Shaun,

The 5% is quite high because that particular system has a very high strike rate and I am willing to put up with some volatility in the bank. Obviously you need to work out the appropriate percentage for each “system” depending on the strike rate (higher strike rates can have much higher percentages) and how much variance you are willing to have in your betting bank. So a low percentage will give you quite a slow but steady growth (assuming you have a profitable system!) whilst a high percentage will accelerate the growth but you will have more “ups and downs” as you go. In a way it is all linked back to the Max Drawdown figure that Chris mentioned initially and working out how many “steps” backwards you are willing to take in this situation – you can then work out what % will give you that result (in my case the 5% works out at about 2-3 backwards steps in the worst case drawdown scenario I have estimated).

The scary thing is if I used Kelly I would be betting around 20% of my bank on every bet (maybe that would give me a better profit in the end but the other week I would have lost 50% of my accumulated bank when I had 3 losers in a row – a bit too aggressive for me!).

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"Computers can do that????" - Homer Simpson