Evaluation is simply an attempt to determine the value of something or someone within the context of certain defined criteria. In the context of program evaluation, effectiveness is usually seen in terms of how well the teacher’s activity leads to desired outcomes. How students learn, however, is a very complex matter and effective teacher activity involves more than teacher-student exchanges in the normal classroom situation. It also involves knowledgeable planning, an understanding of the curriculum, how to create an effective learning environment for children, skills in working as a member of a professional team, and so on. This instrument identifies four components under which the basic criteria for teacher effectiveness in a teacher-librarian context can be evaluated.