Friday, October 16, 2009

The Black Swan -- Nassim Nicholas Taleb

I read this book a few months ago, but it resonated with me. In particular the book critiques using the bell curve and other standard statistical techniques as if they are infallible. Many issues in our world deal in exponential or extraordinary events. Our most recent economic crisis was a series of unlikely things all conspiring to create a recession. All of this leads one to consider black swans.

A black swan is a seemingly impossible thing that occurs and causes great ruin to those who bet against it. A simple example of this is if a bank is making loans to farmers and only farmers. While it is unlikely that the bank won't make money, if all the topsoil were to simply blow away the bank would almost certainly fail. A good black swan is making it as a muscian, making it as a reality TV star, and getting on the NY Times bestseller list.

So, things to take away (in the style of the book)

Is this a measure that lives in mediocrastan?
Does this thing benefit from Black Swans?
Can one maintain a bleed strategy? (Many small losses, few HUGE wins)
Absence of proof =/=> proof of absence
Scaleability => fractals and similarity (NOT normality)
hyper-conservative "risk-taking" (reduce exposure to negative black swans)
hyper-aggressive in areas "needing caution" (Maximizing exposure to positive black swans)
skeptical about confirmations
no-nonsense/practical about academic matters
intellectual about practical matters

"Don't run for trains" It is more difficult to lose at games you set up.

Using a measure (profits) as a cause for survival is circular. (Post-ante selection bias is bad!)

Imagine the million failed people. 'I'd rather be lucky than good'

A Random Walk Down Wall Street - Malkiel

I'm working on reading through this book. It's a book about the financial markets written with the intended audience of investors. It has been recommenced to me off-handedly by my Money and Banking professor from spring '09. I'm a third to a fourth of the way through.

It's funny to hear descriptions of quants being able to value a firm with, 'a few presses of a calculator'. Now-a-days valuation of firms seems to be done in time measurements where electron cycles are a relevant time division.

The best part of reading this book is the history it provides. The author is attempting to explain contemporary methods for picking stocks. But because this 4th edition book was published in 1985 it's now an explanation of history. Understanding the Firm Foundations theory and Castles in the Sky theory helps to contextualize the criticism of economists and other thinkers of speculation in the stock market today. The "Black Swan" gains additional meaning now that I understand the object of critique as well as the critique.

(MORE TO COME...)