Fallacy · Bad evidence
Correlation is not causation
Also called: Cum hoc ergo propter hoc
Concluding that because two things go together, one causes the other.
What it is
Two things can rise and fall together because one causes the other, because the other causes the first, because a third thing drives both, or by chance. A correlation is a clue that something may be going on, not proof of which way it runs.
An example
Towns with more ice-cream sales have more drownings. Ice cream does not cause drowning; hot weather increases both.
How to spot it
Ask: could a third factor cause both? Could the cause run the other way?
How to answer it
“Interesting link. What else might explain both?”
When it is not a fallacy
Correlations from careful studies, especially experiments that control for other factors, can be strong evidence of causes.
Printable sheet of all fallacies
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A plain reference you can paste into notes or an essay:
Quest2Reason. “Correlation is not causation.” https://quest2reason.com/learn/ideas/fallacies/correlation-causation. Accessed 13 November 2026.