Some thoughts on most of existing algorithms here that shows good results in the backtests since 2002 exists in the system, in this period the interest rates were only going down, and any algorithm that works well on the last 7 years historically low interest rates, I predict that its impossible that rates will be so low looking into the future, its just about time till both inflataion and interest rates will go up and with that bonds ETF's prices will go significantly lower with stock market. The question is how can we hedge against this in the various algorithms (e.g. if we can measure interest rates increase trend with fundamentals and add inverse bond ETF or drop all bonds ETF from the portfolio)