Survivorship Bias
Successes are visible; failures are hidden.
Explanation
We naturally focus on successful examples because failures often disappear from view or don't get talked about. During World War II, the military wanted to add armor to planes where they saw bullet holes. Statistician Abraham Wald pointed out the flaw: they should armor where they didn't see holes, because planes hit in those spots didn't make it back to be examined.
Real-World Example
'College dropouts like Gates and Zuckerberg became billionaires!' But millions of dropouts struggle in poverty—they don't write books. 'This startup pivoted 3 times and succeeded!' But 99% that pivot 3 times die—and delete their blogs. Gym in January: See fit people, think gym works. Don't see the 90% who quit by February.
How to Apply
Always ask: Where are the bodies? What's the base rate (% that actually succeed)? Who isn't here to tell their story? Before copying success stories: Find failures who tried the same strategy. Remember: advice from lottery winners about winning the lottery is worthless. Sometimes success is despite the strategy, not because of it.