LSAT Parallel Reasoning

What It Is

Parallel Reasoning questions ask you to find an answer that uses the exact same pattern of reasoning as the stimulus. The subject matter is completely irrelevant -- only the logical structure matters.

How to Identify the Question Type

• Which of the following arguments is most similar in its reasoning to the argument above?
• The pattern of reasoning in which of the following is most parallel to the reasoning above?

Attack Strategy

• Step 1: Abstract the structure -- replace content with variables (All A are B; X is A; therefore X is B)
• Step 2: Note the conclusion type -- conditional, categorical, comparative?
• Step 3: Note whether the argument is VALID or FLAWED
• Step 4: Eliminate answers with a different number of premises, conclusion type, or validity
• Step 5: Match the abstract structure precisely to the remaining answers

Valid vs. Flawed Parallel

Critical rule: if the original argument is flawed (e.g., affirming the consequent), the correct parallel must also be flawed in the same way. If the original is valid, the parallel must also be valid. Never choose a valid answer to match a flawed stimulus or vice versa.

Example Problem

Stimulus (flawed): 'All champions train hard. Alex trains hard. Therefore, Alex is a champion.' Structure: All A are B; X is B; therefore X is A. (This is invalid -- affirming the consequent.) Parallel: 'All published authors write daily. Maria writes daily. Therefore, Maria is a published author.' Same invalid structure.

Top Tips

• Abstract the structure before looking at answers -- this alone eliminates most wrong answers quickly
• Subject matter similarity is a trap -- ignore it completely
• For Parallel Flaw specifically, identify the exact flaw type first