What are some famous examples of survivorship bias?

Let’s first understand what survivor bias is.

The concept of survivorship bias: "Survivorship bias" is a common statistical concept, which refers to only considering those individuals who "survived" in the study, while ignoring those who have been eliminated or The missing individuals lead to biased research results.

Famous example 1: Research on fighter aircraft during World War II.

This concept originally originated from the U.S. Air Force’s research on improving aircraft during World War II, and is also one of the most famous examples of survivor bias. The overview is as follows:

During World War II, in order to strengthen the protection of fighter aircraft, British and American military scientists discovered that after each air battle, the most hit areas of fighter jets returning to base were mainly on the wings on both sides. Therefore, scientists propose adding armor to the parts with the most bullet holes to improve the aircraft's defense capabilities.

This suggestion was rejected by Abraham Walder, a statistician of the US Army. He pointed out that these bombers riddled with holes were "survivors" who successfully flew back from the battlefield, so their fuselage The bullet holes on the plane are not fatal to the aircraft. The most correct way to save the lives of the pilots is to study the bombers that were hit and crashed. Only by studying the "unlucky ones" who failed to return successfully can the most vulnerable points of these aircraft be found and reinforced with armor.

Abraham Wald’s advice was later adopted by the military and saved the lives of thousands of pilots. This is the most famous example of survivorship bias.

The researchers at the beginning of this example concluded that the wing should be improved because their statistics only considered returning aircraft and ignored those that were shot down and did not return. If such a statistical study , is neither comprehensive nor correct enough, or even wrong. Because the wing can still fly back after being shot, it means that the wing part is not a fatal place; and when studying those fighters that did not fly back, the key to the crash is that the tail or other places were seriously shot, and the results also prove that this is the case. Abraham Walder was right.

You see, the angle of observation and the angle of analysis are different, and the results are also different, even dangerous.

Famous Example 2 of Survivor Bias: The Uselessness of Reading

I read a joke that A graduated from elementary school, came into contact with society early and successfully became a big boss through hard work. One of his neighbors has a boy named B who worked hard to study and graduated from a prestigious university. B's mother told A's mother that her son graduated from college and applied for a job in a large company with an annual salary of one million. She was very happy. At this time, A heard it and knew that B was actually applying for A's own company. This is a once-popular joke, which says, "What's the use of studying? Aren't college graduates working for bosses with elementary school education?"

Similarly, many people around us are saying, so and so in the beginning. People who didn't study hard can still make a lot of money today, but many people who study hard will not fare as well after graduation as those who didn't study hard. And because there are many such examples, many people come to the conclusion that "going to school is useless" and "reading is useless".

These people who successfully become bosses after graduating from elementary school are actually just an exception. Because the base of people with low academic qualifications is too large, it seems that there are many. According to the official calculation of the Sixth National Census in 2010, the population with college education or above only accounts for about 8.7% of the total population. It can be seen that the number of people with low education is much higher than the number of people with high education. Therefore, even if the success rate of people with low education is much lower than that of people with high education, it will still lead to a large number of successful people with low education.

For highly educated people, ordinary people will pay attention to both successful people and those who are not successful. People with high education but are in trouble are particularly concerned and are easily regarded as news reports (such as previous reports) Which college student graduates and goes home to sell sweet potatoes, pork, etc.); as for those with low education, ordinary people tend to only focus on the successful and ignore the vast number of people with low education who are unsuccessful. It is precisely because these "silent data" are ignored when collecting statistics from the people that the erroneous conclusion that "reading is useless" comes to mind.

In general, the surviving bias of the theory that reading is useless is that people only pay attention to those who have not read or read little but still achieve success, while ignoring those who have neither read nor succeeded. The conclusion drawn in this way is inaccurate, unscientific and not comprehensive.

In statistics, we call the above two examples "survivor bias". Through the above examples of sources of survivor bias and cases of useless reading, it is not difficult to see that people are usually accustomed to only seeing successful people, and thus draw some unreliable "experiences" or conclusions.

I personally think that if you come up with a point of view, but the sampling range of this point of view is only limited to the circle of successful people, then this point of view is likely to be one-sided; if the sampling range is also Including losers, then the credibility of this view is relatively high.

Regarding learning, I have recently discovered that many parents have forwarded some experiences in successfully passing prestigious schools such as Qingbei in WeChat Moments, such as how to spend three years of high school efficiently, learning tips for Chinese, mathematics, English and other subjects. etc., and even like to repost some of the worldly truths. I feel that if you repost them, your children will be just as successful, and if you repost them, they will be just as smooth and social.

This is actually a mistake of survivorship bias, because they only see the experiences of successful people and fail to sum up the lessons of losers.

So, do you still want to keep reposting it?