Interesting thing I heard today...James Altucher doesn't even trade systems...Not saying they don't work...just thought it was interesting as he wrote a book on them-- kk
I bought his book trade like a hedge fund, I only tried one system or so, but look at them all, the return is less than what youd get out of an index, no one he runs a funds of funds.
One can go to Wealth Lab (the old, still free, pre-Fidelity version) and test many of his systems. Most did well in the volatile years of 1999-2002, but many have broken down, and some trade much less frequently to the point that I have to question their statistical validity (not enough recent trades, iow).