The results of 11 studies of classroom practices used with the activity-based elementary science programs, ESS, SCIS, and SAPA, were combined quantitatively. All studies included control groups and employed techniques for coding lesson events. A composite category system was developed for combining study results. It was found that teachers using activity-based programs spent about 10% more time on student activity and 10% less time on talk than teachers using traditional methods. More direction giving, more higher level questions, and less lecturing were also reported. Teachers trained in program use spent less time giving directions, more time on activities, and less time on talk than untrained teachers using the programs. On the average, researchers coded slightly less student talk and slightly less student-initiated talk in activity-based classrooms.