LSAT Logical Reasoning Question Stems List
Every Logical Reasoning question belongs to a type, and the question stem tells you which one before you read a single word of the argument. Read the stem first, name the type, and you know what the right answer has to do: prove, help, hurt, or describe the argument. The table below lists the stems for every major type, with the trigger words that identify each one.
What are the LSAT Logical Reasoning question stems?
A question stem is the sentence after the stimulus that tells you what to do with it: "Which one of the following, if true, most strengthens the argument?" or "Which one of the following must be true?" Each stem maps to one question type, and each type has its own standard for a right answer. The fastest improvement most beginners can make in Logical Reasoning is not learning more logic. It is reading the stem first and naming the type before reading the stimulus, because the type decides what counts as evidence, what counts as a trap, and how hard you should push on each answer choice.
There are about 15 types that appear regularly, and they fall into four families. Learn the families first, then the individual stems. If you can place a stem in its family in a few seconds, you already know the shape of the right answer.
The four families
| Family | What the answer does | Types in it |
|---|---|---|
| Prove | Follows from the stimulus, or describes it | Must be true, main point, point at issue, method of reasoning, must be false |
| Help | Makes the argument stronger or complete | Necessary assumption, sufficient assumption, strengthen, resolve the paradox, principle (justify) |
| Hurt | Damages the argument or exposes its flaw | Weaken, flaw, parallel flaw, evaluate the argument |
| Match | Mirrors the argument in another case | Parallel reasoning, principle (conform) |
The family rule is a shortcut, not a substitute for the type. Strengthen and necessary assumption are both in the help family, but a strengthen answer only needs to help, while a necessary assumption answer must be required: if it is false, the argument falls apart. That distinction is where most help-family misses happen. Our necessary vs. sufficient assumptions guide walks through it with examples.
The full stem list, by type
Stem wording varies from test to test, but the trigger words stay the same. Learn the trigger, not the exact sentence.
| Question type | Typical stems | Trigger words |
|---|---|---|
| Must be true / most strongly supported | "If the statements above are true, which one of the following must also be true?" / "Which one of the following can be properly inferred?" | must be true, properly inferred, most strongly supported |
| Main point | "The main point of the argument is that..." / "Which one of the following most accurately expresses the main conclusion?" | main point, main conclusion |
| Point at issue / point of agreement | "A and B disagree about whether..." / "The statements above provide the most support for the claim that A and B agree that..." | disagree, agree, point at issue |
| Necessary assumption | "Which one of the following is an assumption required by the argument?" / "The argument relies on the assumption that..." | assumption required, relies on, depends on |
| Sufficient assumption (justify the conclusion) | "Which one of the following, if assumed, allows the conclusion to be properly drawn?" / "The conclusion follows logically if which one of the following is assumed?" | if assumed, properly drawn, follows logically |
| Strengthen | "Which one of the following, if true, most strengthens the argument?" / "Which one of the following most supports the argument?" | most strengthens, most supports |
| Weaken | "Which one of the following, if true, most seriously weakens the argument?" / "Which one of the following most undermines the argument?" | most weakens, undermines, calls into question |
| Flaw in the reasoning | "The reasoning is flawed in that the argument..." / "The reasoning is most vulnerable to criticism on the grounds that the argument..." | flawed, vulnerable to criticism, error in reasoning |
| Method of reasoning | "The argument proceeds by..." / "Which one of the following describes the technique of reasoning used above?" | proceeds by, technique, method |
| Parallel reasoning | "The reasoning in which one of the following is most similar to that in the argument above?" | most similar, parallel, reasoning |
| Parallel flaw | "Which one of the following exhibits flawed reasoning most similar to that in the argument above?" | flawed reasoning most similar |
| Evaluate the argument | "Which one of the following would be most useful to know in evaluating the argument?" | useful to know, evaluating |
| Resolve the paradox | "Which one of the following, if true, most helps to resolve the apparent discrepancy?" / "Which one of the following most helps to explain the apparent paradox?" | resolve, explain, discrepancy, paradox |
| Principle | "Which one of the following principles, if valid, most helps to justify the reasoning?" / "Which one of the following principles most closely conforms to the reasoning above?" | principle, justify, conforms |
| Must be false | "If the statements above are true, which one of the following must be false?" / "Which one of the following cannot be true?" | must be false, cannot be true |
Guides for the most common types are already in this library: flaw, inference (must be true), main point, point at issue, strengthen and weaken, method of reasoning, parallel reasoning, principle, evaluate the argument, and must be false. The full type-by-type map is in our Logical Reasoning question types guide.
Tricky stems that hide the type
Five stem forms regularly fool students who know the standard list but not the variants:
- "Most vulnerable to criticism" means flaw, not weaken. A weaken stem asks for a new fact that hurts the argument. A flaw stem asks you to describe what is already wrong with it. Same family, different job. Our flaw guide covers the distinction.
- "Except" flips the task. "Each of the following could be true EXCEPT" is a must be false question: four choices are possible and one is impossible. "Each of the following strengthens the argument EXCEPT" asks for the one choice that does not help. Always read past the word "except" before deciding what to look for.
- Fill-in-the-blank stems are ambiguous until you read the stimulus. "Which one of the following most logically completes the argument?" can be a must-be-true question (the blank is supported by the facts) or a strengthen question (the blank helps the conclusion). Read the stimulus, then decide which job the blank is doing.
- Principle splits into two types. A principle that "justifies" or "helps to justify" the reasoning is a help-family question: find the rule that makes the argument work. A principle that "conforms to" the reasoning is a match-family question: find the rule the argument already follows. The verb in the stem decides.
- "Assumption" alone is not enough. "An assumption required by the argument" is necessary assumption. "If assumed, allows the conclusion to be properly drawn" is sufficient assumption. One word, "required" versus "allows," changes the standard completely. Confusing them is the single most common assumption miss, and it is covered in our necessary vs. sufficient guide.
How to practice stem recognition
Stem recognition is a drill, not a reading exercise. It takes about 15 minutes and it pays off on every section:
- Cover the stimulus. Take a set of Logical Reasoning questions and read only the stems. Name the type and family for each one, out loud, before uncovering anything else.
- Sort your misses by stem, not by topic. If you keep missing strengthen questions, the problem is usually the standard (helping is enough), not the subject matter. A miss log grouped by type shows this in a week. Our mistake-tracking guide shows how to set one up.
- Drill the five tricky forms separately. Except stems, fill-in-the-blank stems, principle splits, "vulnerable to criticism," and the two assumption stems account for a disproportionate share of misclassified questions. Ten of each, stem only, is enough to make them automatic.
- Then stop drilling stems. Once classification takes a few seconds, the bottleneck moves back to reading arguments. Spend the saved time on the types you miss most, usually flaw, strengthen, and assumption questions, which appear far more often than the rare types.
As of October 2026, the current LSAT has two scored Logical Reasoning sections, and every section mixes these types. Reading the stem first does not just save time. It stops the most expensive error in the section: answering the right question type with the wrong standard.
Frequently asked questions
What is an LSAT Logical Reasoning question stem?
The stem is the question sentence that follows the stimulus. It tells you what to do with the argument: prove something from it, help it, hurt it, describe it, or match it. The stem decides the question type, and the type decides what counts as a right answer.
Should you read the stem before the stimulus?
Yes. Reading the stem first tells you what to look for while you read the argument. A flaw stem sends you hunting for the gap; a strengthen stem sends you looking for the missing support. Reading the stimulus blind and then discovering the type wastes the first read.
How many Logical Reasoning question types are there?
About 15 types appear regularly: must be true, main point, point at issue, necessary assumption, sufficient assumption, strengthen, weaken, flaw, method of reasoning, parallel reasoning, parallel flaw, evaluate the argument, resolve the paradox, principle, and must be false. They fall into four families: prove, help, hurt, and match.
What does 'most vulnerable to criticism' mean?
It is a flaw question. It asks you to describe what is already wrong with the reasoning, not to add a new fact that hurts it. That second job belongs to weaken questions, and confusing the two is a common miss.
What does an 'except' stem ask for?
It flips the task. 'Each of the following could be true EXCEPT' is a must be false question: four choices are possible and one is impossible. 'Each of the following strengthens EXCEPT' asks for the one choice that does not help. Always check for 'except' before choosing.