I am in the middle of Fooled by Randomness by Nassim Nicholas Taleb. He talks about how we tend to draw the wrong conclusions about mutual fund performance by looking at the historical performance of today’s mutual funds. We don’t include the performance of all the funds that were closed or merged, generally on account of poor performance, because they aren’t around. This is called Survivorship Bias.
I find that Survivorship Bias is very useful in explaining the Godman phenomenon as well.
Let’s say you are diagnosed with an untreatable disease that has a survival rate of 10%. You make a trip to a godman. He blesses you. Two weeks later you die. The godman carries on blessing other people. But you are dead and unable to come back and ask him for an explanation for why his blessing didn’t work.
Let’s say that you are one of the lucky 10% who survive. You are so grateful to the godman that you become a devout follower. Not just that – you become an evangelist. You speak of his greatness to anyone who would care to listen. You wear conspicuous marks of your devotion on yourself – a ring, a mala – and put up his images on the walls of your house.
Let’s reduce this down to numbers. From the godman’s perspective, the ‘return’ on his blessing is zero 90% of the times when the person blessed, dies. But 10% of the times the person blessed survives and becomes a devotee and an evangelist. As long he blesses a lot of people, the odds are in his favour. The number of his followers will grow.
This was a very simplified version of reality for which the survivorship bias explains things quite well. But reality can be more complex. For instance, the blessing may be sought by a family member and not the dying person. Or the blessing may be sought for a less morbid reason – say success in a new venture.
Even in these cases you can explain how essentially random post-blessing results can still have positive outcomes for the godman’s following. Human nature makes this possible. People who are disappointed with how things turn out post-blessing may not become devotees but will probably not start advertising the fact that the godman is a fraud. But people who get what they had wished for become evangelists. The outcome for the godman’s following is thus biased towards a positive outcome. Over thousands and thousands of blessings, random events will cause a net increase in the godman’s following. Let’s call this the Evangelism Bias.
The Evangelism Bias explains other (seemingly) less irrational behaviour as well. Homeopathy, for instance. There are no clinical trials that can demonstrate its efficacy. However, it is widely used, especially for chronic diseases. The Evangelism Bias can explain the success of homeopathy but only if there is no other negative effect. Thus it is important that homeopathy produces no side effects and that it is easy to administer (sweet balls of glucose – can’t get any easier). Ayurveda, doesn’t always have this advantage. ‘Go Mootra’ as a treatment for anything is unlikely to get too popular. Chyawanprash, on the other hand, is popular.
Before you go and put me down as a rationalist preaching from Mt. Reason, I must admit that my family and I have often resorted to Ayurveda and Homeopathy when modern medicine hasn’t given us the answers. No godmen yet, but there’s still time for that. Taleb, in his book, contends that human beings aren’t wired to think in terms of probability and random events and carry many biases within themselves. That may be so, but when you are facing a chronic or life-threatening illness, and the doctors have nothing more to offer, you can’t just sit there. You feel the need to do something. And to have faith in something, anything.
Some of these ideas were developed in conversation with Gaurav Rastogi.