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by cpascal 1962 days ago
This reminds me of a metaphor made by Burton G. Malkiel in “A Random Walk Down Wall Street”. He attempts to give a possible explanation to why there are star traders or funds that greatly outperform the market. It’s something I like to remind myself of from time-to-time.

The metaphor was a coin flipping tournament. You have a bracket of players who flip a coin against an opponent. In each matchup, the player that flips a heads advances to the next round to face another opponent who won a parallel matchup in the previous round. Suppose this is a 100 round tournament, that would mean the eventual winner would have had to flip a heads 100 times to win. You might look at this coin flipper and think they are an extraordinary coin flipper. That they have some innate ability to flip a coin and make sure it lands with the head sides up. In reality, it was just random chance that they flipped the coin correctly, they do not posses any more coin flipping talent than anyone else. They just got really lucky. You can potentially look at a successful hedge fund or trader through this same lens. They have survived the proverbial coin flipping tournament and random chance was on their side.

4 comments

This was a common investment scam in the past. Create an email newsletter, split it in half and give opposing advice to each side. You then keep ramping up the fees to the winners until eventually they become one of the losers. Once the list gets too small, create a new entity and start again.
I think you'll find it's not a real implementation. OP's example requires 2^100 people ~10^30

It's a similar problem with the email list.

50+ years ago Scrooge McDuck also had this happen to him. He had a treasure map for gold (In Antarctica I think) which he got conditional on profit sharing and he found gold.

The map sellers ran this scam, sold heaps of different maps because someone would find gold.

I personally don't think Scrooge McDuck was just lucky though.

I think this is the first instance of plot armor protecting exclusively against financial loss.
Either I did not understand it, or this doesn't make sense. If the head flipper moves ahead, then that person, truly flipped 100 heads.

Your example would have made sense, if you talking about the 100 times consecutive winner in a coin flip match, with each match, the winner can be heads or tails.

Good idea, but bad example: a 100 round tournament (single elimination) would require 2^100 humans, that is a 20 orders of magnitude increase!! You could do 32 rounds at most.
What if no one gets tails on a flip?

Is it the first person to first get heads or does it have to be consecutive