When Two Things Rise Together
Ice cream sales and sunburn both climb in summer, but neither causes the other: the weather drives both. That hidden third factor is called a confounder, and it sits behind many claims that sound convincing, like 'people who do X are healthier' or 'teams that use Y perform better'.
Questions to Ask Before You Believe the Link
- Could the cause run the other way round?
- Is there a third thing that could be driving both?
- Could it be coincidence, especially with a small sample?
Hold the Claim Lightly
A scientist's first move isn't to reject the connection. It's to ask what else could explain it.