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The tree

Twenty-one skill nodes, each with its own landing page. Eleven core LR question types, three meta-LR (about the argument's structure or speakers), seven Reading Comprehension. Click any row to see its sub-patterns.

Logical Reasoning · core (11)

• NANecessary assumption4 sub-patterns

  • Chain-link bridgeX causes Y, Y causes Z, therefore X causes Z. The NA secures the Y-to-Z link regardless of how Y was produced.
  • Modal qualifierThe argument leans on a word like "must," "could," or "always." The NA pins the modality to this case.
  • Bridge termA word in the conclusion is missing from the premises. The NA introduces it so the conclusion follows.
  • Alternative-cause exclusionThe argument names one cause. The NA rules out a competing cause that would explain the same evidence.
• SASufficient assumption4 sub-patterns

  • Bridge termA word in the conclusion is missing from the premises. The SA introduces it and connects the two.
  • Universal premiseA universal claim of the form "Any X is Y" or "All X are Y" that, combined with the premises, forces the conclusion.
  • Conditional chainA conditional of the form "If X, then Y" that links a premise to the conclusion. Often the answer extends a partial conditional already in the argument.
  • Quantifier matchThe premises use one quantifier (some, most, all) and the conclusion uses another. The SA closes the gap by introducing the matching quantifier.
• STStrengthen4 sub-patterns

  • Reinforces the causal linkWhen an argument claims X causes Y, the strengthener confirms the causal mechanism. Often by ruling out coincidence or by showing X-Y co-occur in additional cases.
  • Eliminates a counter-causeWhen an alternative explanation is plausible, the strengthener rules it out. The argument now stands without competition.
  • Provides a parallel caseWhen the argument generalizes from a sample, the strengthener confirms the sample resembles the target. The analogy holds.
  • Adds confirming evidenceWhen the argument rests on one piece of evidence, the strengthener supplies a second that points the same way.
• WKWeaken4 sub-patterns

  • Alternative causeWhen the argument claims X causes Y, the weakener supplies a different cause that could explain Y just as well. The original causal claim now competes.
  • Counter-evidenceWhen the argument rests on a piece of evidence, the weakener provides counter-evidence. Often timing-based: the effect appeared before the supposed cause.
  • Reversed correlationWhen the argument assumes X causes Y, the weakener suggests Y might actually cause X. The correlation is real, the direction is wrong.
  • Sample biasWhen the argument generalizes from a sample, the weakener shows the sample is unrepresentative. The generalization fails.
• FLFlaw4 sub-patterns

  • Necessary vs sufficientThe argument treats a necessary condition as if it were sufficient (or vice versa). "X is required for Y" is read as "X guarantees Y." The conclusion overshoots.
  • Correlation vs causationThe argument observes that X and Y co-occur and concludes that X causes Y. The argument fails to consider an alternative cause, reverse causation, or coincidence.
  • EquivocationThe argument uses a key term in two different senses. The conclusion follows only if the term is held to one sense, but the premises use the other.
  • Hasty generalizationThe argument generalizes from too few cases or an unrepresentative sample. The conclusion outruns the evidence.
• INInference4 sub-patterns

  • Must-be-true deductionThe statements together entail the answer with certainty. The answer cannot be false given the premises. No outside information is used.
  • Modal-qualifier inferenceThe statements use hedged language ("most," "some," "rarely," "could"). The right answer respects the modals in the premises. Distractors strengthen or weaken the modals without warrant.
  • Partial-overlap inferenceTwo statements share a term. The overlap lets you combine them to produce a new true statement. The right answer names what lies in the intersection.
  • Conditional chainA series of conditionals ("If A, then B; if B, then C") that can be chained into a new conditional ("If A, then C"). The right answer is the terminal step in the chain.
• PRPrinciple4 sub-patterns

  • Principle-supports-argumentYou are given a specific argument and asked to find a general principle that supports or justifies it. This acts like Strengthen. The principle makes the argument's reasoning more defensible. The right answer is abstract and general.
  • Case-matches-principleYou are given a general principle and asked which specific case falls under it. This acts like Sufficient Assumption. You test each choice against the principle's conditions to see which satisfies them.
  • Principle-identifies-flawYou are given an argument and asked which principle shows what is wrong with it. This acts like Flaw. The principle names the error; the argument commits the error.
  • Principle-justifies-judgmentYou are given a judgment (a conclusion) and asked which principle justifies reaching it from a stated situation. The right answer is the general rule that connects the situation to the judgment.
• PXParadox5 sub-patterns

  • Browsing-only trafficNew visitors come for a non-book reason and do not purchase books, so traffic rises while sales stay flat.
  • Temporal displacementThe new traffic arrives at times when book buyers are absent, leaving total book-buyer count unchanged.
  • Category offsetGains in one product or customer segment are cancelled by equal losses in another, masking the net effect.
  • External-force cancellationA concurrent external factor suppresses sales independently of the traffic change, producing a net-zero result.
  • Measurement artifactThe two metrics are measured differently or over different populations, making the apparent contradiction a data artefact rather than a real one.
• PAParallel reasoning4 sub-patterns

  • Same logical formThe valid argument in the stimulus uses a specific deductive or inductive structure. The right answer uses the identical structure with different content.
  • Same flawThe stimulus commits a named logical error. The right answer commits the same error in a different domain. Both the error type and its direction must match.
  • Valid deductive parallelThe stimulus argument is deductively valid. The right answer is also deductively valid using the same conditional or categorical structure.
  • Conditional parallelThe stimulus contains an explicit conditional ("If X, then Y"). The right answer uses the same conditional form, chained in the same direction.
• MPMain point4 sub-patterns

  • Conclusion at startThe main conclusion is stated in the first sentence; the remaining sentences are premises. Signal words: "therefore," "so," "thus" are absent at the start; the premises follow with "because," "since," "given that."
  • Conclusion at endThe main conclusion appears in the last sentence, after all the premises have been laid out. Signal words: "therefore," "so," "thus," "hence," "consequently" typically precede the final sentence.
  • Sub-conclusion trapThe argument contains an intermediate claim that is supported by some premises and that in turn supports the main conclusion. The sub-conclusion often appears late in the argument, making it easy to mistake for the main point.
  • Nested argumentTwo or more layers of conclusion-support chains. The inner layer produces a sub-conclusion. The outer layer uses that sub-conclusion as a premise to reach the true main conclusion.
• MORMethod of reasoning5 sub-patterns

  • Premises-and-conclusion descriptionThe argument states evidence and draws a conclusion from it. The MOR answer names both: "uses evidence of X to conclude Y." The most common sub-pattern.
  • Counter-argument responseThe argument acknowledges an opposing claim and then responds to it. The MOR answer names both the concession and the response: "concedes X but argues that Y."
  • Analogy deploymentThe argument supports its claim by drawing a parallel to another case. The MOR answer names this: "supports the conclusion by drawing an analogy to X."
  • Evidence-to-claim descriptionThe argument cites a specific example or data point and uses it to support a broader generalization. The MOR answer names the inductive move.
  • Most-useful-to-evaluate scanArgument Evaluation stems ask which fact would most help evaluate the argument. The method is to identify the argument's weakest inferential link, then scan choices for a fact that bears directly on that link. Argument Evaluation is taught as a sub-section of Method of Reasoning because both skills require mapping argument structure before selecting an answer.

Logical Reasoning · meta (3)

Questions about the argument itself: the role of a claim, the point at issue between two speakers, the point they agree on.

• ROLERole in argument5 sub-patterns

  • PremiseA fact or assertion offered as direct support for the main conclusion. Removing it weakens the argument.
  • Sub-conclusionA statement that is supported by at least one premise and itself supports the main conclusion. It is both a conclusion and a premise depending on which direction you look.
  • Main conclusionThe final claim the entire argument is built to support. It is not a premise for anything else in the argument.
  • Opposing viewA position the arguer does not hold, presented to set up a refutation or contrast. The arguer neither accepts nor endorses it.
  • Concession-then-distinguishThe arguer acknowledges a counter-consideration that appears to undercut the conclusion, then defuses it by showing it does not apply to the case at hand. The concession is not a premise for the main conclusion. It is a defensive move.
• PDPoint of disagreement4 sub-patterns

  • Direct contradictionSpeaker 1 asserts X. Speaker 2 explicitly denies X, or asserts not-X. Both have stated positions. The disagreement is explicit.
  • Implied contradictionSpeaker 1 asserts X. Speaker 2 does not deny X directly but commits to a position that logically requires not-X. The disagreement is derivable from what each speaker says.
  • Scope disagreementBoth speakers agree about some cases but disagree about whether the claim holds universally or only in limited cases. The disagreement is about the scope, not the direction.
  • Shared premises, different conclusionsBoth speakers cite similar evidence but draw opposite conclusions from it. The disagreement is not about the facts but about what the facts imply.
• POAPoint of agreement4 sub-patterns

  • Direct shared endorsementBoth speakers explicitly state or assert the same claim. No inference is required. Both positions are readable from the text of each speech.
  • Implied shared endorsementNeither speaker states the claim outright, but both speakers commit to positions that logically require the claim to be true. The agreement is derivable from what each speaker says.
  • Agree on grounds but not conclusionBoth speakers accept the same evidence or premise but draw different conclusions from it. The agreement is limited to the shared factual ground. Picking the conclusion either speaker draws is the trap.
  • Agree on conclusion but not groundsBoth speakers reach the same conclusion but for different reasons. The agreement is on the conclusion, not the path to it. Picking one speaker's grounds as the shared claim is the trap.

Reading Comprehension (7)

• RC-MAINRC main point4 sub-patterns

  • Thesis identificationThe passage states a single central claim. The right answer is that claim, paraphrased. Distractors are sub-claims used to support it.
  • Author's stance vs others'The passage describes one or more views and the author takes a side. The right answer captures the author's side, not the views the author opposes.
  • Comparative analysisThe passage weighs alternatives without choosing. The right answer captures the act of weighing, not one alternative.
  • Single-event focusThe passage describes one phenomenon and its significance. The right answer captures both the phenomenon and the significance.
• RC-PURRC primary purpose4 sub-patterns

  • Describe/informThe author conveys information without arguing for a position. The passage presents a situation, a process, or a set of facts. The right answer starts with "describe" or "explain." Distractors often substitute "argue" or "defend."
  • Advocate/argueThe author takes a position and supports it with evidence or reasoning. The right answer starts with "argue" or "defend." Distractors often substitute "describe" or "evaluate," underselling the author's assertiveness.
  • Critique/evaluateThe author examines a position or practice and identifies its weaknesses or merits. The right answer starts with "critique," "assess," or "evaluate." Distractors often frame the passage as pure description when the author takes a clear stance on what is being evaluated.
  • Compare/contrastThe author sets two or more positions or approaches side by side. The right answer captures the act of comparison. Distractors often credit only one side of the comparison, missing the structural device.
• RC-DETRC detail4 sub-patterns

  • Quote verificationThe right answer matches a specific phrase from the passage. Distractors swap a key word. Match the noun, the verb, the qualifier; not just the topic.
  • Paraphrase matchThe right answer rewords a passage statement accurately. Distractors paraphrase but shift meaning. Read for what the paraphrase preserves and what it changes.
  • Off-by-one detailThe right answer captures one specific detail. Distractors mix two adjacent details (e.g., the passage states X about weekday and Y about weekend; a distractor states X about weekend).
  • Implication vs assertionThe passage implies something. A distractor asserts it. Detail rewards what the passage states, not what it leaves to inference. Inferences belong on Inference questions.
• RC-INFRC inference4 sub-patterns

  • Modal-qualifier inferenceThe passage uses a modal cue ("could," "must," "always," "rarely"). The right answer respects the modal. Distractors swap the modal for a stronger or weaker one.
  • Author-attitude inferenceThe passage signals the author's stance through word choice or framing. The right answer captures that stance. Distractors invert it or overstate it.
  • Cross-paragraph inferenceThe right answer combines information from two paragraphs the test-taker must connect. The passage states neither half alone; the inference lives in the join.
  • Negation inferenceThe passage tells you what the author rejects. The right answer states something the author would deny if asked. Distractors are merely unaddressed.
• RC-ATTRC author attitude5 sub-patterns

  • Strong endorsementThe author argues that the subject is clearly correct or clearly admirable, without qualification. The passage uses assertive, positive language and does not introduce doubt.
  • Qualified endorsementThe author admires or approves of the subject but withholds full endorsement. Hedges like "worth noting," "unusual," or "an exception" signal this stance. The most commonly tested sub-pattern.
  • Neutral descriptionThe author reports without evaluating. No stance is visible. Word choice is flat and no passage sentence commits to a judgment. This is often a distractor on passages where the author is actually mildly positive.
  • Qualified skepticismThe author doubts or questions the subject but does not condemn it. Language like "it is unclear whether," "the evidence does not yet support," or "has not been demonstrated" marks this stance.
  • Strong skepticismThe author is plainly critical or dismissive. The passage uses language like "fails to," "is undermined by," or "cannot account for." This stance requires consistent negative framing across the passage, not a single critical sentence.
• RC-FUNCRC function4 sub-patterns

  • Structural-support functionThe element provides evidence or reasoning that directly supports the passage's main argument. It moves the argument forward. The right answer names it as support, evidence, or substantiation for the overall thesis.
  • Illustrative-example functionThe element gives a concrete case that clarifies or demonstrates a more abstract principle or claim made elsewhere in the passage. The right answer names it as an example, illustration, or application.
  • Concession functionThe element acknowledges a contrary view, an exception, or a limitation. The author includes it to show awareness of the opposing position before returning to the main argument. The right answer uses words like "concedes," "acknowledges," "notes a limitation," or "recognizes an objection."
  • Qualification functionThe element narrows or restricts a claim made elsewhere in the passage. It does not contradict the claim; it specifies under what conditions the claim holds. The right answer names the restricting or narrowing role.
• RC-COMPRC comparative passages7 sub-patterns

  • Relationship between passagesThe question asks how the two passages relate overall: agreement, disagreement, one extends the other, one rebuts the other, or one provides evidence the other interprets differently.
  • Inference across bothThe right answer combines commitments from both passages. Neither passage alone supports the answer. The trap is an answer supported by one passage but contradicted or unaddressed by the other.
  • Function of element in bothA specific piece of evidence or claim appears in both passages. The question asks what function it serves in each. A piece of evidence can serve opposite functions in two passages that take opposing positions.
  • Comparative main pointThe question asks for the main point of each passage, or asks which choice captures what both passages are about. Both skeletons must match the credited answer.
  • Author attitude across bothThe question asks about one author's attitude toward the subject, toward a specific claim, or toward the other passage. Attitude is signaled by word choice, by what the author endorses or qualifies, not by what the author merely describes.
  • Primary purpose across bothThe question asks the primary purpose of each passage or asks which choice describes both authors' purpose. Purpose answers describe what the author is doing (arguing, analyzing, rebutting, illustrating) rather than what the passage is about.
  • Analogy/application to bothThe question presents a scenario and asks which passage author would view it more favorably, or how the scenario applies to the arguments of both. Map the scenario against each skeleton before evaluating choices.

The trap canon

20 closed-list trap codes our content vault uses to tag distractor diagnoses. The same code means the same thing across every node. Inventing a new code is a hard validation failure.