How does a good manager know that they are?
Imagine you were an archer. You fire your arrow and you get feedback immediately; either you hit the target or you don’t. You can adjust your technique and get instant feedback on those adjustments. In time you become better and better as an archer.
Suppose that you can’t see the target; it would be very difficult to hit and you would have no idea of the result. The only way you could tell how well you were doing was if someone, like a coach, told you.
Now suppose that they also can’t see the target – how can they give you feedback? All they could do is share with you some data about how often you fired the arrows or whether your technique looked OK or not. You might tell them how you felt; probably you would be frustrated.
Eventually the coach would stop talking about it because nothing helpful would be happening. In turn you would stop bothering and just fire off arrows in the right direction, probably as fast as possible, to get it over and done with.
Now let’s look at managing and coaching staff. How do you know if you hit the target? You probably try various things and look for feedback through outcomes and whether the member of staff looked happy or not. You might even have a discussion with your manager about how you think it is going.
But not directly paying attention to the member of staff and getting their feedback is as hopeless as firing arrows at a board and not knowing whether they hit or not. Ask your direct reports how well you are doing if you really want to improve as a manager.
Of course, if you don’t care whether you are a good manager, then that is a different problem altogether.