Concept Library

Every core LSAT concept, explained.

Deep-dive explainers for the concepts that appear on every LSAT: assumptions, causal reasoning, conditionals, structural reading, and more.

Logical Reasoning

Necessary vs. Sufficient Assumption: The Definitive LSAT Explainer

A necessary assumption must be true for the argument to hold — negate it and the argument collapses.

Logical Reasoning

Causal Flaws on the LSAT: Every Pattern, Every Trap

Causal flaws account for roughly 30% of all Flaw and Weaken questions on the modern LSAT.

Logical Reasoning

LSAT Conditional Reasoning: Contrapositives, Chains, and Common Errors

'If A, then B' has one valid inference: the contrapositive — if not B, then not A.

Reading Comprehension

LSAT Reading Comprehension: The Passage-Mapping Method

Every LSAT passage has four extractable elements: main point, author's viewpoint, counterview, and scope.

Logical Reasoning

Parallel Reasoning and Parallel Flaw: A Structural Approach

Parallel Reasoning is about structural form, not subject matter — treat the stimulus as an equation to be matched.