Quote from mizhael:
So after adding the stop-loss logic and even after optimization, the Sharpe ratio is only 4% higher. Shall I conclude that it is not worthwhile adding this stop-loss mechanism and parameter?
Having a stop-loss is a prudent way to improve a strategy. In practice, you want to limit the loss in case the unexpected happened.
On the other hand 4% improvement is in the range of statistical error unless the number of trades in the backtest is in high thousands.