This article will tell you when it is safe and unproblematic to use correlation in the
way that you imagine you can use it, and when you should take care. In particular it
will tell you about two fallacies that have claimed many victims. These traps are known
to statisticians, but not, we suggest, to the general correlation-using public. We will
help you avoid these pitfalls and introduce an alternative approach to understanding
and modelling dependency - copulas.