Control Charts and System Forecasting, 01/20/08
Control charts
can be used to monitor and predict the future performance
of trading systems.
In the example below, we can watch an actual trading system begin to fail. Chi^2 is spiking
showing that results are becoming less stable,
the ratio of wins to expected wins is trailing off and the profitability is trending down.
All early warnings of a system in trouble.
There are two options when faced with a trading system that is failing: fix it or throw it away.
Since the system above is an old friend, I opted for fix:
One interesting note is the cyclicality of the new system - something
that does not show up in its other charts and statistics - I'll have to work on this.
Ralph Vince has a method for working with cycles in
The Handbook of Portfolio Mathematics; sadly, I can't find the page right now.
[01/21/08 hac - pages 27-41. I'm reminded just how indispensable this book is.]
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Henry Carstens
Vertical Solutions
carstens@verticalsolutions.com
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