Correlation and Causation

Do you too become a little frustrated at the increasing list of foods and activities which are good/bad for us? And if you delve a little, you discover tiny sample sizes, poorly constructed trials and a simple confusion between correlation and confusion?

The Classic Warning

A strong correlation does not prove causation. Otherwise, we’d conclude that carrying lighters causes lung cancer.

The Exam Question

A study shows that students who revise more get higher grades. Does revision cause good grades?

Answer: Probably. But the exam board would like you to say: “There may be other variables involved.”