Markets coveredMatch OddsCorrect ScoreOver / UnderFirst HalfSecond Half
Statometrics
Calculator · from Lesson 7.4

Why do backtests lie?

What it’s telling you, step by step: Lesson 7.4: Overfitting and multiple testing

Try it · Random system generator
Your ‘winning’ system: +15.8%-20%-10%0%10%20%30%
Best system
+15.8%
Median system
-1.0%
Worst system
-13.9%
+10% or better
5 of 100
Not one of these systems has an edge, yet the best shows +15.8% over 200 bets. Over its next 200 bets it should expect about -1.0%, the same as the rest.
Winner each time you pressed (1)
+15.8%
Every system here is a fair coin: 200 bets at evens with no edge whatsoever. Each square is one system, placed by its ROI.
18+ only. Educational content, not financial or betting advice. Past results do not guarantee future returns. If gambling stops being fun, get free, confidential help at BeGambleAware.org.
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