This paper describes the data collection, data analysis, and findings that point to the importance of instructional context as a factor in understanding the concepts teachers use when they process information about pupils in their classrooms, and the predictions they make about pupil success in learning. Three aspects of context are examined: (1) level of immediacy (classroom, school, local community, and larger society); (2) rhythm of change (rapidly shifting factors, periodically shifting factors, and sustained factors); and (3) direction of impact (teacher attitude, teacher information processing, teacher behavior, teacher effectiveness, and teacher change). (JD)