如何判斷交易中的風險與回報？我認為沒人能給出準確的答案。環境在變化，風險與回報的問題也在變化。傳統觀點認為風險與回報的比例至少為2:1，風險止損至少是盈利目標的一半，所以如果你的盈利目標是100，那麼止損應設置為50。
這個計劃看起來很棒，在十次交易中只要盈利四次就可以了。但是我在現實生活中從未遇到嚴格遵守該原則的交易員。我從很多分析家、策略家、交易培訓師等人口中得到過這類建議，他們異常相信這個原則，甚至願意用早餐錢打賭。但我從沒見過有人用2:1的方法來謀生。
為什麼？
首要的原因是，沒有做過交易過人不相信市場中會有這樣的回報。市場中只有風險。市場和工廠不一樣，不是你下了訂單就會產生收益。事實上，市場會不斷地妨礙你。假設你設置了100點的止損、200點的止盈。交易最初按照你期望的方向行進了199點，依照2:1策略，要達到200點的盈利目標才可以，所以你要繼續等待。但是你猜接下來會發生什麼？市場突然轉向，你會驚恐地發現原本盈利的訂單迅速轉為虧損，然後突破你的止損點。你虧損了多少？表面上看你虧損了100點，但實際上虧損了299點。歡迎來到真實的交易世界，理論上的2:1風險回報比你想象的要複雜得多。
市場中的盈利其實是不可預測的。你唯一能控制的就是風險。所以我們會同時交易兩個產品，會制定短期目標，會勤勉地調整止損以控制風險。雖然聽起來很麻煩，但這是我們控制風險與回報的唯一方法。
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.
本文翻譯由兄弟財經提供
文章來源：http://www.actionforex.com/articles-library/money-management-articles/risk-and-reward-2009011775435/