Question about backtest result

[Erdenebayar Lamjav]

I bought EA robot, and I test it on strategy tester. It's result is very good, but when I test it on demo account, it loss. What is mean?

[Eleni Anna Branou]

How far back was your test in MT4 strategy tester? You should test it for at least a few months to 1-2 years to be sure.

Also the brokers slippage and swaps are not calculated correctly in the strategy tester, unless you much those values with your broker's.

Finally for how long do you test your EA in the demo account? Because its not right to back test an EA for some months and make conclusions after a day or two in a demo or a real account.

[Marco vd Heijden]

It means that the strategy tester does not predict demo or live market performance.