Introduction to Logical Reasoning

Logical reasoning questions make up approximately half of scored portion of the LSAT. Each logical reasoning question requires you to either analyze a short argument or to us a fact pattern to reason in a particular way. For example, you might be asked to identify the conclusion of an argument, to describe how an argument reasons to its conclusion, or to make a logical inference from a given set of facts.

All logical reasoning questions consist of the following three elements:

  • Stimulus
  • Question Stem
  • Answer Choices

Consider the following question from Section 2 of the June 2007 LSAT (full test available here):

The stimulus is listed first. In this case, the stimulus contains an argument. The question stem is listed second. In this case, the stimulus asks us to identify the conclusion of the argument. Last, five answer choices are listed. Four of the answer choices are incorrect, and one is correct.

Even though the stimulus is listed before the question stem, you should always read the question stem first. The question stem contains your what your task is for the question. Thus, the question stem determines what you ought to be thinking about or looking for as you read the stimulus. Your strategy  questions that ask you to simply identify the conclusion questions will likely be different than your strategy for questions that ask you to determine how the argument is flawed.

The different tasks contained in various question stems allow us to categorize logical reasoning questions into different question types.  Categorizing by question type allows us to come up with specific strategies for the different kinds of tasks demanded of us in the logical reasoning sections. The following question types make up the overwhelming majority of logical reasoning questions:

  • Identify the Conclusion
  • Complete the Argument
  • Role of a Statement
  • Method of Reasoning
  • Point of Agreement/Disagreement
  • Evaluation the Argument
  • Necessary Assumption
  • Sufficient Assumption
  • Most Strongly Supported
  • Must Be True
  • CANNOT be True
  • Weaken
  • Strengthen
  • Flaw
  • Parallel Flaw
  • Extract the Principle
  • Parallel Principle
  • Principle Justify
  • Explain the Paradox
  • Parallel Reasoning

We will look at each question type, covering both how to identify questions within the various types and the best strategies for dealing with each question type.