People need information to be able to improve. Everyone in a school benefits from good evaluation. Everyone is entitled to good evaluation. Evaluation must highlight and explicate strengths. Evaluation must indicate areas for improvement.
Evaluation is based on data.
There is no ONE approach that will work for all schools. There are good and bad evaluation systems. A bad system is worse than no system. Those to be evaluated are involved in creating the process. Adults going through a process of evaluation are powerful role models for students.