Survivorship Bias

[youarenotsosmart.com/2013/05/2...](http://youarenotsosmart.com/2013/05/23/survivorship-bias/)

You Are Not So Smart is back with a new post on Survivorship Bias. If you don’t know YANSS, click and read until your curiosity is quenched.

This blog introduced me to cognitive biases and there is not a single day that passes when I do not think of all the things I learned on this website. 

Simply put, survivorship bias is your tendency to focus on survivors instead of whatever you would call a non-survivor depending on the situation. Sometimes that means you tend to focus on the living instead of the dead, or on winners instead of losers, or on successes instead of failures. In Wald’s problem, the military focused on the planes that made it home and almost made a terrible decision because they ignored the ones that got shot down.

It is easy to do. After any process that leaves behind survivors, the non-survivors are often destroyed or muted or removed from your view. If failures becomes invisible, then naturally you will pay more attention to successes. Not only do you fail to recognize that what is missing might have held important information, you fail to recognize that there is missing information at all.