Abstract
An A-B-A-B time-series design was used to determine the effectiveness of a group contingency strategy in modifying on-task behavior of behaviorally disordered students in a physical education setting. A younger group (n = 12) with a mean age of 7.8 years, and an older group (n = 11) with a mean age of 11.2 years, participated in a study in which activity reinforcement for each group was contingent upon correct observation of the rules established for class. The group contingency strategy was significantly effective in increasing the percentage of on-task behavior of both groups of students. In addition, there was no significant difference in the response to treatment between younger and older students, and there were no individuals within either group who did not respond favorably to treatment.