I should be clear...that classroom observations of teachers in a high school
setting seem effective. I know that when my administrator has visited my
room, he always has picked up on several improvements/changes/strengths.
Point being, they are accurate in seeing the strengths in the classroom. At
least in the high school setting, a lot can be seen in the tone of the room,
structure of the classroom environment, and how the instructor interacts and
teaches their pupils.
I grant that not all are as lucky as I and that I have a good situation but,
it can be done effectively. I would imagine that if someone watched your
classes, labs, and saw how questions were answered, etc. they could tell
where improvement was needed. They could also tell if a person was
incompetent. I think that people are afraid of having other people involved
because they fear judgment. If people shared more and invited people into
their classes before the dean, etc. had to get involved, if things were more
collaborative, struggling people could get help rather than they continue to
get poor student evaluations, nothing happens, and they are not effective.