In Evaluating America’s Teachers, W. James Popham writes:

Formative teacher evaluation describes evaluation activities directed toward the improvement of the teacher’s ongoing instruction … summative teacher evaluation refers to the appraisal of a teacher …

… a teacher who needs to improve must honestly identify those personal deficit areas that need improvement. Weaknesses can’t be remedied until they’ve been identified, and who knows better what teachers’ shortcomings are than those teachers themselves? But if the teacher is interacting with an evaluator whose mission, even partially, may be to excise that teacher from the teacher’s job, do you really think most teachers are going to candidly identify their own perceived shortcomings for such an evaluator? Not a chance!

Suggesting a major overhaul to the way we are doing things.