Be Careful With Unknown Data [cartoon]
When dealing with data, professionals should be extremely cautious with unknown unknowns. As former United States Secretary of Defense Donald Rumsfeld said: "There are known knowns; there are things we know that we know. There are known unknowns; that is to say, there are things that we now know we don't know. But there are also unknown unknowns – there are things we do not know we don't know."