Strategy Tester differences between Demo and Live accounts using every tick based on real ticks

[william_chapman]

Hello everyone,

I think I already know the answer but I'll ask anyway. When testing an EA on both a demo account and then a live server I get a much much bigger % gain on the real account. I'm trying to figure out why.

I have tested 2 different EA's with 2 different brokers and the phenomena is the same. Both EA's perform better on the live account (in the strategy tester) than on the Demo account for BOTH brokers.

I believe it's because of potential overfitting due to inaccurate historical tick data. For my testing. it was only from 2022 - date, and the history quality for both demo accounts was 100%, but for the live server

accounts it was less than 50% on both brokers. I'm not a mathematician but I believe this is why and there is no reason to expect such a massive return and it makes more sense to trust the demo servers tick quality

for expected return ect.. 

Please let me know what you think.

William