Since I started my first job in 1993, I've come across dozens of Job descriptions (JD) and titles, and interviewed countless people. But I've never seen a formal JD capture the one essential skill that is required of every manager, director, even CEO.
Its called Getting Things Done - and its a rather special skill that not many have.
You keep running into brilliant people who have a hard time turning ideas into actions. You keep running into analytical people who can turn in endless reports without many results, you see the self-proclaimed visionary who is sure he can provide a path for a company to follow. But rarely do you hear these words when you ask a candidate what his strengths are: "I get things done".
This is not to undervalue relevant job skills, intelligence, or analytical experience - all are necessary, but none is sufficient. Unless you can deal with reality, unless you can roll up your sleeves and get into the trenches, unless you are ready to take responsibility for Execution - you're not going to be truly effective.