This study describes the processes involved in developing an observational system for analyzing teacher classroom behavior. Three-hundred-sixty sixth grade students reported their perceptions of their teachers by responding to a questionnaire and to the same questions during interviews. The students' perceptual reports were analyzed to determine usability, with 7,700 items found acceptable. Adjective descriptors were clustered into a twelve-category observational system. Perceptual statements were randomly selected and supplied to a panel of judges for sorting into the twelve categories, yielding a mean inter-judge percent agreement of 83. The system was taught to observers who used the system to code ten videotaped teaching episodes. Inter-rater reliability coefficients were calculated yielding an r = .61. (Author/CTM)