Quote from silvermotion:
Hello and welcome
I will give you a very good advice about backtesting and tweaking your system based on the data you have available.
beware of 'death by tweakage'', This means that you will most likely be tempted to overparametrize your system so it performs the best possible way. Everyone do this at 1st and what will happen is as soon as the market conditions will change even by the slightiest bit, your system will fail horribly.
The secret in my opinion is to watch for convergence of data.
If you backtest and tweak a strategy on a index future (the sp500 mini futures are very popular), make damn sure that whatever indicator that improves your result on this one will also have a similar effect on another index future (the dow jones or nasdaq, etc)
unless your data converges, its not reliable, and you will lose money and be dissapointed, 2 of the worst enemies in trading.