Wednesday, September 28, 2005

Reversion to the Mean

Interesting post from Michael Covel titled Reversion to the Mean. Thanks to Ugly Chart for the FatKat link which triggered a search for James Simmons (Renaissance Technologies) which then guided me to Michael Covel's post. Funny where someone's post will take you. :)

Back to Covel's post. This talk of the next landing likely to be average in regard to pilots garners the question...will your next trade likely be average? Is there some dependency out there to explore in your trading system's position sizing methods? By following the Martingale method, am I rewarding my perfect landings (increasing size of next position) and ridiculing my bad landings (decreasing size of next position)? Oh, ideas to test...

Side Note
We were without power today and this hundred degree weather was a killer. I'm writing to you with a big smile on my face because just after FEMA came around my neighborhood bullhorning that they have no idea when power would be restored...the power was restored! Yeah! Having electricity never felt so good. Even if it's only for a short-time until the next rolling black-out.

Wanted to share a memory I have of my mom that might prove insightful. My mom lived through a lot...but I think the top two things that really put the fear in her were the hurricanes and gas crunch of the late 70's/early 80's. Know what I remember? She never allowed her car's gas tank to get below half a tank. Never. She would keep that sucker topped off every opportunity she got. Kinda like my grandpa after farming through the Great Depression...never kept money in the bank. I wonder, has a whole generation of people passed through these 25 years not understanding what a precious and valuable thing commodities can end up being? Only to experience it first hand over these past few months?

Know what my wife's worry is now? Someone stealing gas out of her car. Not stealing her car...but her gas! Remember when it used to be a big thing to have a lock on your gas cap? To be honest, I grew up never understanding why you'd need a lock on your gas cap. Now, I do. Another story for you...

While waiting in Houston evacuation traffic...everyone was running on gas fumes. The longer it took, the more gas it ate up. One woman was in her car staring off into space, frustrated with the hours she had spent in this traffic, only to witness someone beside her car syphoning off her gas. While she was driving it mind you. She immediately got out, yelled at the guy, and he ran away...cut short of his objective...but with a little more gas than he had before.

Have these past 20 something years been a perfect landing in commodities?

Are we headed for a Reversion to the Mean? Something I speculated back in March in my Canary in a Coal Mine post?

Finally, please keep all the people who still do not have electricity due to Hurricane Rita in your thoughts and prayers. We are having heat records blown out of the sky this week (100+ degree days), no breeze, nothing. And thoughts and prayers for all the men and women of the utility companies who are working around the clock to get power restored.

Later Trades,


Update: Wanted to clarify a bit on the term Martingale. When I referred to Martingale in the above post, I was referring to a specific type of Martingale commonly known as Anti-Martingale. Where you increase bet-size based on winning and decrease bet-size based on losing. The conventional Martingale often referenced in the BlackJack world back in the day increases bet-size on losing.

A few links to explore on Martingale...
Position Sizing by Michael R. Bryant
The Truth About Betting Systems
Betting Systems and the House Edge
Exposing the Gambler's Fallacy

A few links to explore on the Law of Averages and Gambler's Fallacy...
Law of Large Numbers and Gambler's Fallacy
The Law of Large Numbers

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