Backtest red flags: why a great backtest fails live
A backtest is a story about the past. Some stories are honest. These are the tricks that make weak strategies look strong.
Costs left out
Spreads, commission and slippage are small per trade and huge over hundreds of trades. A backtest run on a zero or fixed tiny spread can show profit that real costs erase completely. Always ask what spread the test used.
Too short, too lucky
A few weeks or a few dozen trades can look brilliant by pure luck. You need enough trades, over enough time, to tell skill from noise.
Fitted to the past
If a strategy was tuned with many settings on one period, it learned that period's noise. It will look perfect there and disappoint everywhere else.
Martingale and grids
Adding size after losses, or stacking many positions on one symbol, produces long smooth curves and rare, account-ending losses. A test that ends before the bad day looks amazing.
Figures that don't add up
Check the report's stated profit factor and net result against its own trade list. If they disagree, the report has been edited.
The latest stretch matters
If the most recent months are much weaker than the start, the edge may already be gone.
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NoCap Edge checks MT4 and MT5 backtests and statements for all of these and grades them A to D on the Cap Meter, with the proof behind every number. Free to start, no sign-up, not financial advice.