WebSeitz/wikilog
z2008-09-16- Taleb Limits Of Statistics
is a Product Manager/CTO with a track-record of bringing a business perspective to building agile product-development teams for start-ups, and is seeking a senior role in an entrepreneurial organization building disruptive Internet-driven products.

(backlinks off) (map off)
(search off)
last edited by BillSeitz on Jan 6, 2009 6:06 am

on on the limits of [Statist Ics]. Examples: , . Close to 99% of the variations, over the span of 20 years, will be represented in 1 single day. As I show in the appendix, this is typical with [ANY] socio-economic () variable (commodity prices, currencies, inflation numbers, , company performance, etc. ). No known econometric statistical method can capture the probability of the () event with any remotely acceptable accuracy... This absence of "typical" event in Extremistan is what makes -s ludicrous, as they make events look binary. "A war" is meaningless: you need to estimate its damage - and no damage is typical... The "" might work in the first three quadrants; but it certainly fails (and has failed) in the fourth.

Phronetic Rules: What Is Wise To Do (Or Not Do) In The Fourth Quadrant ()

  1. Avoid Optimization, Learn to Love Redundancy (). The only weak point I know of financial markets is their ability to drive people & companies to "efficiency" (to please a stock analyst’s earnings target) against risks of extreme events.

  2. Avoid prediction of remote payoffs

  3. Beware the "atypicality" of remote events.

  4. Time. It takes much, much longer for a times series in the Fourth Quadrant to reveal its property.

  5. Beware .

  6. Metrics. Conventional metrics based on type 1 randomness don't work.

  7. Where is the skewness?

  8. Do not confuse absence of volatility with absence of risks.

  9. Beware presentations of risk numbers.

So how do you make decisions and weigh trade-offs?

See : |


 




Bill Seitz, fluxent at gmail dot com, Weblog