Meaningful and useful evaluations of teaching and teachers must not only identify and define all the mitigating contexts, but must also account for their influences, both constructive and negative. Among the contextual factors that need to be considered in planning teacher evaluations are: student characteristics; goals, objectives and curriculum mandates; inservice opportunities and human support services; materials, media, and facilities; and organizational structures and processes. The influences of leadership, decision-making power, and the climate of professional worth must also be defined. The major purpose of teacher evaluation is assumed to be improvement of instruction to provide students with the broadest possible range of knowledge, skills, attitudes and behaviors. The context for this purpose includes characteristics of the community and their effect on a teacher's ability to demonstrate proficiency. (Author/CM)