Official Guide (OG) Study Notes: Critical Reasoning

The GMAT official guide defines three abilities measured by CR (Critical Reasoning):

Related：As you review your Critical Reasoning Official Guide study notes, ensure you delve into specific strategies for challenging formats, such as effectively tackling boldface questions.

Related：Because the GMAT is computer-adaptive, your CR performance feeds directly into the algorithm — understand how GMAT scoring works to shape your prep strategy.

• The ability to construct an argument
• The ability to evaluate an argument
• The ability to formulate or evaluate a plan of action

CR passages are usually less than 100 words and do not require any specialized knowledge or logical jargon, but you should at least be familiar with common logical terms such as premise, conclusion, and assumption.

What Does CR Measure? (What Is Measured)

An argument (reasoning) is a series of statements, where at least one statement supports another. Most CR passages contain arguments, while a few merely present objective information. Below are the various abilities measured by GMAT CR:

1. Analyzing Reasoning Structure

The ability to identify logical components such as premises, explanations, conclusions, and background information.

2. Drawing Conclusions (Inference)

The ability to derive conclusions from given information.

3. Identifying Sufficient or Necessary Assumptions (Identifying Assumptions)

The ability to identify assumptions that bridge logical gaps in explanations or plans.

4. Evaluating Hypotheses

The ability to identify hypotheses that explain a phenomenon.

5. Resolving Apparent Inconsistency

The ability to reconcile two seemingly contradictory pieces of information.

6. Strengthening or Weakening Reasoning

The ability to identify what additional information would strengthen or weaken the credibility of an argument.

7. Recognizing Logical Flaws

The ability to identify errors in reasoning (e.g., confusing causation with correlation, confusing sufficient and necessary conditions).

8. Identifying a Point of Disagreement

The ability to determine the key core issue in a dispute.

9. Finding a Solution

The ability to identify effective solutions to practical problems.

CR Test-Taking Strategies

1. Decide what works best for you: Read the question first or the passage first?

When reading the question, pay special attention to subtle semantic differences. For example, “valued by most citizens” and “most valued by the citizens” might lead to different answers.

2. Determine if the passage contains an argument or merely a statement of facts?

Consider whether the passage’s intent is to prove something, explain a phenomenon, or support a plan. You can use inference keywords (e.g., consequently, since) to help determine this, but be aware that some words have dual uses, and some passages may not provide keywords.

3. Identify the passage’s main proposition and argument structure

Identify the passage’s core proposition (conclusion, hypothetical explanation, or plan’s objective), and consider how the argument is derived. Note that the order of premises and conclusions is not fixed.

4. When examining an argument, try to find counterexamples

Try to think if there’s any situation where “all premises are true, but the conclusion is false.” Practice using the sentence structure: “Even if it’s true that…, who says… will definitely…?” to guide your thinking. Learning to judge the strength of each argument’s persuasiveness is very helpful for solving problems.

Logical Thinking Concepts Essential for the GMAT

1. Be alert to “implicit assumptions”

Any information that fills a logical gap in a passage is called an “implicit assumption.” It is divided into two types:

• Necessary Assumption: This assumption “must” be true for the argument to “possibly” hold.
• Sufficient Assumption: This assumption, “if true,” guarantees that the argument “will definitely” hold.

2. Understand the logical derivation of “If P, then Q”

“If P, then Q” can only logically imply “If not Q, then not P” (contrapositive). Common incorrect derivations include “If Q, then P” (converse) and “If not P, then not Q” (inverse).

3. Consider sufficient or necessary conditions

A necessary condition is one of the premises for an argument to hold; a sufficient condition alone guarantees that the argument holds.

4. Be careful with negative statements of and/or

• Not (A and B): A and B are not “both” true. (A might be true, B might be true, or neither might be true)
• Not (A or B): A is not true “and” B is not true.

5. Pay attention to General Statements

• Pay attention to the logical derivation between larger and smaller sets. For example, “All prime numbers are odd” is not equivalent to “All odd numbers are prime.”
• Some: Logically means “at least one,” and its negation is “none.”
• Every: Means “100% all,” and its negation is “not all.”
• Be aware of semantic differences. For example, “Everyone likes the same food” and “Everyone has food they like” are two different things.

6. Watch out for problematic definitions

Definitions that are too vague, too narrow, or circular will make an argument problematic. For example, the definition “An athlete is someone who runs fast or jumps high” is too narrow.

7. Consider how to confirm a hypothesis

To prove a hypothesis, you can conduct more similar experiments to ensure the results are not coincidental or exceptional, thereby strengthening the hypothesis’s credibility. At the same time, you should also consider whether the sampling is representative.