Concept: Opportunity cost, comparative advantage What’s wrong with this picture? It’s nice of Superman to rescue a kitten, but has he considered the opportunity cost of doing so? Rescuing kittens is so easy that children often do it. With all the accidents, crimes, and natural disasters that occur in the world, surely he could spend his time more productively. The concept of comparative advantage suggests that Superman should focus on tasks that others can’t do well, like stopping runaway trains or transporting nuclear weapons into deep space so they can detonate safely.