This study investigated the consistency of classroom process variables. Four teachers representing the primary, intermediate, middle, and high school levels of instruction were observed for extended periods of time. Information about four classroom process variables was collected using the Five-Minute Observation component of the SRI Classroom Observation System. The process variables were: initiator of the classroom interactions, recipient of the interactions, intent of the interactions, and type and effect of the interactions. Spearman Rank Order correlations indicated high levels of consistency for the process variables for the four teachers over repeated classroom observations. Content analysis of the teachers' pattern of interactions showed that for three of the four teachers, classroom process variables remained consistent when the primary and intermediate level teachers taught different content to the same group of students and when the high school teacher taught the same content to different groups of students. Limitations of the study and findings are discussed in relation to previous and future research. (Contains 7 tables and 24 references.) (Author/SM)