As an exercise it would be interesting to see if an idea that works well over 4 previous years then have the data available to see if the idea worked say 10 years ago.
I feel not many systems would survive the test.

I found that a min of 4 years data is the min to work off, if checking to see if an idea will possible fly in the future.

If one is into researching ideas, it is hard to go past the brilliant GTX
It will cost money to use it, approx $100 a week for updates & day to day data.
Past results for each year can be purchased going back approx 9 years.

I found many ideas that worked well over say 3 years then fell in a hole on year 4.
Thats the weird thing in the fascinating world of system research.

"Why is it so?" one may ask,to coin an old popular saying from the much loved, professior Sumner Miller .

Cheers.

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Cheers.