You will often read something this ...
We use intensive market data back-testing of strategies or secret method or secret formula to prove or show that it can generate 10 to 15% ROC. This is our secret method or strategies which you cannot learn from any investment book outside.
Hmm ... like that arh!
You can! I can! LOL!
Not using any market data back-testing!
Here is all real data set over the last 17 years from Jan 2000 to Aug 2018
Uncle8888's proven secret method or strategies to generate at least 6% CAGR! LOL!
Hmm ...
When Uncle8888 generates 10 to 15% CAGR then can charge $5K training course ......