This paper discusses teacher evaluation, including why teachers should be evaluated, what should be evaluated, and how it should be evaluated. Major problems in the evaluation process are listed, followed by a more detailed discussion of the why, what, and how. The paper concludes that dissatisfaction exists in the field of education with current approaches to teacher evaluation. The reason is the failure of research to yield a shared operational definition of teacher effectiveness or adequate instrumentation for reliably measuring and assessing teacher performance. (Author/LD)