Correlation vs. Causation on the LSAT: When Is It a Flaw?
"Confuses correlation with causation" is one of the most common LSAT flaw answers. Learn the three alternatives every causal argument ignores and how to spot the trap fast.
2026-06-01 · 7 min read
The pattern the LSAT loves
A huge share of LSAT arguments take this shape: two things are correlated (they rise and fall together, or one followed the other), and the author concludes that one caused the other. This is the single most tested reasoning move on the test, and it is almost always vulnerable.
The argument is not necessarily wrong — but it is unsupported, because correlation is consistent with several explanations besides the one the author picked.
The three alternatives every causal claim ignores
1. Reverse causation: maybe B caused A, not A caused B.
2. A third common cause: maybe some factor C caused both A and B, so they move together without either causing the other.
3. Coincidence: with enough variables, things line up by chance.
When you see a causal conclusion drawn from a correlation, these three are your menu. Strengthen answers rule them out; weaken answers raise one of them.
Worked example
"People who take daily walks report lower stress. Therefore, walking reduces stress."
Reverse causation: maybe low-stress people are simply more likely to find time to walk. Third cause: maybe people with flexible jobs both walk more and have less stress. Either possibility weakens the argument without denying that walking and low stress go together.
How to use this on test day
The moment a stimulus moves from "X and Y are associated" to "X causes Y," flag it. On a flaw question, the answer is often phrased as "the argument overlooks the possibility that another factor explains both" or "mistakes correlation for causation." On strengthen and weaken questions, look for answers that close or open one of the three alternatives.
Verbloom highlights this premise-to-conclusion jump in causal arguments so the move stops sneaking past you.
Frequently asked questions
Is every causal argument on the LSAT flawed?
Not inherently, but causal arguments built only on a correlation are vulnerable because they ignore reverse causation, a common cause, and coincidence. The test relies on this gap constantly.
How do I strengthen a causal argument?
Rule out the alternatives: show the effect did not precede the cause, that no third factor explains both, or that the relationship holds when other variables are controlled.
What words signal a causal conclusion?
"Caused," "led to," "produced," "is responsible for," "because of," and "results in" all flag a causal claim worth scrutinizing.
Related Verbloom guides
Sources
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