Anyone who has developed a worthwhile, robust trading system would in my opinion try to manage both HIS OWN and other people's money with it. He'd put some effort into starting and marketing his own fund rather than just try to flog the code.
What would I need to know to decide whether the system was robust? Well..
1) BACKTEST the system on AT LEAST 25 years' worth of historical data across ALL liquid markets. I'm not interested if the system worked brilliantly on Brent Crude for the last 6 months. The backtesting should assume a realistic transaction cost for each trade. I'd expect to see the backtesting done on software that can test open position management algorithms on a portfolio level - and they're not too many packages like that.
2) Based on these results:
i) What is the worst drawdown? How long, how deep, and could you live with such an experience?
ii) What's the annual variance of returns like? High variance means a very volatile (i.e. painful to live with) system.
iii) Finally - does the average annual return look decent?
And after all that I'd never BUY the algorithm. I'd let the developer manage some cash and pay him 2+20.
What would I need to know to decide whether the system was robust? Well..
1) BACKTEST the system on AT LEAST 25 years' worth of historical data across ALL liquid markets. I'm not interested if the system worked brilliantly on Brent Crude for the last 6 months. The backtesting should assume a realistic transaction cost for each trade. I'd expect to see the backtesting done on software that can test open position management algorithms on a portfolio level - and they're not too many packages like that.
2) Based on these results:
i) What is the worst drawdown? How long, how deep, and could you live with such an experience?
ii) What's the annual variance of returns like? High variance means a very volatile (i.e. painful to live with) system.
iii) Finally - does the average annual return look decent?
And after all that I'd never BUY the algorithm. I'd let the developer manage some cash and pay him 2+20.