Logical reasoning strategies and techniques - Understanding ...

Learning Outcomes

By the end of this article, you will be able to identify LSAT Logical Reasoning question stems, distinguish between main question types, and determine exactly what each question requires you to do. You will learn how to extract task instructions from question wording and apply targeted strategies accordingly. This will help you approach each Logical Reasoning question efficiently and avoid common mistakes associated with misreading the task.

LSAT Syllabus

For LSAT, you are required to understand the purpose of each Logical Reasoning question stem and use its language to determine the correct strategy for each item. Pay attention during revision to:

• recognising and interpreting the question stem to identify the required task
• distinguishing between different LSAT question types (e.g. Main Point, Assumption, Flaw, Strengthen, Weaken, Inference, Principle, Parallel Reasoning)
• applying targeted approaches for each task based solely on the question stem’s language

Test Your Knowledge

Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, remember to look more closely at that area during your revision.

1. What does the phrase "which one of the following, if true" usually indicate about the information provided in the answer choices?
2. How can you tell whether a question wants you to find a conclusion, an assumption, or something else?
3. In a 'must be true' question, what is the required relationship between the answer and the stimulus?
4. Why is it important not to use outside information when approaching LSAT Logical Reasoning tasks?

Introduction

Every Logical Reasoning question on the LSAT starts with a question stem—this short prompt tells you exactly what to do with the argument or passage that precedes it. Precise task identification based on the stem's language is essential for selecting the correct strategy and avoiding errors.

Misinterpreting the stem can cause you to answer the wrong question, waste time, or pick attractive but incorrect options. You must train yourself to extract the required approach from just a few critical words in each stem.

Why the Question Stem Matters

The LSAT does not always state tasks in a straightforward way. Instead, it uses distinctive phrasing to signal the skill being tested: identifying conclusions, detecting assumptions, describing flaws, applying principles, drawing inferences, or evaluating new information. Before reading the argument carefully, always read the question stem.

Key Term: question stem
The sentence or phrase following the argument that specifies exactly what the test-taker must do to answer the question.

Decoding Typical LSAT Stem Language

Each question type uses particular cues. Attending to these will reveal the task:

• "Which one of the following most accurately expresses the main conclusion..." (Main Point)
• "Which one of the following is an assumption required by the argument?" (Necessary Assumption)
• "Which one of the following, if true, most seriously weakens the argument?" (Weaken)
• "Which one of the following, if true, most strongly supports the argument?" (Strengthen)
• "If the statements above are true, which one of the following must also be true?" (Inference)
• "The reasoning in the argument is most vulnerable to criticism on the grounds that..." (Flaw)
• "Which one of the following conforms most closely to the principle stated above?" (Principle)
• "Which one of the following exhibits a pattern of reasoning most similar to..." (Parallel Reasoning)

Key Term: task identification
The process of determining what the question stem is instructing you to do with the information provided.

Actionable Process: Reading Before the Argument

Read the question stem before the argument. Doing so allows you to focus on only what is needed. For a "weaken" question, for example, you will read the argument with an eye to finding its key assumption or vulnerability. For a "main point" question, you’ll seek the author’s central claim.

Worked Example 1.1

Question Stem: "Which one of the following most accurately expresses the main conclusion of the argument?"

• Task: Identify the author's main point (the conclusion), not an unstated assumption or a supporting premise.
• Approach: Read the argument looking for conclusion indicators ("thus", "therefore"), then paraphrase the main claim before checking answer choices.

Answer:
The stem signals a "Main Point" task; you must find the key assertion that all other statements in the argument support.

Worked Example 1.2

Question Stem: "Which one of the following, if true, most seriously undermines the argument?"

• Task: Find the answer choice that most weakens the conclusion, usually by challenging a key assumption or suggesting an alternative explanation.
• Approach: Read for the argument's gap, then seek an answer that exploits it.

Answer:
This stem means you are facing a "Weaken" question; your job is to find new information that reduces the argument's persuasiveness.

Worked Example 1.3

Question Stem: "If the statements above are true, which one of the following can be properly inferred?"

• Task: Select an answer that logically follows from the argument.
• Approach: Accept the premises as 100% true. Do not use outside knowledge or make unwarranted extrapolations.

Answer:
This is an "Inference" or "Must Be True" question; the correct answer must be directly supported by the passage's statements.

Exam Warning

Failing to correctly identify the task can lead to applying the wrong method and falling for tempting distractor answers. Never assume the question-type based only on familiar words—always check the instruction carefully.

Overview Table: Common Stem Cues and Required Tasks

Strategy: Adapting to Stem Variations

Pay attention to subtle shifts in stem wording. For instance:

• A "Which one of the following allows the conclusion to be properly drawn?" stem requires picking an answer that, if assumed true, guarantees the conclusion (Sufficient Assumption).
• A "Which one of the following...is a principle that justifies the reasoning?" stem directs you to find a broad rule matching the logic (Principle).
• A "Which...pattern of reasoning is most similar to..." stem wants you to map out the argument’s structure and match it to an answer.

Revision Tip

When you encounter less familiar stems (e.g., "Which one of the following, if true, most helps to resolve..."), break down the stem into its action ("helps to resolve" = explain a paradox), then match your reading strategy appropriately.

Summary

Identifying the question stem’s task is the first key step for every Logical Reasoning question. The stem’s wording functions as an "instruction manual"—follow it to choose the correct approach. This prevents misreading, wasted effort, and avoidable mistakes.

Key Point Checklist

This article has covered the following key knowledge points:

• How to extract the precise instruction from the question stem before analysing the argument
• Typical language cues for major LSAT Logical Reasoning question types and their required tasks
• The importance of matching your approach to the stem’s demand, not to the argument itself
• Why reading the stem first improves accuracy and efficiency on the LSAT

Key Terms and Concepts

• question stem
• task identification