Quick Definition: Survivorship Bias is the mental error of only learning from successful projects or people and overlooking those that failed.
What is Survivorship Bias?
Survivorship Bias is the mental error of only learning from successful projects or people and overlooking those that failed. When we don’t examine failures, we draw conclusions and make decisions with incomplete information (which can lead to more failure).
One of the most brilliant examples of identifying this bias comes from World War II when statistician Abraham Wald was working for the U.S. military. His job was to figure out where planes should have their armor reinforced to avoid getting shot down.
The military’s initial efforts weren’t successful, and Wald knew why.
When surviving planes returned to base after a battle, military engineers looked at where they’d been shot. They then reinforced the areas where they found the most bullet holes. But there was a big problem with this strategy.
The engineers only saw planes that had returned with survivable damage. The *crashed* planes didn’t return because they were shot somewhere that downed the plane. So Wald proposed a new strategy: “Reinforce the areas where the surviving planes have NOT been shot. Those are the places where the downed planes were fatally damaged.”
How to Spot Survivorship Bias in Real Life
It’s really easy to spot examples of Survivorship Bias in real life, once you train yourself to see it:
- Corporate Cultures: The aggressive, high-performance cultures of companies like Netflix and Amazon are often lauded. However, this overlooks the countless organizations where this behavior has led to burnout, high turnover, or even business failure.
- Career Choices: Stories of high school dropouts becoming millionaire streamers and people leaving stable jobs to launch unicorn startups are inspirational. But focusing on these outliers (and using their success stories to make major life decisions) ignores the people who took the same risks but didn’t succeed.
- Business Strategies: The flashy success stories of industry disruptors can overshadow the value of steady, sustainable development over decades (which is how most successful companies are built).
It doesn’t mean we can’t be inspired by success stories. We just need to make sure we have the whole story (did that successful streamer have a trust fund, or did that hot new actor have a famous parent in entertainment?) before we use these stories to make decisions in our own lives.
How to Avoid Survivorship Bias in Decision Making
To make better decisions, we need to avoid Survivorship Bias. To identify if you’re falling victim to this thinking trap, start by asking yourself three questions:
- 🧠When I look back to see what’s gone right, have I also looked at what’s gone wrong?
- 🧠Am I accounting for the features, tendencies, or characteristics of failure and success?
- 🧠What features or choices do success and failure have in common?
The Bottom Line
Survivorship Bias can lead us to draw incomplete or incorrect conclusions by focusing only on success stories. By recognizing and addressing this bias, we can get a more nuanced understanding of what factors are actually causing success and failure. Whether in military strategy, business, or personal decisions, we need to learn lessons not just from the winners, but the losers as well.