“Correlation is not causation”
We say:
“Correlation is not causation.”
This is shorthand for a more meaningful statement,
“Data alone cannot demonstrate causation. Doing that takes knowledge about how the system you’re studying works.”
Correlation is causation
More precisely: When we see a genuine correlation between to variables, there must exist a causal path connecting them. That path can be any of the following
Confounding
How to deal with confounding: Block the path through C.
But don’t block mediators.
