Its funny how some folk use the word "Back fitting " as a derogatory word.

If someone put forward a system with a proven failure rate over the last 150 bets , would anyone want to put real money on it.?

I very much doubt it.

Back data is all we can go on to start with, because the future is not available.

One could argue that using rules like "must have run in last 7 days" as back fitting so as to show a profit.

Example
Neural std setting - Top selection
Must have run within 7 days.

These rules show an excellent profit according to the UB system checker.
If you can get it to work now.

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Cheers.