The big idea
🔗
Together is not because
Two things moving in step tells you something is going on — not that one is causing the other.
Critical Thinking · Lesson 6
Correlation vs Causation
beginner⏱ 15 min · 9 cards
The hidden third factor
What a confounder does
Hot weather drives both ice cream and swimming. Neither touches the other.
Rule these out first
Three innocent explanations
Tap each.
Try it
Confounder Finder
“Ice-cream sales rise when drownings rise.”
What best explains the pattern without one causing the other?
A correlation is a reason to investigate, never a conclusion.
Diagnose why each pattern is not evidence of cause.
Key term
What would settle it?
How do you actually show cause?
tap to reveal ↻
Intervention
Change X deliberately and watch Y — a randomized controlled trial. Where that is impossible, cause is built from mechanism, dose-response, and ruled-out confounders across many studies.
Nuance
Reading headlines
Think like a Maester
If the study observed people rather than intervening, the honest phrasing is “is associated with”. Anything stronger was added later.
Recap
Key takeaways
- ✓Correlation describes a pattern; causation claims a mechanism.
- ✓Confounding, reverse causation, and coincidence each produce correlation without cause.
- ✓Spurious correlations are inevitable when enough data is compared.
- ✓Establishing cause needs temporal order, mechanism, ruled-out confounders, dose–response, or intervention.
- ✓Observational studies support "associated with," not "causes."
Quick check
What best describes critical thinking?
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