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I think that you may be missing the point of Fooled by Randomness. The point is knowing whether your success came from luck, skill, or both. It also shined a light on people who took high-probability, "sure bets" (selling out-of-the-money options) that paid off most of the time but would eventually bankrupt them if the stock price jumped.


Quite contrary, the point of the book is that it is very difficult to differentiate between skill and luck when random odds influence events.

For instance if you asked 1000 people to guess coin flips, on average one half will be wrong on each flip. So on the first flip you'd drop to 500, then 250, then 125, then 65, then 32, then 16, then 8, then 4, then 2, then you'd -- in a perfectly ideal scenario -- have one person left. A person that remarkably, "against all odds", guessed 10 coin flips in a row right! Surely they must be some sort of magician or seer, right? Yet their probability of guessing the next coin flip is no better than the people eliminated in the first round.

But that is exactly what we do with things like exceptional events: We find the person who was right about a set of events, among a collection of people guessing almost everything, and assume they've cracked the code. Even outside of financial situations (like being a guy who happened to have a portfolio that did great during an extreme black swan on October 19th, 1987, even if that same portfolio generally did terribly), just look at what happened with 9/11: Of all of the millions of scenarios that people concocted for fiction or just postulating, anyone who talked about a plane hitting the WTC suddenly became prophetic.

It's actually a pretty good book, as an aside.


The key question is how you determine the difference between skill and luck. Is that difference statistically significant and is their a different set of inputs that lead to this output?

For instance, Taleb's example of fund managers that beat the market for five years in a row. You start with a cohort of 10,000 and a 50% chance of beating the market each year. There will be a group of 300 or so fund managers that consistently beat the market 5 years in a row. This does not differentiate the lucky from the skillful. 1) Analyzing other cohorts that had higher success rates and 2) their investment strategies and decisions would be necessary to make the determination.

Well, a broken clock is right twice a day. Someone who always calls for a market correction will eventually be right. The real question is how will the investment strategy fair over decades or longer.

We may have different takeaways from the book. My takeaway was that one should invest in becoming skilled (learn strategies that work in the long run) rather than seeking or worshiping those who may just be lucky.




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