I'm surprised to see people keep arguing the simple Risk:Reward concept and the viability of it. I believe it should not be a really complied idea to deal with.
The goal of trade is to create profit. It's not required to have a minimal RRR, but the combination of RRR and winrate needs to become profitable, and of course the more profitable, the better.
Note that RRR is Risk:Reward, the bigger is the worth, the risker is a trade.
In a simplified model, breakeven trades are discounted and each trade risk the exact same amount and target to the same amount of reward.
Thus,
Average Profit/Loss per trade = WinRate * Reward - (100% - WinRate) * Risk
For a profitable method:
WinRate * Reward - (100% - WinRate) * Risk gt; 0
WinRate - (100% - WinRate) * RRR gt; 0
Therefore,
.... RRR
WinRate gt; ----------
... (1 RRR)
by way of instance, for in a trading system, a trader risk 5 unit for 1 unit payoff.
The WinRate must be achieved to become profitable is 5/(1 5) = 83.3%
If such a WinRate is attained, it is a profitable method.
But to answer just how profitable a method is, we need to create use of the idea of profit element.
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