Assuming correlation means causation
"The Causation Confusion"
The Mistake in Action
A scatter graph shows positive correlation between number of fire engines at a fire and the damage caused. Conclusion: Fire engines cause more damage.
Wrong: More fire engines must cause more damage.
Why It Happens
Students assume that if two things are related (correlated), one must cause the other. This is a fundamental logical error.
The Fix
Correlation ≠ Causation
The fire engines don't cause the damage. The hidden variable is the size of the fire:
- Bigger fires cause more damage
- Bigger fires need more fire engines
Both variables are affected by a third factor.
Always ask: Could there be another explanation? Is there a hidden variable?
Spot the Mistake
Can you identify where this student went wrong?
Positive correlation between fire engines and damage
Therefore fire engines cause more damage
Click on the line that contains the error.
Related Topics
Learn more about the underlying maths: