如何判断交易中的风险与回报？我认为没人能给出准确的答案。环境在变化，风险与回报的问题也在变化。传统观点认为风险与回报的比例至少为2:1，风险止损至少是盈利目标的一半，所以如果你的盈利目标是100，那么止损应设置为50。
这个计划看起来很棒，在十次交易中只要盈利四次就可以了。但是我在现实生活中从未遇到严格遵守该原则的交易员。我从很多分析家、策略家、交易培训师等人口中得到过这类建议，他们异常相信这个原则，甚至愿意用早餐钱打赌。但我从没见过有人用2:1的方法来谋生。
为什么？
首要的原因是，没有做过交易过人不相信市场中会有这样的回报。市场中只有风险。市场和工厂不一样，不是你下了订单就会产生收益。事实上，市场会不断地妨碍你。假设你设置了100点的止损、200点的止盈。交易最初按照你期望的方向行进了199点，依照2:1策略，要达到200点的盈利目标才可以，所以你要继续等待。但是你猜接下来会发生什么？市场突然转向，你会惊恐地发现原本盈利的订单迅速转为亏损，然后突破你的止损点。你亏损了多少？表面上看你亏损了100点，但实际上亏损了299点。欢迎来到真实的交易世界，理论上的2:1风险回报比你想象的要复杂得多。
市场中的盈利其实是不可预测的。你唯一能控制的就是风险。所以我们会同时交易两个产品，会制定短期目标，会勤勉地调整止损以控制风险。虽然听起来很麻烦，但这是我们控制风险与回报的唯一方法。
Risk and Reward
How do you determine proper risk and reward in trading? I don't think anyone can ever provide a definitive answer to that question.The question of risk and reward always changes with the circumstances of the moment. The traditional view on risk and reward is to set the ration to at least 2:1 - risking half the amount of pips as you are trying to make, so that if your profit target was 100 then your stop would be 50.
In theory this sounds like a terrific plan. You only need to be correct 4 out of 10 times to make money. However, I've never met a real life trader who actually put this principle into practice. I've received plenty of such advice on this matter from analysts, strategists, trading coaches and a whole host of others who have never wagered so much as their breakfast money on a trade, but I have never seen the 2:1 ratio employed by anyone who actually makes their living from the market.
Why?
The primary reason is that most people who never trade, do not realize that there is no such thing as reward in the market. There is only risk. Markets are not like factories that manufacture profits to your order. In fact, markets do everything possible to frustrate your goals. Imagine a trade where you risk 100 points with a profit target of 200. Initially the trade goes your way and the floating p/l quickly rises until it reaches +199. Disciplined in your 2:1 strategy you wait for the profit target to hit so you can book another good trade. But guess what? The market suddenly stalls and then reverses. You watch in horror as the positive trade quickly turns negative and then drops through your stop. What was you loss? On paper you lost 100 points, but in actuality you lost -299 points ( 100 points on your stop and -199 you did not book). Welcome to real life trading where the “theoretical” 2:1 risk reward is far more elusive than you think.
The fact of the matter is that profits cannot be forecast in the market. The only thing you can control is risk. That's why we always trade with two units. That's why we always take short first targets and that's why we assiduously control risk by trailing our stops. It may not be glamorous, but its the only way we know how deal with risk and reward at BKT.
本文翻译由兄弟财经提供
文章来源：http://www.actionforex.com/articles-library/money-management-articles/risk-and-reward-2009011775435/