@indigomoth - It might in fact be entirely up to the management what kind of goals you are reaching for as a supervisor. As it says in the article, they might decide to set some goals for you after an analysis of your performance.
I think this would be difficult to hear, but then no one is perfect. I know I'm not. If I had someone give me a particular goal for the coming year in order to improve my performance as a supervisor I would try to take it as a learning experience and opportunity rather than an insult to the work I've already done.