Intraclassroom comparison of two arrangements for teaching profoundly mentally retarded children.

An intraclassroom (within-subject) comparison of two arrangements (one-to-one and small group) for teaching profoundly mentally retarded children was conducted. The dependent variables were teacher on-task time (the duration of minutes spent teaching behavioral objectives), the frequency of instructor turnaways per instructional minutes (the number of times the teacher left or turned away from the child being taught), the number of trials correct per child, and the number of objectives taught per child. A reversal design was used. Based on the first two variables, the one-to-one instructional arrangement appeared to be superior.