Reasons you win in backtests but lose in live trading

? Introduction

Most EA developers experience this.

Profits are shown in backtests.

But when deployed in real trading, it collapses.

Why is that?

? The market changes

The market is not fixed.

Trends.

Ranges.

Interest rates.

Volatility.

Participants.

Everything changes.

In other words,

what was optimal in the past

is not necessarily optimal in the future.

? The side effects of optimization

In backtests,

you can fit to historical data.

But overfitting occurs if you fit too much,

and you lose adaptability for the future.

This is overfitting.

? What matters is stability

High PF.

High win rate.

Low drawdown (DD).

But that alone is not enough.

What matters is that

profits remain even if you change a few conditions.

? MAEP perspective

Backtests are not the answer.

They are a hypothesis-testing tool.

They do not guarantee the future.

That premise is necessary.

✅ Summary

Winning in backtests.

That is only a starting line.