LSAT Logical Reasoning Question Types
Every LSAT logical reasoning question type, explained as a usable cheat sheet — how to recognise each one, the move to make, and a mini-example. Identify the type first and the section gets far easier.
On the LSAT, identifying the question type before you read the argument is half the battle — the stem tells you exactly what to look for. Below is a usable cheat sheet: every common Logical Reasoning question type, grouped by family, with how to recognise it and the move to make. Then practise them on our LSAT practice questions.
Assumption-based questions
The argument has a gap between its support and its conclusion; these questions are about that gap.
| Type | How to spot it | The move |
|---|---|---|
| Necessary assumption | Stem: "the argument assumes / depends on / requires…" | Find the premise the argument needs to work; negate a choice — if the argument falls apart, it is the answer. |
| Sufficient assumption | Stem: "which, if assumed, allows the conclusion to be drawn?" | Find a premise that, added in, makes the conclusion airtight — even if it is stronger than strictly needed. |
| Strengthen | Stem: "which, if true, most strengthens…" | Add a new fact that confirms the assumption or rules out an objection. |
| Weaken | Stem: "which, if true, most weakens / undermines…" | Attack the assumption — usually by offering an alternative explanation. |
| Flaw | Stem: "the reasoning is flawed because / is vulnerable to criticism…" | Name the error: correlation-causation, unrepresentative sample, circular reasoning, etc. |
Inference-based questions
Stick to exactly what the statements support — no outside assumptions.
| Type | How to spot it | The move |
|---|---|---|
| Must be true (inference) | Stem: "which must be true / is most strongly supported?" | Pick the choice the premises guarantee; eliminate anything that needs an extra assumption. |
| Cannot be true | Stem: "which cannot be true / is most strongly contradicted?" | Find the choice that conflicts with the stated facts. |
Structure-based questions
These ask about how the argument is built rather than whether it is right.
| Type | How to spot it | The move |
|---|---|---|
| Main point | Stem: "main conclusion / main point of the argument is…" | Identify the claim the rest of the argument supports — not a premise. |
| Method of reasoning | Stem: "the argument proceeds by…" | Describe the technique (e.g. analogy, counterexample, ruling out alternatives). |
| Parallel reasoning | Stem: "most similar in its reasoning to…" | Match the logical structure, not the topic. |
| Principle | Stem: "which principle…justifies / conforms to…" | Bridge a general rule to the specific case in the stimulus. |
How to use the cheat sheet
Read the question stem first, name the type, and recall the move before you tackle the argument. The assumption family (assumption, strengthen, weaken, flaw) is the most common, so master it first. Then drill with the practice questions, and warm up your core reasoning with the logical reasoning test.
Frequently asked questions
How many LSAT logical reasoning question types are there?
Most prep systems group them into about 10–12 types, but they cluster into a few families: assumption-based (assumption, strengthen, weaken, flaw), inference-based (must be true, most strongly supported), and structure-based (main point, method, parallel reasoning).
Which LSAT logical reasoning question types are most common?
Assumption, strengthen/weaken, flaw and inference questions make up the bulk of the section, so they are the highest-leverage types to master first.
How do I identify the question type?
Read the question stem before the stimulus. The stem ("which of the following, if true, most weakens…", "the argument assumes…", "must be true…") tells you the type, which tells you exactly what to look for in the argument.