Two methodologies for teacher-focused process evaluation--rating scales and systematic observation--are discussed and comments are made about their characteristics and effective utilization to improve teachers' performance. Process evaluation, referring specifically to the act of evaluating what teachers do in their classrooms, may be of formative or summative nature. Formative evaluation can be used to monitor what is happening and serves as the basis for making decisions about modifying teacher behavior. Summative evaluation is a quantitative statement that summarizes how well the teacher has been performing. Rating scales require the observer of events to structure, weigh, and relate many perceptions before reaching a conclusion. Rating systems would seem to be better suited to summative forms of evaluation. The second method, systematic observation, deliberately focuses on a sharply delimited set of process factors or dimensions. Both teacher and supervisor have information on a single aspect of classroom process that yields ideal formative data. The two approaches can exist if the organization ensures that the rating and observation methodologies employed are recognized as having separate and independent purposes and steps are taken to protect the integrity of each. (MLF)