cause · statistics
Ice cream and drowning
Ice cream sales and drowning both increase in summer.
Ice cream sales and drowning both increase in summer. They rise together, but one does not cause the other.
Ice cream
Drowning
Ice cream sales and drowning both rise in summer.
The sun is the season. The two stacks are the two counts.
Rising together shows a link. It does not show the direction or the real cause. Only changing one thing on purpose can help reveal what is actually happening. Correlation does not imply causation.