Wednesday, August 15, 2012

The concept of R

R is an important letter in my trading world. It quantifies both the risk I place on each trade, as well as giving the reward achieved in relation to the equity risked when opening a position.

As everyone has their own ideas on risk management parameters, it can be argued that the overall R achieved can be calculated by all traders in a uniform manner.

All things being equal, the reward to risk ratio should be as high as possible - this, combined with the win percentage, determines the overall expectancy of your system.

As trend followers, we are used to having a historical win percentage below 50%. However, as we strictly control our losses, and let our profits run, we end up with an overall positive expectancy.

Take an example whereby the win rate is only 40%, yet when averaged out our wins are three times bigger than the size of our losses. This creates an overall expectancy as follows:

(40% x 3) - (60% x 1) = 1.2 - .6 = +0.6R

In this example, we achieve an overall expectancy of +0.6R, which means we gain an average of 0.6 times what we risk across the total population of all trades (winners and losers).

So, if you were risking say £100 per trade, in theory you earn an average of £60 for each trade taken, regardless of whether its a winner or not. Two things to bear in mind here:
  • The above example does not account for slippage, execution errors, etc.;
  • This assumes you risk the same monetary amount on each trade ad infinitum
When calculating your overall expectancy and your average R per trade, you also need to ensure that this is calculated over a meaningful sample of trades, as well as taking into account both favourable and non-favourable market conditions.

The average R will remain the same whether you trading a £10,000 account or a £1million account. If, however, you use fixed fractional money management, and increase or decrease your position size (in monetary terms) based on your actual performance, then the beauty of compounding your equity will mean that, providing you are using a system with an edge, your position size will increase over time. If you are able to maintain your average R going forward, then your account balance will start to increase sharply.

2 comments:

  1. This is a thought i'm struggling to get out of my mind at the moment. Last month I made £170 on the 'paper' value of my portfolio (not banked profit). This was with a £1000 capital of which about 25% was tied up in open positions. Unfortunately i'm still about £180 down overall since I started in April 2012.

    Yet, if I could make say £200 profit for a 12 month period it does make me wonder. If I had a £10,000 account, that £200 profit would be £2000 profit. If I therefore had a £50,000 account that would be a £10,000 profit for the year.

    Of course, it's all speculation whether i'll make a profit this year. But it doesnt stop me racking my brains how I might be able to raise the cash outside of spreadbetting to raise my capital and therefore my potential profit.

    I've also found a lot of trending trades that I've not been able to get into because it's too rich for me. e.g. the S&P500 seems to trend nicely. Yet IG Index want £5 a point minimum bet. With a larger capital i'd be able to play it, but at present the stop required to stay in the trade for long enough is too wide for me to afford it. More capital opens more doors and could lead to better profits perhaps.

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  2. Trading is a marathon not a sprint. Sticking to your rules (especially risk per trade) together with the power of compounding your returns will get you there over time. Trading much smaller sizes in the beginning will help you solidify your approach and gain confidence in your system. If at THAT point, you have additional capital to trade, then great. But I'd wait until you have full confidence in your method.

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