The Social Science Observation Record (SSOR) is a systematic observation system designed to abstract and describe class discussion, specifically those discussions directed toward value clarification as an aspect of subject-matter instruction. The objective and yet diverse nature o category observation systems is described and an explanation is synthesized of how pre-service and in-service teachers may use category observational systems to study their behavior as teachers. A model of class discussion relevant to student understanding and to value clarification is presented and specific categories are identified and described of student and teacher behaviors through which student understanding and value clarification behaviors can be planned for and employed during class discussion. The knowledge and skills necessary for teachers to organize and interpret the data are discussed. Empirical studies are reported with regard to the modification of teacher and student behaviors, and methods by which observers have been trained to collect data with reliability using the SSOR are described. (Author/RC)