Decision Making Bias: Survivorship
5 min read
fairly easy
Learn and practice avoiding Survivorship Bias with exercises.
What is Survivorship Bias?

The concept in one sentence:

Only paying attention to those who survive or succeed can mislead you.

The concept in one quote:

Survivorship bias can become especially pernicious when you become a member of the 'winning' team. Even if your success stems from pure coincidence, you'll discover similarities with other winners and be tempted to mark these as 'success factors'. However, if you ever visit the graveyard of failed individuals and companies, you will realize that its tenants possessed many of the same traits that characterize your success. Rolf Dobelli

The concept in one image:

How I use it?

In order to better understand success, I look for the differences between what succeeded and what failed.


Example 1

The survival rate for a disease is pretty high.

Can an unhealthy person be confident that they will survive?




The correct answer is No.

The survival rate could be high for healthy people and low for unhealthy people.

Example 2

A commonly held opinion is that music from previous generations is better.

Is it true?



Neither, It's subjective.


The correct answer is No (but neither is fine too, people have different tastes).

The best music from previous generations survived and the bad music died out. This means that people are comparing the best music from previous generations with the current music of today (good and bad).


Exercise 1

Bill Gates, Mark Zuckerberg, Michael Dell, Steve Jobs, Ralph Lauren, and Gabe Newell dropped out of college and later became billionaires. Inspired by this pattern, your cousin wants to drop out of college and launch his own company.

Should your cousin drop out?



Exercise 2

The army wants to reduce aircraft casualties by reinforcing certain parts. While studying returning aircraft (those who came back safely), they see the following:

Wings - 80 bullet holes on average

Tail - 40 bullet holes on average

Engine - 5…
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