The image shows the analysis of bullet holes in all the Allies aircraft that returned from the battlefield. The bosses felt that all the areas on the airplane with the bullet marks should be made reinforced so that the bullets hitting will not damage the planes.
However, statistician Abraham Wald pointed out that the areas which *don't* have bullet holes should be reinforced. Because the planes which were hit in those spots *never returned*.
The original thinking of the bosses is called survivorship bias. They looked at only the survivors and formed opinions based on the survivors, without considering the ones who failed. And hence reached wrong conclusions.
Now consider Covid: if we ask all Covid patients how bad their Covid experience was, and most of them say it was not too bad. What does that mean? The point is that we are only asking the patients who survived. The patients who died aren't answering the questions. So you end up with incorrect conclusions just as in the case of the airplanes.
Naveen sir, please share some more info of your last tweet. How does pic relevant to WW2?
The image shows the analysis of bullet holes in all the Allies aircraft that returned from the battlefield. The bosses felt that all the areas on the airplane with the bullet marks should be made reinforced so that the bullets hitting will not damage the planes.
However, statistician Abraham Wald pointed out that the areas which *don't* have bullet holes should be reinforced. Because the planes which were hit in those spots *never returned*.
The original thinking of the bosses is called survivorship bias. They looked at only the survivors and formed opinions based on the survivors, without considering the ones who failed. And hence reached wrong conclusions.
Now consider Covid: if we ask all Covid patients how bad their Covid experience was, and most of them say it was not too bad. What does that mean? The point is that we are only asking the patients who survived. The patients who died aren't answering the questions. So you end up with incorrect conclusions just as in the case of the airplanes.