Targeted Professional Development for Teachers

There have been studies that show there is very little correlation between educational degrees and teacher effectiveness in the classroom. To me, part of the problem is teachers pursuing generic training or graduate degrees. Nevertheless, I believe there is a way that performance evaluation, with the help of self, peer and supervisor evaluation can achieve targeted professional development that could improve key skills in the teacher.
For example, if a peer observes your class and sees many students off-task because of behavior, he/she can suggest class-management books, courses, articles or webinars. In terms of a self evaluation, a teacher might realize that his/her technology skills are not on par to what the students requiere. At this point, the teacher might recognize the importance of those skills and decide to take some graduate courses on educational technology.
There is some controversy if administrators should be both coaches and policemen. When a supervisor coaches a teacher, he/she needs to be careful and analyze if the teacher should be "coached up" or "coached out". When a teacher is clearly unhappy, unmotivated and struggling beyond what professional development can help with, then the administrator should coach them out. In most cases though, administrators should positively give advice on what resources or classes a teacher should take a look at. There is a thin line between what a teacher could consider genuine positive advice, and threatening criticism.