(from a scalpers perspective)
R:R is mostly important in swing trades and something below 50% prob. When you trade short term like scalping most of your R:R is a function of the market. Markets are moved by professionals that don't want to lose so it is more important to know where to hide your SL and not to overextend the TP.
Your expectancy is governed by:
entry - chance of your entry to be executed (limit order or even if you use market every market order can be looked as a placed stop order)
take profit - chance of the price moving to the tp
stop loss - chance of the price to hit sl before hitting tp
after you know these three elements (or at least their estimations) calculate your risk/reward and asses if the trade is worth taking. Not the other way around. As noted before you can't just decide how much reward you would like.
Better spend your time understanding what the market is doing like asking the questions:
1. are here mostly limit orders or stop orders?
2. is currently market overextending or in balance like in a tight range?
3. who is most likely to take the other side of my trade: scalpers or swing traders?
4. where do professionals expect to take profit or get out of a bad trade if it goes against them?
etc...
R:R is mostly important in swing trades and something below 50% prob. When you trade short term like scalping most of your R:R is a function of the market. Markets are moved by professionals that don't want to lose so it is more important to know where to hide your SL and not to overextend the TP.
Your expectancy is governed by:
entry - chance of your entry to be executed (limit order or even if you use market every market order can be looked as a placed stop order)
take profit - chance of the price moving to the tp
stop loss - chance of the price to hit sl before hitting tp
after you know these three elements (or at least their estimations) calculate your risk/reward and asses if the trade is worth taking. Not the other way around. As noted before you can't just decide how much reward you would like.
Better spend your time understanding what the market is doing like asking the questions:
1. are here mostly limit orders or stop orders?
2. is currently market overextending or in balance like in a tight range?
3. who is most likely to take the other side of my trade: scalpers or swing traders?
4. where do professionals expect to take profit or get out of a bad trade if it goes against them?
etc...