For example here are the back test results from one of my fairly simple MTF strategies traded on a 5 minute time frame. The quality of the trades looks pretty good with a 95% win rate and almost 24 gain/loss ratio and reasonable drawdown compared to profit – but the test period is just the most recent year and a half because of the 5 minute timeframe and it only opened 41 trades so that is not a lot of data or trades to be confident in. It will take years of forward testing just to get enough trades to be confident that it works! Had I been able to see it working this well in a 15 year back test period and seen it open hundreds of trades in that time then confidence to trade it would be much higher.