The Art of War by Sun Tzu

I Laying plans contd...

15. The general that hearkens to my counsel and acts upon it, will conquer: let such a one be retained in command! The general that hearkens not to my counsel nor acts upon it, will suffer defeat:-- let such a one be dismissed.

Notes by Zephyrist:

Promote and keep good generals, dismiss bad ones.

Of course in modern business this doesn't always work, bad managers get promoted because they have a good CV and strong interview skills. The difference would be what their old colleagues and subordinates think of them. If we could talk to those people regarding references and that culture became normal then bad managers would not get promoted.

You can apply Sun Tzu's consideration to recruiting a manager, a general / manager is nothing without his army. You must have knowledge of both to pick the strong general / manager.