Quick Summary (Simple Explanation)

Survivorship bias is a mistake in thinking where we only focus on people or things that succeeded and ignore those that failed. When we do this, we may reach the wrong conclusion about what really leads to success.

Why Is Survivorship Bias a Problem?

If we only look at successful results, we miss important information about failures. This can make us overconfident, cause bad decisions, and lead to wasted time and money. To understand the true picture, we must also think about what we cannot see.

Famous Example: World War II Airplanes

One of the most famous examples of survivorship bias comes from World War II. Engineers studied the bullet holes on returning airplanes and planned to add armor where they saw the most damage. However, a mathematician pointed out that they should instead reinforce the areas with no damage. Planes hit in those areas never returned—so their data was missing.

This showed that focusing only on surviving planes would lead to the wrong decision.

Everyday Examples of Survivorship Bias

• Success stories in business: We hear about companies that became rich, but not about the many that failed.
• Diet success stories: We see people who lost weight, but not those who tried and failed.
• Top students’ study methods: Their methods may not work for everyone.

Why Does Survivorship Bias Happen?

1. Successful cases are easier to see.
2. Failed cases often disappear from records.
3. People like positive and inspiring stories.

How Can We Avoid Survivorship Bias?

1. Ask whether the data includes failures.
2. Look for missing information.
3. Compare multiple groups, not just one.
4. Use original and reliable data sources.

Think About It (Practice Questions)

1. If you copy the study habits of top students, will you always get the same results? Why or why not?
2. When you hear a success story online, what questions should you ask to check for survivorship bias?

Conclusion: Always Think About What You Cannot See

Survivorship bias can easily mislead us. By remembering that hidden failures also exist, we can make better, more realistic decisions. Learning this way of thinking at a young age helps develop strong critical thinking skills.