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What is the Rahul Tewatia effect?
During World War II, statistician Abraham Wald tried to determine where one should add extra armour to airplanes. Armour could not be applied everywhere on the plane as that would make the plane too heavy to fly. Certain sections had to be selected for reinforcement. The military thought of applying armour to the most-hit areas of the planes that returned as that showed the areas that needed further strengthening. However Abraham Wald pointed out that the military did not account for the planes that did not return. The areas where returning aircrafts took damage were the areas where a plane could take damage and still return home. This meant that planes that did not return were most likely hit in the places where the returning planes took no damage. Those would be the areas where the excess armour should be deployed.
Survivorship bias is a common logical error which occurs because we assume that success tells us the whole story. We fail to account for failures, often due to their lack of visibility. Abraham Wald considered not only the flights that returned but also the flights that did not return. This allowed him to make an astute decision.
A more popular and intuitive example is when we look at billionaires for inspiration. “I am going to quit college because Bill Gates did so ”.This is problematic as all the people who quit college but are now not doing so well are not accounted for in that statement. So now that I have already described survivorship bias to you, lets get to Rahul Tewatia.
Rahul Tewatia is an Indian cricketer who in 2020 was playing for Rajasthan Royals in the Indian Premier League. In a game against Kings XI Punjab, Rajasthan Royals was chasing 224. Rahul was struggling initially. He could barely get bat to ball. The commentators and fans watching this may have been hoping for him to make a move on or simply sacrifice his wicket for the good of the team. He had scored 8 runs off the first 19 balls. Then out of nowhere he went on to smash 45 runs off the next 12 balls. In that process he smashed 5 sixes off Sheldon Cottrell. He eventually ended up making 53 off 31 balls and Rajasthan Royals ended up chasing the mammoth total of 224.
Twitter went crazy after this match and Tewatia was hailed as a hero. While his performance was spectacular to say the least, many articles popped up talking about how one should never give up, even if that means playing very slow with the hope of catching up later. I don't think I agree with this approach, especially if you do not have a track record to back it.
It is problematic as more often than not, batsmen struggling to get bat to ball end up wasting a few balls and eventually getting out. These common occurrences don't make the headlines as they are not newsworthy. They are like the planes which did not return and hence were not factored into the analysis.
Furthermore if a batsmen wastes balls and gets out it puts pressure on other batsmen who may get out in the process. Then looking at the scorecard as a whole shows that the entire team failed while in reality the middle order may be coming under extra pressure due to the top order.
Looking simply at his innings and coming to conclusions is an example of survivorship bias. I by no means am trying to diminish the glorious innings Rahul played. It truly was amazing. However I would think twice personally before promoting that type of cricket as the way ahead. (especially if you are chasing a mammoth total )
Survivorship bias is also common in the financial markets when one views the performance of stocks or funds as the performance of the market, without factoring in all the funds that went bust.