It becomes inappropriate, meaningless, and useless to make specific inferences from invalid measurements. Evidence of validity must be accumulated to support inferences made from evaluation results. Reliability means consistency - an evaluation always must give similar scores, ranking, or ratings for similiar tests, regardless of the evaluator or the evaluated. Effectiveness implies that the evaluation provides results in their most useful format. Summative evaluation yields a teacher performance score or rank that does not have to be interpreted to be used for accountability.
Formative evaluation initiates the improvement of weak areas.
Efficiency refers to spending time and money for evaluation training, materials, and procedure to ensure the desired results. Present evaluation programs consist of varying combinations of the following components. An updated, formalized version, the Teacher Perceiver Interview, reduces possibe interviewer bias. Used for initial certification and hiring decisions, the disadvantage lies in its degree of validity. Most studies of NTE results and evaluations of teacher performance show low correlation.