobs." The main conclusion is the final claim.
When you have multiple premises, try to see which statement is the point. You can also ask: "Why does the author say this?" The answer will be the conclusion.
Pay attention to words like some, most, all, and none. A valid conclusion must respect the strength of the premises. If the premise says "some," you cannot conclude "most." If it says "most," you cannot conclude "all."
Mastering conclusions is the first step to doing well in Critical Reasoning. With practice, you will be able to identify conclusions quickly and avoid the common traps.
Free Critical Reasoning questions on this topic — try a few now.