Argument Structure & Keyword Indicators
What You Need to Know
Argument structure is the skeleton of nearly every LSAT Logical Reasoning stimulus: the author gives premises (support) to justify a conclusion (the claim they want you to accept). Your job is to quickly label what each sentence/claim does.
Core roles (know these cold)
- Conclusion: the main point the author is trying to prove.
- Premise: evidence/reasons offered to support the conclusion.
- Subconclusion / intermediate conclusion: a claim that is supported by earlier premises and then used to support the main conclusion.
- Background/context: information that sets the scene but isn’t used as support.
- Counterpremise: a consideration against the author’s conclusion (often introduced to be answered).
- Rebuttal: the author’s response that neutralizes the counterpremise.
- Concession: “Even if…” or “Although…” acknowledgement that doesn’t change the author’s bottom line.
Why keyword indicators matter
The LSAT often gives you indicator words that flag which role a statement plays:
- Conclusion indicators (e.g., “therefore”) point to what’s being proved.
- Premise indicators (e.g., “because”) point to support.
- Contrast indicators (e.g., “however”) often mark a pivot: the author’s real view frequently comes right after.
Critical reminder: Keywords are clues, not guarantees. The only thing that makes a statement the conclusion is that the rest of the argument is trying to establish it.
When you use this skill
Basically always in LR, but especially for:
- Main Conclusion / Main Point questions
- Method of Reasoning / Argumentative Strategy questions
- Flaw and Strengthen/Weaken (you must know what’s premise vs conclusion)
- Identify the role (statement plays which role?) question stems
Step-by-Step Breakdown
Use this quick workflow to “map” an argument in under 20 seconds.
1) Find the author’s main conclusion
- Scan for conclusion indicators (therefore, thus, so, hence, consequently, etc.).
- If none: apply the “So what?” test: which claim is the point?
- Check for recommendations (should/ought/must) or predictions (will/likely) — these are often conclusions.
Micro-check: If you remove a candidate conclusion, do the remaining sentences look like they’re trying to support it? If yes, you’ve likely found it.
2) Mark the support (premises)
- Look for premise indicators (because, since, for, given that, after all).
- Ask “Why should I believe the conclusion?” The answers are premises.
- Treat facts/stats/studies/examples as likely premises if they’re used to justify something.
3) Watch for shifts: counterpremise → rebuttal
- Spot contrast words (but, however, yet, although, nevertheless).
- Decide whether the contrast introduces:
- a counterpremise (a challenge the author acknowledges), or
- the author’s conclusion (common pattern: other view first, author second).
- If the author then says “still,” “nevertheless,” or “but,” that often signals a rebuttal followed by the real conclusion.
4) Check for intermediate conclusions (chains)
Some arguments are two-layer:
- Premises → subconclusion → main conclusion
How to spot it:
- A sentence has a conclusion indicator, and it then gets used as support for a later claim.
5) Do a 5-second “structure summary”
In your head, reduce it to:
- “Because [premise(s)], therefore [conclusion].”
- If there’s a concession: “Although [concession/counter], because [support], therefore [conclusion].”
Worked mini-example (annotated)
Stimulus:
“Although the city added more buses last year, commute times did not improve. After all, traffic from new ride-share vehicles increased sharply. Therefore, the city should limit ride-share permits.”
Map:
- Concession/contrast: “Although the city added more buses…”
- Premise (support): “After all, traffic from new ride-share vehicles increased…”
- Conclusion (recommendation): “Therefore, the city should limit ride-share permits.”
Key Formulas, Rules & Facts
(There aren’t math formulas here; these are your structure rules and indicator lists.)
Conclusion indicators (common)
| Indicator | What it signals | Notes / traps |
|---|---|---|
| therefore, thus, hence | conclusion follows | Often the main conclusion, but can mark an intermediate conclusion in a chain |
| so, consequently, as a result | conclusion or prediction | “So” can be casual in dialogue; confirm with the “So what?” test |
| it follows that | conclusion | Strong indicator |
| proves/shows/demonstrates that | conclusion | Sometimes the author is claiming proof; still test support |
| clearly, obviously | conclusion emphasis | Not a guarantee of validity |
| should/ought/must | recommendation conclusion | Usually needs a value/goal premise (explicit or assumed) |
| likely/probably/will | predictive conclusion | Often built from trend data or causal claims |
Premise indicators (common)
| Indicator | What it signals | Notes / traps |
|---|---|---|
| because | premise | Occasionally appears inside a conclusion phrasing (“The reason is that…”) — still indicates support content |
| since | premise | Can be time (“since 2010”) vs reason (“since it rained…”) |
| for | premise | Can be preposition (“for three years”) vs reason (“for the policy failed…”) |
| given that | premise | Strong support indicator |
| after all | premise (often late) | Frequently comes after the conclusion to justify it |
| as indicated by | premise | Points to evidence like surveys/data |
| inasmuch as | premise | Rare but clear |
Contrast / pivot indicators (high-yield)
| Indicator | What it signals | What to do |
|---|---|---|
| but, however, yet | pivot | The author’s main point often comes right after |
| although, even though | concession | The clause after these often is not the author’s final point |
| nevertheless, nonetheless, still | rebuttal / “despite that” | Often introduces the author’s real conclusion after acknowledging a counterpoint |
| despite, in spite of | concession | Treat as “even given this…” |
“Why” and “what supports what” rules
- Premises answer “Why?” about the conclusion.
- Conclusions answer “So what?” about the premises.
- If statement B is offered to justify statement A, then:
- B = premise, A = conclusion (even if A appears first).
Common structural patterns you should recognize
| Pattern | Typical wording | What it usually means |
|---|---|---|
| Conclusion first, support later | “[Conclusion]. After all, [premise].” | Don’t assume the first sentence is background; “after all” is your clue |
| Concession → author view | “Although [counter], [author conclusion].” | The “although” part is rarely the main conclusion |
| Counterpremise → rebuttal → conclusion | “Some say [counter]. But [rebuttal]. Therefore [conclusion].” | Map each role; rebuttal supports conclusion |
| Chain | “Thus [subconclusion]. Therefore [main conclusion].” | First “thus” can be intermediate, second is main |
Conditional / exception indicators (often shape structure)
These aren’t “premise vs conclusion” indicators, but they strongly affect how you parse claims.
| Keyword | Typical logical meaning (plain English) | Fast caution |
|---|---|---|
| if | introduces a sufficient condition | Don’t reverse it |
| only if | introduces a necessary condition | Many students flip this |
| unless | “if not” (introduces a necessary condition) | Often rewrite as “If not X, then Y” |
| until | can act like “unless” in rules | Pay attention to scope |
| except | creates an exception | Exceptions often appear in premises defining a rule |
Examples & Applications
Example 1: No keywords (use “So what?”)
Stimulus: “People who sleep fewer than six hours have higher accident rates. Night-shift workers often sleep fewer than six hours. Night-shift workers are more likely to have accidents.”
Map:
- Premise: fewer than six hours → higher accident rates
- Premise: night-shift workers often sleep fewer than six hours
- Conclusion: night-shift workers more likely to have accidents
Key insight: Even without “therefore,” the last sentence is what the first two are trying to establish.
Example 2: Intermediate conclusion (chain)
Stimulus: “The survey sample was drawn only from current customers. So the results do not represent the general public. Therefore, the ad campaign should not be targeted based on this survey.”
Map:
- Premise: sample only from current customers
- Subconclusion: results don’t represent general public
- Main conclusion: don’t target ad campaign based on survey
Key insight: The middle sentence is both a conclusion (from the sampling fact) and a premise (for the recommendation).
Example 3: Counterpremise + rebuttal
Stimulus: “Some claim that raising the minimum wage causes job losses. However, studies of recent increases show no decrease in employment. Thus, the claim is unsupported.”
Map:
- Counterpremise (opposing view): raising minimum wage causes job losses
- Premise/rebuttal evidence: studies show no decrease in employment
- Conclusion: the claim is unsupported
Key insight: “However” flags the author’s pivot away from the opposing view.
Example 4: “After all” premise placed after conclusion
Stimulus: “The committee’s decision was unfair. After all, it evaluated applicants using criteria that were never announced.”
Map:
- Conclusion: decision was unfair
- Premise: used unannounced criteria
Key insight: Many students mistakenly treat the first sentence as background. It’s the conclusion.
Common Mistakes & Traps
Assuming the first sentence is the conclusion
- Why wrong: LSAT often puts the conclusion second (or first with support after).
- Fix: Use the “So what?” and “Why?” tests; look for “after all” support after a claim.
Treating indicator words as automatic truth
- Why wrong: Words like “therefore” can mark an intermediate conclusion; “since” might be temporal.
- Fix: Confirm by checking whether other statements actually support that claim.
Missing the real conclusion after a contrast word
- Why wrong: Test writers love: “Some people think X. But Y.” The “but” side is usually the author.
- Fix: When you see however/but/yet, slow down and label roles explicitly.
Confusing a counterpremise with a premise
- Why wrong: “Although/Some say/It might seem” often introduces a view the author is not endorsing.
- Fix: Ask: “Is the author using this to support their point, or setting it up to knock down?”
Calling everything that sounds factual a premise
- Why wrong: Some facts are just background (context, timeline, definitions) unless used as support.
- Fix: Only label as premise if it helps answer “Why should I accept the conclusion?”
Forgetting that recommendations need a goal/standard
- Why wrong: “Should” conclusions usually rely on an (often unstated) value like safety, fairness, profit.
- Fix: When you see should, look for the goal the author is trying to achieve (even if implicit).
Missing “after all” and late-arriving support
- Why wrong: “After all” frequently introduces the key evidence.
- Fix: Train yourself: After all = because (most of the time).
Over-mapping conditional keywords as structure keywords
- Why wrong: “Only if/unless” affect logic, but they don’t automatically tell you premise vs conclusion.
- Fix: First label roles (premise/conclusion), then worry about conditional relationships.
Memory Aids & Quick Tricks
| Trick / mnemonic | What it helps you remember | When to use it |
|---|---|---|
| “So what?” test | Finds the conclusion when no indicators | Anytime the stimulus is just 2–4 plain sentences |
| “Why?” test | Finds premises (they answer “why believe the conclusion?”) | When multiple facts are listed and you’re unsure what supports what |
| “However = author” heuristic | After “however/but/yet,” the author’s view often appears | When stimulus opens with an opposing view or concession |
| “After all = evidence” | “After all” usually introduces support | When the conclusion appears before the justification |
| Spot the verbs: should / must / likely | These often mark conclusions (recommendation/prediction) | When you’re stuck between two candidate conclusions |
| Chain check: “Is this claim used again?” | Detects intermediate conclusions | When you see multiple conclusion indicators (thus/therefore) |
Quick Review Checklist
- Identify the main conclusion (what the author wants you to accept).
- Label premises by asking: “Why should I believe that conclusion?”
- Treat however/but/yet as a pivot: the author’s real stance often follows.
- Watch for after all introducing a key premise after a conclusion.
- Separate counterpremises (opposing considerations) from the author’s support.
- Check for intermediate conclusions: supported earlier, then used as support later.
- Remember: keywords guide you, but support relationships decide roles.
You don’t need to read faster—you need to label cleaner.