Ice cream sales and sunburn rise together. Ice cream does not cause sunburn.
Direct answer
Correlation shows that two variables move together. Causation means that changing one produces a change in the other. A third factor, a confounder, can cause both, as hot weather drives both ice cream sales and sunburn. Randomised experiments are the best way to show cause.
Why correlations mislead
- Confounders: a hidden driver.
- Coincidence: random patterns in many variables.
- Reverse causation: the effect may cause the "cause".
How to be careful
- Ask what else could explain the link.
- Check whether the cause came before the effect.
- Look for experiments or natural experiments.
- Be cautious with language: "is associated with", not "causes".
In Python
df[["hours", "score"]].corr()
Where Teyro fits
Teyro's Data Science for Beginners course turns this into short lessons you can play in a few minutes a day. It has 50 lessons, and you can start free.
The bottom line
A correlation is a clue, not a conclusion.
