BILLY CONNOLLY, the great Scottish comedian who recently retired from performing, had a joke about two men filming a lion for a wildlife documentary. The lion suddenly looks up. The men fear they have been spotted. One of them slowly removes his boots and puts on a pair of running shoes. “You will never outrun a lion in those,” says his colleague. “I don't need to outrun the lion,” replies the first man as he slowly ties his shoelaces. “I just need to outrun you.”

The joke rather neatly captures a particular approach to investing. What matters is not so much whether you can get ahead of some absolute goal for returns. The important thing is whether the asset you choose to invest in will comfortably beat the alternatives.