Eivastausvääristymä

Eivastausvääristymä, also known as survivorship bias, is a logical error where one overemphasizes individuals or groups that have survived a process and overlooked those that did not because of their lack of visibility. This bias can lead to flawed conclusions and poor decision-making because the sample observed is not representative of the whole population.

The phenomenon is often illustrated by historical examples. During World War II, Abraham Wald famously analyzed where Allied bombers returned from combat with bullet holes. He reasoned that the areas *without* bullet holes were the most critical to reinforce because bombers hit in those locations likely never made it back. This counter-intuitive approach, focusing on the survivors' damage to infer the vulnerabilities of the non-survivors, prevented a common mistake of reinforcing areas that were already proven to be survivable.

Survivorship bias can appear in many contexts. In business, focusing only on successful startups might lead to ignoring the vast number of failed ventures, obscuring the true risks and challenges involved. In education, looking only at students who graduate and succeed might not reveal the underlying reasons why others drop out. In personal development, admiring the achievements of famous individuals without considering the countless others with similar efforts who did not achieve such fame can create unrealistic expectations. Recognizing and actively compensating for survivorship bias is crucial for accurate analysis and informed judgment.