Approximately 200 hours of observation of classes in 13 school districts, selected to represent diverse SES and expenditure levels, were coded for various dimensions of classroom activity structure. The coding categories were derived from prior work by Grump and Grannis. In addition, observations of individual students' on-task behavior were made. Results are presented which describe the salient features of mathematics and social studies classrooms at fifth-grade level. In addition, student involvement is examined in relation to various setting features in the context of a theoretical framework. (Author/MK)