Principals of elementary and secondary schools in Idaho (N=246) responded to a questionnaire that asked them to identify some causes of teacher failure. The major problems leading to teachers being placed on probation or not having contracts renewed appeared to be in the areas of: (1) behavior management and student motivation; (2) personality and attitude; and (3) planning and communication. Prevalant among the principals' comments were observations on how the teacher worked with students, parents, and the school administration. In a discussion of the results, it is suggested that in teacher training there should be greater emphasis on interpersonal communication, planning, and classroom management skills. (JD)