Entailment questions on the LSAT (also called Inference questions or Must Be True questions) ask you to identify statements that must logically follow from the information provided in the stimulus. Unlike argument-based questions where you evaluate reasoning quality, entailment questions present a series of facts that you must accept as true, then ask what can be validly deduced or inferred from those facts. The two main types are: Must Be True questions where the correct answer must be 100% certain based on the stimulus facts with absolutely no room for doubt, and Most Strongly Supported questions where the correct answer is highly likely or best supported by the facts but allows minimal uncertainty. According to recent LSAT data, entailment/inference questions account for approximately 11-14% of Logical Reasoning questions, making them one of the top four most common question types alongside Strengthen, Weaken, and Flaw questions. The key skill tested is your ability to make valid logical deductions using only the information explicitly stated or necessarily implied in the stimulus—you cannot use outside knowledge, make assumptions beyond what's stated, or select answers that are merely possible but not required by the facts. Common deduction types include: combining conditional statements to form chains, applying contrapositives to if-then statements, working with quantifiers like "all," "some," and "most," understanding set relationships, and identifying necessary consequences of stated facts through Modus Ponens and Modus Tollens reasoning.

Must Be True and Most Strongly Supported are both entailment/inference question types, but they differ in the strength of certainty required. Must Be True questions require that the correct answer be 100% certain, rock-solid, with absolutely no room for doubt based on the stimulus facts. The answer MUST logically follow with complete necessity—there's no possibility it could be false if the stimulus is true. These use question stems like "must be true," "must also be true," "can be properly inferred," "logically follows," or "can be validly drawn." The standard is deductive certainty. Most Strongly Supported questions require that the correct answer be highly likely or best supported by the facts, but allow for minimal uncertainty or slight logical leaps. The answer should be the most probable conclusion, but doesn't need to be 100% guaranteed. These use stems with words like "most strongly supports," "most likely to be true," "most reasonable to conclude," or "best supported by." The standard is strong inductive support. The practical difference: Must Be True answers cannot introduce any information beyond what's in the stimulus and must be deductively certain—provable with mathematical precision. Most Strongly Supported answers might allow slightly related outside information that's commonly understood and can be inductively strong rather than deductively certain. However, both require the answer to be directly based on stimulus facts—the difference is degree of certainty (100% vs. 85-95%), not whether you're making things up. According to LSAC, both types test your ability to draw well-supported conclusions, which is one of the core skills in Logical Reasoning essential for legal analysis.

Solve LSAT entailment questions using this systematic approach: Step 1 - Read the question stem first to identify whether it's Must Be True (100% certain) or Most Strongly Supported (highly likely). Look for key words like "must," "necessarily," "logically follows" (Must Be True) or "most," "likely," "best supported" (Most Strongly Supported). Step 2 - Read the stimulus carefully, treating every statement as absolutely true fact. Unlike arguments where you evaluate reasoning, you're accepting facts and making deductions from them. Step 3 - Break down the stimulus into individual facts and identify any conditional statements (if-then relationships) or quantifiers (all, some, most, none). Number or mentally catalog each distinct piece of information. Step 4 - Look for ways to combine facts to reach new conclusions: overlapping terms in different statements suggest combinations, conditional chains where statements share terms, contrapositive inferences from if-then statements, and quantifier relationships. Step 5 - Pre-phrase possible inferences before reading answer choices—identify 1-3 valid deductions you can make from the facts. This prevents attractive wrong answers from misleading you. Step 6 - Evaluate each answer choice by asking: If the stimulus is true, must this answer be true (or is it most strongly supported)? Can I trace a clear logical path from stimulus to answer using only stated facts? Step 7 - Eliminate wrong answer types: introduces new information not in stimulus, only possibly true but not necessarily true, too strong when evidence is weaker, too weak when evidence is stronger, or contradicts the stimulus. Step 8 - Select the answer you can prove using only stimulus facts. For Must Be True, it must be deductively certain with no assumptions. For Most Strongly Supported, it should be the strongest inference even if not 100% guaranteed. The fundamental principle: make only valid deductions from stated facts without adding assumptions, outside knowledge, or information the stimulus doesn't support.

Entailment questions (Inference/Must Be True/Most Strongly Supported) are highly common on the LSAT, accounting for approximately 11-14% of all Logical Reasoning questions according to recent PrepTest analysis. With each Logical Reasoning section containing approximately 24-26 questions, you can expect about 3-4 entailment questions per LR section, or 6-8 entailment questions across the two Logical Reasoning sections on a complete LSAT. This makes entailment questions one of the top four most common question types, alongside Strengthen (~16%), Weaken (~15%), and Flaw (~14%) questions. According to PowerScore LSAT analysis of recent tests, Must Be True questions appeared 51 times across analyzed sections at 14.3% frequency, tied with Strengthen questions as highly prevalent. The frequency has remained relatively stable over recent years at 11-14%, though earlier LSAT administrations (pre-2015) sometimes featured entailment questions at even higher rates (~18-20%). Must Be True and Most Strongly Supported variants appear at roughly equal rates. Approximately 40% of entailment questions involve conditional logic requiring formal logical analysis, while 60% involve straightforward fact combination or quantifier reasoning. The importance of mastering entailment questions extends beyond their direct frequency because the underlying skill—making valid logical inferences from stated information—is fundamental to law school success, legal reasoning, and Reading Comprehension inference questions. According to LSAC's official description, "drawing well-supported conclusions" is explicitly listed as one of the ten core skills tested in Logical Reasoning, emphasizing that entailment reasoning is central to LSAT success and legal education.

Common entailment question stems fall into two categories based on certainty level. Must Be True stems (requiring 100% deductive certainty) include: "If the statements above are true, which one of the following must also be true?", "Which of the following can be properly inferred from the passage above?", "Which one of the following conclusions can be validly drawn from the passage?", "Which one of the following logically follows from the statements above?", "If the information above is correct, which of the following must be true?", "Which one can be correctly inferred from the information above?", "The statements above, if true, establish which of the following?", and "Which is necessarily true if the statements are accurate?" Most Strongly Supported stems (requiring high probability but allowing slight uncertainty) include: "The statements above, if true, most strongly support which one of the following?", "Which of the following is most supported by the information above?", "The information above provides the most support for which of the following?", "Which one of the following is most likely to be true based on the passage above?", "Which of the following conclusions is best supported by the statements above?", and "Which one is most reasonable to conclude based on the facts?" Key identification clues: The presence of "must," "necessarily," "validly," or "logically follows" indicates Must Be True requiring deductive certainty. The presence of "most," "likely," "best," or "reasonable" indicates Most Strongly Supported allowing strong inductive support. Important distinction: Don't confuse entailment stems with Strengthen question stems which reverse the direction—Strengthen asks "which of the following, if true, most strongly supports the argument" where new information in the answer supports the stimulus argument, whereas Inference asks "the stimulus supports which of the following" where the stimulus facts support the answer choice. The logical flow direction is opposite.

Common wrong answer traps on LSAT entailment questions include: 1) Could Be True But Not Must Be True - The answer is possible or consistent with the stimulus, but isn't required or proven by it. This is the single most common trap, accounting for ~40% of wrong answers. Example: Stimulus says "Some lawyers are wealthy," wrong answer says "Some lawyers are not wealthy" (could be true, but stimulus doesn't prove it). 2) Introduces Outside Information - The answer brings in concepts, terms, or ideas not mentioned in the stimulus. Even if the new info seems related or commonly known, it's wrong unless deducible from stimulus alone. 3) Reverses Conditional Logic - The answer incorrectly assumes the converse or inverse of a conditional statement. If stimulus says A→B, wrong answers claim B→A (converse) or ¬A→¬B (inverse), both invalid. 4) Too Strong for the Evidence - The answer uses absolute language ("always," "never," "must," "all") when the stimulus provides weaker support ("some," "many," "often," "most"). 5) Too Weak for the Evidence - The answer uses weak language ("might," "could," "possibly") when the stimulus provides strong definitive support allowing stronger claims. 6) Contradicts the Stimulus - The answer directly conflicts with facts stated in the stimulus (rare but easy to eliminate). 7) Attractive But Unsupported - The answer sounds reasonable, addresses interesting themes in the stimulus, or seems like common sense, but can't be logically proven from the facts. 8) Requires Unstated Assumptions - The answer is only true if you add assumptions beyond what the stimulus provides. 9) Confuses Correlation with Causation - The stimulus shows correlation (two things occur together), but the answer claims causation (one causes the other) not established. 10) Scope Shift - The answer talks about different people, times, places, or situations than the stimulus addresses. The key to avoiding these traps: Always ask "Can I prove this answer using ONLY the facts in the stimulus?" If you need to add anything beyond what's explicitly stated or necessarily implied, it's wrong.

Conditional logic is crucial for many LSAT entailment questions because it allows you to make valid deductions from if-then statements. Step 1 - Identify conditional statements in the stimulus. Look for: if...then, all, any, every, only, only if, unless, whenever, without. Step 2 - Translate into logical notation: "If A, then B" becomes \( A \rightarrow B \). This means A is sufficient for B (having A guarantees B) and B is necessary for A (can't have A without B). Step 3 - Understand valid inferences from \( A \rightarrow B \): Valid inference 1 is the contrapositive \( \neg B \rightarrow \neg A \) (if not B, then not A). The contrapositive is always true when the original is true and is logically equivalent. Valid inference 2 is Modus Ponens: if you know A is true, you can conclude B is true. Valid inference 3 is Modus Tollens: if you know B is false (¬B is true), you can conclude A is false (¬A is true). Invalid inferences you CANNOT make: Converse \( B \rightarrow A \) (affirming consequent—just because B occurred doesn't mean A caused it or that A is true), Inverse \( \neg A \rightarrow \neg B \) (denying antecedent—just because A didn't occur doesn't mean B won't occur). Step 4 - Form conditional chains: if the stimulus provides \( A \rightarrow B \) and \( B \rightarrow C \), you can validly deduce \( A \rightarrow C \) by chaining. Multi-step chains are common. Step 5 - Work with quantifiers: "All X are Y" means \( X \rightarrow Y \). "No X are Y" means \( X \rightarrow \neg Y \). "Some X are Y" doesn't create usable conditionals but tells you at least one X is Y. Step 6 - Apply to answer choices: correct answers often result from applying contrapositives, forming conditional chains, or using Modus Ponens/Tollens. Approximately 40% of entailment questions involve conditional logic, so mastering these valid inference forms is essential for LSAT success.

Entailment questions and Assumption questions are fundamentally different despite both involving logical reasoning. Entailment (Inference/Must Be True) questions present facts in the stimulus and ask what must follow from those facts—the logical flow is FROM stimulus TO answer choice. You're finding what the stimulus proves or supports. The stimulus is typically a series of facts without a conclusion you need to evaluate. You cannot add any information beyond what's stated—your answer must be provable using only stimulus facts. These ask: "If the stimulus is true, what else must be true?" The answer receives support FROM the stimulus. Assumption questions present an argument (premises + conclusion) and ask what unstated assumption the argument requires—the logical flow is what's NEEDED FOR the argument to work. You're finding what must be true for the argument's reasoning to be valid, but wasn't explicitly stated. The stimulus is an argument with a conclusion that depends on unstated assumptions. You're identifying gaps the author assumes away—bridges between premises and conclusion. These ask: "What must the author assume for this reasoning to work?" The answer provides support TO the argument's reasoning. Key differences: Direction - Entailment goes from stimulus to new conclusions. Assumptions go from conclusion back to what makes it valid. Stimulus type - Entailment typically has facts only. Assumptions have arguments with premises and conclusions. Information source - Entailment answers must come from stimulus. Assumption answers fill gaps in stimulus reasoning with unstated premises. Testing technique - Entailment: ask "does the stimulus prove this?" Assumption: ask "if this were false, would the argument fall apart?" (negation technique). Certainty - Entailment answers must be supported by stimulus. Assumption answers must be required by argument even though unstated. Both test logical reasoning skills essential for law school, but in opposite logical directions.

Pre-phrasing answers for LSAT entailment questions dramatically improves accuracy and speed by preventing attractive wrong answers from misleading you. Here's the systematic pre-phrasing process: Step 1 - After reading the stimulus carefully, pause before reading answer choices. Resist the temptation to jump to the answers immediately. Ask: What can I validly conclude from these facts? Step 2 - Look for obvious combinations: If the stimulus provides overlapping information in multiple sentences, identify how to combine them. If you see conditional statements, check for chains (A→B and B→C yields A→C) or contrapositive applications. If quantifiers appear (all, some, most, none), identify set relationships. Step 3 - Identify 1-3 specific inferences you can make. Don't try to predict exact wording, but identify the logical content. Example: Stimulus says "All managers are experienced. Sarah is a manager." Pre-phrase: "Sarah is experienced" (combining facts through Modus Ponens). Step 4 - Note the strength of your inference: Is it must be true (100% certain) or most strongly supported (highly likely)? This helps you match the question's certainty requirement and evaluate whether your pre-phrased inference fits the question type. Step 5 - Look for common inference patterns: Conditional chains, contrapositives, shared terms between sentences, quantifier relationships, or direct applications of stated conditionals to specific cases. Step 6 - When you read answer choices, immediately check if any matches your pre-phrased inference. If yes, verify it's correct by tracing the logical path, then select it. If no match appears, carefully evaluate each choice, but be suspicious of answers that seem appealing yet weren't inferrable when you analyzed the stimulus. Pre-phrasing prevents the common mistake of selecting answers that sound good or address interesting topics but aren't actually proven by the stimulus. It keeps you focused on what the facts actually establish rather than what seems plausible or reasonable based on outside knowledge.

Formal logic plays a significant role in LSAT entailment questions, particularly for questions involving conditional statements, quantifiers, and set relationships. The most important formal logic concepts: Conditional Logic - Understanding if-then relationships (\( A \rightarrow B \)), contrapositives (\( \neg B \rightarrow \neg A \)), and why converses and inverses are invalid. Approximately 40% of entailment questions involve conditional logic according to recent LSAT analysis. Symbolic Notation - Translating "if A then B" into \( A \rightarrow B \) makes relationships visual and easier to manipulate. Using \( \neg \) for "not" clarifies negations. This is especially helpful for complex multi-conditional stimuli. Contrapositive Formation - Automatically converting \( A \rightarrow B \) into \( \neg B \rightarrow \neg A \) is essential for many entailment questions. The contrapositive is logically equivalent to the original statement and always valid. Conditional Chains - Recognizing that \( A \rightarrow B \) and \( B \rightarrow C \) yields \( A \rightarrow C \). Multi-step chains appear frequently in entailment questions. Quantifier Logic - Understanding "all," "some," "none," "most" and their formal relationships. "All X are Y" means \( X \rightarrow Y \). "No X are Y" means \( X \rightarrow \neg Y \). "Some X are Y" means at least one X is Y but doesn't create usable conditionals. "Most" means more than 50% (majority). Venn Diagrams - Visualizing set relationships helps with quantifier questions involving overlapping categories. Modus Ponens and Modus Tollens - Valid inference forms: if \( A \rightarrow B \) and A is true, then B is true (Modus Ponens). If \( A \rightarrow B \) and B is false, then A is false (Modus Tollens). However, formal logic expertise isn't required for all entailment questions—many test straightforward fact combination without symbolic logic. Approximately 60% of entailment questions can be solved through careful reading and intuitive fact combination. The key is recognizing WHEN formal logic applies (conditional language, quantifiers, complex chains) versus when simple reading comprehension and fact combination suffice. Practice both symbolic translation for complex conditionals and intuitive reasoning for straightforward fact-based questions. According to LSAC, the ability to work with formal logical relationships is a core skill tested throughout Logical Reasoning.