Prepare for the LSAT

What to practice: Necessary assumptions, sufficient assumptions, missing links and the negation test.

1. Separate the conclusion from the evidence offered for it. Name the gap without adding facts to the argument.
2. For a necessary assumption, look for something the reasoning cannot do without. Negate the candidate precisely and ask whether the support collapses; a necessary assumption need not prove the conclusion.
3. For a sufficient assumption, add the choice to the premises and check whether the conclusion must follow. A helpful or plausible statement is not enough.
4. Keep quantifiers and conditions intact. The negation of “all” is “not all,” rather than “none”; the negation of “some” is “none.”

Check your work: Before testing choices, say whether the question asks what is required or what is enough.

What to practice: Causal arguments, comparisons, studies, plans, alternative explanations and relevant new evidence.

1. Identify the exact conclusion, including the population, time period and strength of the claim.
2. Accept the stated premises and locate the uncertain link. For causal claims, consider selection effects, reverse causation or another change that could explain the result.
3. Treat each answer as true and ask what happens to that link. Strengthening need not prove the conclusion; weakening need not prove its opposite.
4. Compare how directly the remaining choices address the reasoning. Background information about the topic can be accurate without changing the argument.

Check your work: Finish the sentence: “This changes support for the conclusion because…”

What to practice: Conditional reversals, causal errors, unrepresentative samples, shifting meanings, false alternatives and part–whole errors.

1. Write a short version of the argument using only its premises and conclusion. Notice any change in meaning, population or level of certainty.
2. Look for a possible situation where the premises hold but the conclusion fails. That counterexample reveals what the reasoning overlooked.
3. For conditional rules, distinguish “if,” “only if” and “unless.” A rule that all A are B does not establish that all B are A.
4. Choose the description that accurately states both the evidence used and the mistake made. A familiar flaw label is not enough if its details do not fit.

Check your work: Give a counterexample that preserves every premise and defeats the conclusion.

What to practice: Must-be-true and most-supported claims, conditional chains, quantifiers and constrained conclusions.

1. Match the standard in the question. A must-be-true choice must hold in every situation allowed by the statements. A most-supported choice needs the strongest evidence among the options, without necessarily being guaranteed.
2. Translate conditional relationships carefully and use valid contrapositives: if A implies B, not-B implies not-A. Reversing the arrow is not equivalent.
3. Track quantifiers. “Some” means at least one; “most” does not mean all. Two overlapping descriptions do not establish an overlap unless the premises force it.
4. For must-be-true questions, a counterexample that preserves all the statements rules a choice out. For most-supported questions, compare the strength of the textual evidence; a merely possible exception does not by itself rule a choice out.

Check your work: For must-be-true, look for a counterexample. For most-supported, explain why the evidence favors this choice over the alternatives.

What to practice: Main conclusions, intermediate conclusions, premise roles, reasoning methods and points of disagreement.

1. Ask which claim the other statements are intended to establish. The main conclusion need not be the last sentence.
2. Draw the support relationships. An intermediate conclusion receives support and then supports a further conclusion.
3. Distinguish the author’s view from an opponent’s view, a concession or background information. A sentence mentioned by the author is not necessarily endorsed.
4. For disagreement questions, require evidence that one speaker accepts the statement and the other rejects it. Silence about an issue is not disagreement.

Check your work: Use “because” and “therefore” to show the direction of support between claims.

What to practice: Principle application and justification, parallel arguments and parallel flaws.

1. For a principle, identify its triggering conditions and what it permits, requires or forbids. Check that the case satisfies every condition.
2. For a justification question, choose a rule strong enough to bridge the premises to the stated judgment.
3. For parallel reasoning, replace topic-specific nouns with simple labels. Preserve the number of groups, conditional direction, quantifiers and conclusion strength.
4. If asked for a parallel flaw, match the same invalid move. An argument about the same topic can be structurally different.

Check your work: Compare the abstract structure before the real-world topic.

What to practice: Paradoxes, unexpected comparisons, changes in totals and rates, and reconciling reported results.

1. State the two observations separately. Identify why they appear surprising together.
2. Keep both observations fixed. A choice that simply denies one of them does not explain the discrepancy.
3. Look for a difference in groups, time periods, denominators, incentives or measurement that connects the facts.
4. Check whether the choice would actually make the result less surprising. A general fact that could accompany either outcome has little explanatory value.

Check your work: Explain how the new fact connects both sides of the apparent contradiction.

What to practice: Main ideas, primary purpose, author attitudes and passage summaries.

1. Give each paragraph a brief job description: introduces a problem, explains a view, challenges it or proposes a qualification.
2. Track the author’s own position separately from views the passage reports. Pay attention to transitions that reveal agreement or criticism.
3. Before reading the choices, write a one-sentence statement covering the passage’s central development and conclusion.
4. Reject answers that cover only one example, omit the main qualification or turn a cautious claim into an absolute one.

Check your work: Check that the answer covers the passage’s central argument, including its qualification.

What to practice: Supported inferences, author agreement, stated details, words in context and applying a passage’s claims.

1. Return to the relevant lines and read their context. Keep track of the person or theory to which a claim belongs.
2. Combine the passage’s statements only as far as they support. Do not add outside knowledge or assume the author endorses a view merely described.
3. Compare the answer’s certainty with the text’s certainty. Possibility, likelihood and necessity are different claims.
4. For a new example, identify the passage’s operative distinction and apply that distinction consistently to the new facts.

Check your work: Point to the evidence for each meaningful word in the answer, especially words such as all, only and never.

What to practice: Paragraph roles, organization, examples, analogies, concessions and shifts in perspective.

1. Map the sequence of ideas using functions rather than summaries of the subject matter.
2. For a quoted sentence or example, examine the claim immediately before it and the conclusion drawn after it.
3. Distinguish evidence for the author’s position from an objection the author will answer or a view offered only for context.
4. Check the whole answer. A choice can describe the example accurately yet misstate which claim it supports.

Check your work: Complete “The author includes this to…” with a function, not another summary of the example.

What to practice: Paired passages, agreement and disagreement, relationships, shared assumptions and cross-passage applications.

1. Read each passage as its own argument. Record its main position, evidence, qualifications and tone.
2. Compare the passages on the precise question asked. They can agree about a policy while disagreeing about its justification or scope.
3. For an answer claiming agreement, find support in both passages. For disagreement, find an affirmative conflict rather than an issue one passage does not address.
4. When applying one author’s argument to the other, preserve that author’s stated assumptions and limits. Do not invent a reply based only on the topic.

Check your work: Require evidence from both passages; lack of a statement is not the same as rejection.