Probability and Statistical Biases
Selection bias
Drawing conclusions from a non-representative sample.
What Is Selection bias?
Selection bias is a thinking trap where drawing conclusions from a non-representative sample.
How It Tricks You
It can make noisy, incomplete, or poorly framed data feel more meaningful than it is.
Real-World Example
A gym survey misses people who quit because only current members answer.
Seen Online As
- The chart looks convincing before I check the sample.
- One number is being asked to carry the whole argument.
- The data point feels cleaner than the data really is.
What To Ask Instead
Who was included or excluded?
Related Thinking Traps
Common Situations
Quick FAQ
What is Selection bias?
Drawing conclusions from a non-representative sample.
What is an example of Selection bias?
A gym survey misses people who quit because only current members answer.
How do I spot Selection bias?
Who was included or excluded?